Integrated process for the manufacture of methylchlorohydridomonosilanes

Abstract

The present invention relates to an integrated process for the manufacture of methylchlorohydridomonosilanes in particular, from products of the Müller-Rochow Direct Process.

Claims

1. A process for the manufacture of methylchlorohydridomonosilanes, selected from the group consisting of Me.sub.2Si(H)Cl, MeSi(H)Cl.sub.2, and MeSi(H).sub.2Cl, comprising: subjecting a silane substrate comprising at least one silane selected from the group consisting of: (i) monosilanes, (ii) disilanes, (iii) oligosilanes, and (iv) carbodisilanes, with the proviso that the at least one silane (i) to (iv) has at least one chloro substituent, a) to a hydrogenation reaction with LiH, and b) to a redistribution reaction, and c) optionally to a cleavage reaction of the Si—Si bonds of the di- or oligosilanes or the Si—C-bond of the carbodisilanes, and d) to a separating step of the methylchlorohydridosilanes, wherein the process is carried out in the presence of an ether solvent having a boiling point of greater than 70° C., in the absence of AlCl.sub.3, and wherein (i) the monosilanes are selected from the group consisting of the general formula (I),
Me.sub.xSiH.sub.yCl.sub.z  (I), wherein x=1 to 3, y=0 to 3, z=0 to 3, and x+y+z=4, (ii) the disilanes are selected from the group consisting of the general empirical formula (II),
Me.sub.mSi.sub.2H.sub.nCl.sub.o  (II) wherein m=1 to 6, n=0 to 5 o=0 to 5 and m+n+o=6, (iii) oligosilanes are selected from the group consisting of linear or branched oligosilanes of the general empirical formula (III)
Me.sub.pSi.sub.qH.sub.rCl.sub.s  (III), wherein q=3-7 p=q to (2q+2) r, s=0 to (q+2) r+s=(2q+2)−p, (iv) carbodisilanes are selected from the group consisting of the general formula (IV)
(Me.sub.aSiH.sub.bCl.sub.e)—CH.sub.2-(Me.sub.cSiH.sub.dCl.sub.f)  (IV) wherein a, c are independently of each other 1 to 3, b, d are independently from each other 0 to 2 e, f are independently from each other 0 to 2, a+b+e=3, c+d+f=3 and, wherein the process further comprises the step of separating the LiCl formed and the step of regeneration of LiH from the separated LiCl, and wherein the process is conducted at a temperature of from about −40° C. to about 250° C. and wherein the hydrogenation reaction a), the redistribution reaction b) and the cleavage reaction c) are carried out simultaneously.

2. A process according to claim 1, wherein the silane substrate is consists of: (i) monosilanes, (ii) disilanes, (iii) oligosilanes, or (iv) carbodisilanes.

3. The process of claim 1, wherein (i) the monosilanes are selected from the group consisting of formulas: MeSiCl.sub.3, Me.sub.2SiCl.sub.2, Me.sub.3SiCl, MeSiHCl.sub.2, Me.sub.2SiHCl, MeSiH.sub.2Cl, MeSiH.sub.3, Me.sub.2SiH.sub.2 and Me.sub.3SiH, (ii) the disilanes are selected from the group consisting of formulas: Cl.sub.2MeSi—SiMeCl.sub.2, Cl.sub.2MeSi—SiMe.sub.2Cl, Cl.sub.2MeSi—SiMe.sub.3 ClMe.sub.2Si—SiMe.sub.2Cl, Me.sub.3Si—SiMe.sub.2Cl, HMe.sub.2Si—SiMe.sub.2Cl, H.sub.2MeSi—SiMeClH, HClMeSi—SiMeClH, ClHMeSi—SiMeCl.sub.2, H.sub.2MeSi—SiMeCl.sub.2, HMe.sub.2Si—SiMeCl.sub.2, ClMe.sub.2Si—SiMeH.sub.2, HMe.sub.2Si—SiMeClH, ClMe.sub.2Si—SiMeClH, Me.sub.3Si—SiMeClH, HMe.sub.2Si—SiMe.sub.2H, H.sub.2MeSi—SiMeH.sub.2, HMe.sub.2Si—SiMeH.sub.2, Me.sub.3Si—SiMeH.sub.2 and Me.sub.3Si—SiMe.sub.2H, (iii) oligosilanes are selected from the group consisting of formulas: ClMe.sub.2Si—SiMe.sub.2-SiMe.sub.2Cl, ClMe.sub.2Si—SiMe.sub.2-SiMe.sub.2-SiMe.sub.2Cl, (ClMe.sub.2Si).sub.3SiMe, (Cl.sub.2MeSi).sub.2SiMeCl, (Cl.sub.2MeSi).sub.3SiMe, (Cl.sub.2MeSi).sub.2SiMe-SiClMe-SiCl.sub.2Me, [(Cl.sub.2MeSi).sub.2SiMe].sub.2, [(Cl.sub.2MeSi).sub.2SiMe].sub.2SiClMe, (Cl.sub.2MeSi).sub.2SiMe-SiMe.sub.2Cl, ClMe.sub.2Si—SiMe.sub.2SiMe.sub.2H, HMe.sub.2Si—SiMe.sub.2-SiMe.sub.2H, HMe.sub.2Si—SiMe.sub.2-SiMe.sub.2-SiMe.sub.2H, (HMe.sub.2Si).sub.3SiMe, (H.sub.2MeSi).sub.2SiMeH, (H.sub.2MeSi).sub.3SiMe, (H2MeSi)2SiMe-SiHMe-SiH2Me, [(H2MeSi)2SiMe]2, [(H2MeSi)2SiMe]2SiHMe and (H2MeSi)2SiMe-SiMe2H, (iv) the carbodisilanes are selected from the group consisting of formulas: Cl.sub.2MeSi—CH.sub.2—SiMeCl.sub.2, ClMe.sub.2Si—CH.sub.2—SiMeCl.sub.2, ClMe.sub.2Si—CH.sub.2—SiMe.sub.2Cl, Me.sub.3Si—CH.sub.2—SiMeCl.sub.2 Me.sub.3Si—CH.sub.2—SiMe.sub.2Cl, HClMeSi—CH.sub.2—SiMeClH, HMe.sub.2Si—CH.sub.2—SiMeCl.sub.2, HMe.sub.2Si—CH.sub.2—SiMe.sub.2Cl, Me.sub.3Si—CH.sub.2—SiMeClH, H.sub.2MeSi—CH.sub.2—SiMeH.sub.2, HMe.sub.2Si—CH.sub.2—SiMeH.sub.2, HMe.sub.2Si—CH.sub.2—SiMe.sub.2H, Me.sub.3Si—CH.sub.2—SiMeH.sub.2, and Me.sub.3Si—CH.sub.2—SiMe.sub.2H, with the proviso that at least one of the silanes used in the process has at least one chloro substituent.

4. The process of claim 1, wherein the silane substrate comprises at least one silane selected from the group consisting of MeSiCl.sub.3, Me.sub.2SiCl.sub.2, Me.sub.3SiCl, MeSiHCl.sub.2, Me.sub.2SiHCl, MeSiH.sub.2Cl, MeSiH.sub.3, Me.sub.2SiH.sub.2, Me.sub.3SiH, Cl.sub.2MeSi—SiMeCl.sub.2, Cl.sub.2MeSi—SiMe.sub.2Cl, Cl.sub.2MeSi—SiMe.sub.3, ClMe.sub.2Si—SiMe.sub.2Cl, Me.sub.3Si—SiMe.sub.2Cl, Cl.sub.2MeSi—CH.sub.2—SiMeCl.sub.2, ClMe.sub.2Si—CH.sub.2—SiMeCl.sub.2, ClMe.sub.2Si—CH.sub.2—SiMe.sub.2Cl, Me.sub.3Si—CH.sub.2—SiMeCl.sub.2 and Me.sub.3Si—CH.sub.2—SiMe.sub.2Cl.

5. The process of claim 1, wherein the redistribution reaction of silanes comprises the comproportionation of two different methylsilanes, leading to the formation of one specific chlorohydridomethylsilane.

6. The process of claim 1, wherein the redistribution reaction b) is carried out in the presence of at least one redistribution catalyst.

7. The process of claim 1, wherein the cleavage reaction c) is carried out in the presence of at least one cleavage catalyst.

8. The process of claim 1, wherein the silane substrate comprises a product of the Müller-Rochow Direct Process.

9. The process, of claim 1, wherein the silane substrate comprises the entire product of the Müller-Rochow Direct Process or a part (fraction) of the product of the Müller-Rochow Direct Process.

10. The process of claim 1, wherein the silane substrate comprises the monosilane fraction of the Müller-Rochow Direct Process product.

11. The process, of claim 1, wherein the silane substrate is the higher silane fraction (silanes having ≥2 Si atoms) of the Müller-Rochow Direct Process product.

12. The process of claim 6, wherein the redistribution catalyst is selected from the group consisting of: R.sub.4PCl, wherein R is hydrogen or an organyl group, which can be the same or different, triorganophosphines, wherein R is hydrogen or an organyl group, triorganoamines, wherein R is an organyl group, N-heterocyclic amines, quaternary ammonium compounds, an alkali metal halide, an alkaline earth metal halide, an alkali metal hydride, and an alkaline earth metal hydride.

13. The process of claim 6, wherein the cleavage catalyst is selected from the group consisting of: a quaternary Group 15 onium compound R.sub.4QX, wherein each R is independently a hydrogen or an organyl group, Q is phosphorus, arsenic, antimony or bismuth, and X is a halide selected from the group consisting of F, Cl, Br and I, a heterocyclic amine, a heterocyclic ammonium halide, a mixture of R.sub.3P and RX, wherein R is as defined above, and X is as defined above, alkali metal halide, an alkaline earth metal halide, an alkali metal hydride, alkaline earth metal hydride or mixtures thereof, optionally in the presence of hydrogen chloride (HCl).

Description

EXAMPLES

(1) The present invention is further illustrated by the following examples, without being limited thereto.

General

(2) Various silane substrates as formed in the Direct Process of formation of methylchlorosilanes were reacted. All reactants and solvents used were carefully dried according to procedures known from literature. The reactions investigated were generally performed in sealed NMR tubes first to prevent evaporation of low boiling reaction products, and to elucidate the reaction conditions (temperature, time) for silicon-silicon bond cleavage. Subsequently, these conditions were exemplarily transferred to a preparative scale: (i) in a closed system, preferably a sealed glass ampoule to avoid evaporation of low boiling reaction educts and products, e.g. organo chloro- and organo hydridosilanes. After the reactions were completed, the ampoule was frozen opened under vacuum and products formed were isolated by combined condensation/disitillation procedures. (ii) in an open system, preferably a multi-necked flask, equipped with a magnetic stirrer, thermometer, dropping funnel, and a reflux condenser that was connected with a cooling trap to collect low boiling reaction products. Products formed were isolated by combined condensation/distillation procedures. Products were analyzed and characterized by standard procedures, especially by NMR spectroscopy and GC/MS analyses.

(3) Identification of Products

(4) Products were analyzed by .sup.1H, .sup.29Si and .sup.1H-.sup.29Si-HSQC NMR spectroscopy. The spectra were recorded on a Bruker AV-500 spectrometer equipped with a Prodigy BBO 500 S1 probe. .sup.1H-NMR spectra were calibrated to the residual solvent proton resonance ([D.sub.6]benzene δ.sub.H=7.16 ppm). Product identification was additionally supported by GC-MS analyses and verified identification of the main products. GC-MS analyses were measured with a Thermo Scientific Trace GC Ultra coupled with an ITQ 900MS mass spectrometer. The stationary phase (Machery-Nagel PERMABOND Silane) had a length of 50 m with an inner diameter of 0.32 mm. 1 μl of analyte solution was injected, 1/25 thereof was transferred onto the column with a flow rate of 1.7 mL/min carried by helium gas. The temperature of the column was first kept at 50° C. for 10 minutes. Temperature was then elevated at a rate of 20° C./min up to 250° C. and held at that temperature for another 40 minutes. After exiting the column, substances were ionized with 70 eV and cationic fragments were measured within a range of 34-600 m/z (mass per charge). Product mixtures were diluted with benzene prior to the measurement.

(5) The characteristic .sup.29Si-NMR chemical shifts and coupling constants .sup.1J{.sup.29Si-.sup.1H} for the starting materials reacted with the alkali- and alkaline earth metal salts and the products formed, are listed in Table 1.

(6) TABLE-US-00001 TABLE 1 Identification of starting materials and products Compound δ .sup.29Si [ppm] .sup.1J (Si—H) [Hz] No. Si.sup.A—Si.sup.B A B A B 1 Cl.sub.2MeSi—SiMeCl.sub.2 17.5 — 2 ClMe.sub.2Si—SiMeCl.sub.2 15.0 24.6 — 3 ClMe.sub.2Si—SiMe.sub.2Cl 17.1 — 4 Me.sub.3Si—SiMeCl.sub.2 34.0 −14.1 — 5 Me.sub.3Si—SiMe.sub.2Cl 22.5 −18.6 — 6 Me.sub.3Si—SiMe.sub.3 −20.1 — 7 MeSiCl.sub.3 12.3 — 8 MeSiHCl.sub.2 10.9 280.2 9 MeSiH.sub.2Cl −11.4 229.4 10 MeSiH.sub.3 −65.5 194.1 11 Me.sub.2SiCl.sub.2 31.5 — 12 Me.sub.2SiHCl 11.0 223.3 13 Me.sub.2SiH.sub.2 −38.1 187.6 14 Me.sub.3SiCl 30.1 — 15 Me.sub.3SiH −16.6 182.9 16 H.sub.2MeSi—SiMeH.sub.2 −67.8 185.8 17 HMe.sub.2Si—SiMeH.sub.2 −39.9 −66.7 180.9 180.5 18 HMe.sub.2Si—SiMe.sub.2H −39.5 177.5 19 Me.sub.3Si—SiMeH.sub.2 −18.3 −66.0 — 177.7 20 Me.sub.3Si—SiMe.sub.2H −19.2 −39.4 — 172.5 21 ClMe.sub.2Si—SiMe.sub.2H 23.0 −39.0 — 176.4 22 Cl.sub.2MeSi—SiMeClH 23.8 −6.7 — 227.4 23 HClMeSi—SiMeClH −3.9 −4.3 211.7 24 Cl.sub.2MeSi—SiMeH.sub.2 32.1 −61.4 — 196.7 25 HClMeSi—SiMeH.sub.2 0.6 −64.7 215.0 203.3 26 ClMe.sub.2Si—SiMeClH 17.6 −3.7 — 221.3 27 Cl.sub.2MeSi—SiMe.sub.2H 33.8 −35.5 — 191.3 28 ClMe.sub.2Si—SiMeH.sub.2 22.6 −64.6 — 195.6 29 HMe.sub.2Si—SiMeClH 1.83 −38.2 181.3 198.4 30 Cl.sub.2MeSi—CH.sub.2—SiMeCl.sub.2 26.2 — 31 ClMe.sub.2Si—CH.sub.2—SiMeCl.sub.2 28.1 25.7 — — 32 ClMe.sub.2Si—CH.sub.2—SiMe.sub.2Cl 28.3 — 33 Me.sub.3Si—CH.sub.2—SiMeCl.sub.2 30.6 −0.5 — — 34 Me.sub.3Si—CH.sub.2—SiMe.sub.2Cl 30.0 −0.4 — — 35 Me.sub.3Si—CH.sub.2—SiMe.sub.3 −0.5 —

Example 1

(7) LiH (3.0 mmol), Me.sub.2SiCl.sub.2 (1.7 mmol), tetraglyme (0.35 ml) and catalytic amounts of n-Bu.sub.4PCl (0.02 mmol) were placed in an NMR tube cooled to −196° C. (liquid nitrogen). After evacuation the NMR tube was sealed and warmed to r.t. The starting materials reacted upon heating the sample, and the reaction course of the chlorosilane reduction/redistribution reaction was monitored by NMR spectroscopy.

(8) TABLE-US-00002 TABLE 2 80° C., 120° C., 120° C., 120° C., no. silane 0.25 h +2 h +2.5 h +6 h 13 Me.sub.2SiH.sub.2 31 35 47 55 11 Me.sub.2SiCl.sub.2 57 20 7 3 12 Me.sub.2SiHCl 12 45 46 42

(9) As can be seen from Table 2, the formation of hydridosilane (13) was steadily increasing with increasing reaction temperature and time. The maximum molar amount (in %) of chlorosilane 12 (Me.sub.2Si(H)Cl) essentially formed by redistribution of hydridosilane (13) with dichlorosilane 11 is about 46%. At 120° C./10 h the molar amount of Me.sub.2SiCl.sub.2 was reduced to only 3% yield, thus being hardly available for further redistribution with Me.sub.2SiH.sub.2, present in 55 mol-% under these reaction conditions. As mentioned above Me.sub.2SiH.sub.2 can be in turn subjected to a chlorination reaction preferably with ether/HCl or a redistribution reaction with silanes comprising at least one chlorine atom, for which the redistribution catalysts can be used as described above.

Example 2

(10) The reaction was performed in an analogous manner to the reaction of Example 1 except for using diglyme as solvent.

(11) Table 3 covers the experimental findings of running the reaction as described. The yield of the target compound 12 was 55% at 120° C./+2 h.

(12) TABLE-US-00003 TABLE 3 80° C., 120° C., 120° C., 120° C., no. silane 0.25 h +2 h +2.5 h +6 h 13 Me.sub.2SiH.sub.2 37 24 36 45 11 Me.sub.2SiCl.sub.2 51 21 13 5 12 Me.sub.2SiHCl 12 55 51 50

Example 3

(13) In analogy to the reaction of Example 1, MeSiCl.sub.3 (1.7 mmol), tetraglyme (0.35 ml) and catalytic amounts of n-Bu.sub.4PCl (0.02 mmol) were placed in an NMR tube, cooled to −196° C. (liquid nitrogen), then LiH (2.5 mmol) was added; the NMR tube was evacuated, sealed and warmed to r.t. The starting materials reacted upon heating the sample, and the course of the chlorosilane reduction/redistribution reaction was monitored by NMR spectroscopy.

(14) TABLE-US-00004 TABLE 4 80° C., 120° C., 120° C., 120° C., 120° C., no. silane 0.25 h +2 h +2.5 h +6 h +60 h 7 MeSiCl.sub.3 55 33 12 8 3 8 MeSiH.sub.2Cl — — 14 23 32 9 MeSiHCl.sub.2 45 67 74 67 60 10 MeSiH.sub.3 — — — 2 5

(15) As listed in Table 4, the molar amount of methyltrichlorosilane (7) was steadily decreasing with increasing reaction temperatures and reaction times, and the amount of the target compound MeSiHCl.sub.2 (9) increased to 74%, while MeSiH.sub.2Cl (8) was formed in 14% yield at 120° C. (+4.5 h). With prolonged reaction times, chlorosilane 7 was reduced almost quantitatively. With prolonged reaction times at 120° C., the amount of 9 decreased (60%) due to excess LiH, that supported formation of hydridochlorosilanes 8 (32%) and hydridosilane 10 (5%).

Example 4

(16) The reaction was performed in analogy to the reaction of Example 3, but using diglyme as solvent and 2.7 mmol LiH. Table 5 covers the results of running the reaction as described, showing comparable trends and giving similar results as obtained in Example 3. Notably, already with short reaction time, overall hydrogenation is about 90%. The equilibrium between silanes 8 and 9 was shifted with prolonged reaction times, implying targeted product formation by simply controlling the reaction conditions.

(17) TABLE-US-00005 TABLE 5 80° C./0.25 120° C., 120° C., 120° C., no. silane h + 120° C./2 h +2.5 h +6 h +60 h 7 MeSiCl.sub.3 9 5 3 2 8 MeSiH.sub.2Cl 23 28 37 41 9 MeSiHCl.sub.2 66 63 53 48 10 MeSiH.sub.3 2 3 7 9

Example 5

(18) LiH (1.5 mmol), Me.sub.2SiCl.sub.2 (1.6 mmol), diglyme (0.4 ml) and a catalytic amount of n-Bu.sub.4NCl (0.02 mmol) were placed in an NMR tube that was cooled to −196° C. (liquid nitrogen). After evacuation in vacuo the NMR tube was sealed and warmed to r.t. The starting materials reacted upon heating the sample, and the reaction course of the chlorosilane reduction/redistribution reaction was monitored by NMR spectroscopy.

(19) TABLE-US-00006 TABLE 6 120° C., 160° C., no. silane 22 h +40 h 13 Me.sub.2SiH.sub.2 7 10 11 Me.sub.2SiCl.sub.2 42 41 12 Me.sub.2SiHCl 52 49

(20) After 22 h at 120° C. dimethyldichlorosilane was hydrogenated to give dimethylsilane 13 that subsequently redistributed with dimethyldichlorosilane 11 to give Me.sub.2SiHCl (12) in 52% yield. Increasing the reaction temperature and time led to further hydrogenation of chlorosilanes but did not change the product distribution significantly (Table 6).

Example 6

(21) The reaction was performed in an analogous manner to the reaction of Example 5 except for using PPh.sub.3 (0.02 mmol) as a redistribution catalyst.

(22) TABLE-US-00007 TABLE 7 120° C., 160° C., 160° C., no. silane 13 h +22 h +40 h 13 Me.sub.2SiH.sub.2 32 14 11 11 Me.sub.2SiCl.sub.2 66 47 33 12 Me.sub.2SiHCl 2 39 56

(23) As can be seen from Table 7, the formation of Me.sub.2SiHCl (12) was steadily increasing with increasing reaction temperature and time. The maximum amount of chlorosilane 12 essentially formed by redistribution of hydridosilane 13 with dichlorosilane 11 was 56% after 62 h at 160° C.

Example 7

(24) The reaction was performed in analogy to the reaction of Example 5, except for using n-Bu.sub.3P (0.02 mmol) as redistribution catalyst.

(25) TABLE-US-00008 TABLE 8 120° C., 160° C., 160° C., no. silane 13 h +22 h +40 h 13 Me.sub.2SiH.sub.2 34 25 16 11 Me.sub.2SiCl.sub.2 64 48 30 12 Me.sub.2SiHCl 2 27 54

(26) Similar to Example 6, the maximum amount of chlorosilane 12 formed by redistribution was 54% after 62 h at 160° C. (Table 8).

Example 8

(27) The reaction was performed in an analogous manner to the reaction of Example 5 except for using 2-methylimidazole (0.02 mmol) as redistribution catalyst.

(28) TABLE-US-00009 TABLE 9 120° C., 160° C., 200° C., no. silane 13 h +22 h +40 h 13 Me.sub.2SiH.sub.2 34 39 21 11 Me.sub.2SiCl.sub.2 65 57 24 12 Me.sub.2SiHCl 1 4 52 not ident. — 3

(29) In contrast to Example 6 and 7, Me.sub.2SiHCl (12) was formed only in a molar amount of 4% after 22 h/160° C. Increasing the reaction temperature and time to 200° C./40 h finally gave 12 in 52% yield (Table 9).

Example 9

(30) Me.sub.2SiCl.sub.2 (0.8 mmol), Me.sub.2ClSi—SiClMe.sub.2 (0.8 mmol), LiH (2.5 mmol), diglyme (0.4 ml) and catalytic amounts of n-Bu.sub.4PCl (0.04 mmol) were placed in an NMR tube cooled to −196° C. (liquid nitrogen). After evacuation the NMR tube was sealed, warmed and the reaction course was investigated NMR spectroscopically.

(31) TABLE-US-00010 TABLE 10 120° C., 120° C., no. silane 13 h +22 h 13 Me.sub.2SiH.sub.2 17 35 11 Me.sub.2SiCl.sub.2 9 6 12 Me.sub.2SiHCl 44 42 3 (Me.sub.2ClSi).sub.2 9 1 18 (Me.sub.2HSi).sub.2 4 6 21 Me.sub.2ClSi—SiHMe.sub.2 17 5 trisilanes — 5

(32) At 120° C./13 h Me.sub.2ClSi—SiClMe.sub.2 was cleaved as well as partially and fully hydrogenated to give compound 18 in 4% and compound 21 in 17% yield. Targeted product Me.sub.2SiHCl (12) was formed in 44% besides Me.sub.2SiH.sub.2 (13) in 17% yield. Prolonged reaction times (+22 h) led to further hydrogenation by LiH to give hydridosilane 13 in a molar amount of 35%, while targeted product 12 was reduced to 42%. The amount of disilanes 3 and 21 decreased to 1% and 5% yield, respectively, while the molar amount of the fully hydrogenated disilane 18 increased slightly (6%). Trisilanes were formed in 5% (Table 10).

Example 10

(33) MeCl.sub.2Si—SiCl.sub.2Me (0.6 mmol), MeSiCl.sub.3 (0.6 mmol), LiH (1.5 mmol), diglyme (0.4 ml) and PPh.sub.3 (0.05 mmol) as redistribution catalyst were placed in an NMR tube cooled to −196° C. (liquid nitrogen). After evacuation the NMR tube was sealed, warmed and the reaction course was investigated NMR spectroscopically.

(34) TABLE-US-00011 TABLE 11 160° C., 220° C., no. silane 16 h +15 h 7 MeSiCl.sub.3 42 29 8 MeSiH.sub.2Cl 8 11 9 MeSiHCl.sub.2 50 56 not ident. — 4

(35) After 16 h at 160° C. the starting disilane MeCl.sub.2Si—SiCl.sub.2Me (1) was quantitatively cleaved and via redistribution reactions the targeted products MeSiHCl.sub.2 (8) and MeSiH.sub.2Cl (9) were formed in 50% and 8% yield, respectively. With prolonged reaction times (+15 h) at 220° C. the molar amounts of compounds 8 and 9 were further increased to 56% and 11%, while not identified products were formed in a molar amount of 4% (Table 11).

Example 11

(36) 0.6 mmol of a complex mixture of chlorocarbodisilanes (carbodisilane distribution is listed in Table 12), Me.sub.2SiCl.sub.2 (0.8 mmol), LiH (1.6 mmol), n-Bu.sub.3P (0.05 mmol) and diglyme (0.3 ml) were placed in a cooled NMR tube (−196° C.). After evacuation in vacuo the NMR tube was sealed and warmed to r.t. The starting materials reacted upon heating the sample, and the reaction course of the chlorosilane reduction/redistribution reaction was monitored by NMR spectroscopy.

(37) TABLE-US-00012 TABLE 12 no. silane educt (%) 30 (Cl.sub.2MeSi).sub.2—CH.sub.2 45 31 ClMe.sub.2Si—CH.sub.2—SiMeCl.sub.2 31 32 (Me.sub.2ClSi).sub.2—CH.sub.2 14 34 Me.sub.3Si—CH.sub.2—SiMe.sub.2Cl 10

(38) TABLE-US-00013 TABLE 13 160° C., 220° C., no. silane 16 h +15 h 13 Me.sub.2SiH.sub.2 34 5 11 Me.sub.2SiCl.sub.2 36 25 12 Me.sub.2SiHCl 8 34 9 MeSiH.sub.2Cl — 7 8 MeSiHCl.sub.2 — 7 10 MeSiH.sub.3 2 9 carbodisilanes 20 13

(39) After 16 h at 160° C. the targeted product Me.sub.2SiHCl (12) as well as dimethylsilane were formed in 8% and 34% yield, respectively. Hydrogenation and cleavage of chlorocarbodisilanes gave methylsilane 10 in 2% yield. With prolonged reaction times (+15 h) at 220° C. the molar amount of 12 increased to 34%, while that of Me.sub.2SiH.sub.2 (13) decreased (5%) due to redistribution reactions with chlorosilanes. Carbodisilanes were further cleaved (13% remained) to give silanes 8, 9 and 10 in 7%, 7% and 9% yield, respectively (Table 13).

Example 12

(40) MeSiCl.sub.3 (1.7 mmol) and tetraglyme (0.35 ml) were placed in an NMR tube, cooled to −196° C. (liquid nitrogen), then LiH (2.5 mmol) was added; the NMR tube was evacuated, sealed and warmed to r.t. The starting materials reacted upon heating the sample, and the course of the chlorosilane reduction/redistribution reaction was monitored by NMR spectroscopy. As listed in Table 14, the target compounds MeSiHCl.sub.2 (8, 11%) and MeSiH.sub.2Cl (9, 28%) were formed at 160° C., but required longer reaction times.

(41) TABLE-US-00014 TABLE 14 60° C., 100° C., 120° C., 160° C., no. silane 2 min +19 h +40 h +40 h 7 MeSiCl.sub.3 75 60 54 36 9 MeSiH.sub.2Cl 2 6 10 28 8 MeSiHCl.sub.2 1 4 5 11 10 MeSiH.sub.3 22 30 31 25

Example 13

(42) Example for the Subsequent Treatment of Perhydrated by-Products, Such as Me.sub.2SiH.sub.2, by Chlorination with HCl in Ether Solvents

(43) Upon warming Me.sub.2SiH.sub.2 to r.t. it was evaporated into a 1 L flask filled with the HCl/diglyme reagent (170 g, 4.7 mol of HCl in 540 ml diglyme) that was cooled to −45° C. After completion (1.5 h) the reaction mixture was stirred for 4 h and then allowed to warm to 15° C. over a period of 8 hours. The HCl/diglyme flask was connected with a cooling trap (−78° C.) and after the overall reaction time of 12 hours a mixture of 16.85 g (0.28 mol) Me.sub.2SiH.sub.2, 0.83 g (9 mmol) Me.sub.2SiHCl and 0.13 g (3 mmol) of methyl chloride were collected. Volatile compounds of the HCl/diglyme solution were condensed under vacuum in a cooling trap (about −196° C.) that was connected to another trap cooled to about −78° C. The condensed mixture (about −196° C.) was allowed to warm to r.t. at normal pressure (about 1013 mbar) separating dimethylchlorosilane formed from gaseous hydrogen chloride: Me.sub.2SiHCl was collected in the −78° C. cooling trap while excess HCl was directly recycled by evaporation into a 1 L flask filled with diglyme used for the chlorination reaction at the beginning. The Me.sub.2SiHCl collected in the −78° C. trap was condensed into an ampoule with Young-valve to give 59 g (0.62 mol) of Me.sub.2SiHCl besides traces of methyl chloride and Me.sub.2SiCl.sub.2, obviously formed by double chlorination of Me.sub.2SiH.sub.2.

(44) Me.sub.2SiH.sub.2, collected in the −78° C. cooling trap after chlorination reaction (16.85 g, see above), was additionally evaporated into the (recycled) HCl/diglyme mixture and reacted and worked up as described before, giving 25 g (0.27 mol) Me.sub.2SiHCl, contaminated with traces of methyl chloride. Combining both Me.sub.2SiHCl fractions and final distillation over a 50 cm Vigreux column at normal pressure gave 74 g (0.89 mol) of Me.sub.2SiHCl (b.p.: 35° C.), in a yield of 99% for the chlorination step.

Example 14

(45) A mixture of 112 mg highly chlorinated disilanes 69 mol % Cl.sub.2MeSi—SiMeCl.sub.2, 26 mol % ClMe.sub.2Si—SiMeCl.sub.2, 4 mol % ClMe.sub.2Si—SiMe.sub.2Cl and 1 mol % Me.sub.3Si—SiMeCl.sub.2 were reacted with 8.1 mg LiH (50 mol %, in relation to chlorine content in the mixture) in diglyme as solvent. Reduction, redistribution and cleavage of chloro-mono- and disilanes started at r.t. as indicated by warming up of the reaction mixture. The products formed are listed in Table 15. The cleavage of disilanes was nearly quantitative, only highly methylated disilane ClMe.sub.2Si—SiMe.sub.2Cl remained in traces (˜1%). Monosilane MeSiH.sub.2Cl is the main product followed by monosilane 8.

(46) TABLE-US-00015 TABLE 15 no. silane mol % 8 MeSiHCl.sub.2 21 12 Me.sub.2SiHCl 9 9 MeSiH.sub.2Cl 33 11 Me.sub.2SiCl.sub.2 19 14 Me.sub.3SiCl 2 7 MeSiCl.sub.3 2 10 MeSiH.sub.3 13 3 ClMe.sub.2Si—SiMe.sub.2Cl 1

Example 15

(47) Reaction of the methylchlorodisilane mixture (183 mg) of the sample from Example 14 with LiH in diglyme can easily be controlled by the amount of LiH reacted. Reduction of LiH to 41 mol % (10 mg, in relation to chlorine content in the mixture (when compared to Example 14) avoids formation of the low boiling monosilane MeSiH.sub.3, instead dichlorsilanes MeSiHCl.sub.2 and Me.sub.2SiCl.sub.2 became the main products. The overall product composition is listed in Table 16, about 2 mol % disilanes remained unreacted. The reaction occurred at r.t. under self-heating of the sample to about 40° C.

(48) TABLE-US-00016 TABLE 16 no. silane mol % 8 MeSiHCl.sub.2 37 12 Me.sub.2SiHCl 7 9 MeSiH.sub.2Cl 6 11 Me.sub.2SiCl.sub.2 34 14 Me.sub.3SiCl 2 7 MeSiCl.sub.3 11 1 Cl.sub.2MeSi—SiMeCl.sub.2 0.5 3 ClMe.sub.2Si—SiMe.sub.2Cl 1.5

Example 16

(49) The results of Example 15 are further investigated by treating the mixture of disilanes (110 mg-159 mg) of Example 14 with different molar amounts of LiH (25 mol-%, 50 mol-%, 75 mol-%, 100 mol-% and 400 mol-%, in relation to chlorine content in the mixture) in diglyme. All reactions occurred at r.t. with self-heating of the samples. The products formed are listed in Table 17 and demonstrate that after cleavage of the silicon-silicon bonds the resulting chlorinated monosilanes are further transformed into hydrogen-substituted monosilanes by LiH.

(50) The higher the chloro substitution at Si is, the faster hydrogenation occurs: MeSiCl.sub.3>Me.sub.2SiCl.sub.2>Me.sub.3SiCl. The same is true for the only partially hydrated monosilanes MeH.sub.2SiCl>MeSiHCl.sub.2>Me.sub.2SiHCl. Especially the latter reacts very slowly because the molar amount of this chlorosilane remains nearly constant in all reactions performed. With high excess of LiH (about 400 mol %) all chloro substituted monosilanes are completely reacted to the per hydrogenated silanes Me.sub.2SiH.sub.2 (6%) MeSiH.sub.3 (78%) and the per hydrogenated disilanes

(51) H.sub.2MeSi-SiMeH.sub.2, HMe.sub.2Si—SiMeH.sub.2,

(52) HMe.sub.2Si—SiMe.sub.2H and Me.sub.3Si—SiMeH.sub.2.

(53) The results of this series of experiments are listed in the Table 17. In summary, for the synthesis of monohydrated silanes such as MeSiHCl.sub.2 and Me.sub.2SiHCl, LiH should be used in stoichiometric deficit (<about 25 mol %), for an increase of the amount of monosilane MeSiH.sub.2Cl the molar amount of LiH is best about 25 mol-% to about 75 mol %. For a complete formation of perhydrido-methylsilanes (MeSiH.sub.3 and Me.sub.2SiH.sub.2) LiH should be used in excess, but this is not desirable according to the present invention.

(54) TABLE-US-00017 TABLE 17 LiH conc. [ mol %] 25 50 75 100 400 no. silane mol % mol % mol % mol % mol % 8 MeSiHCl.sub.2 30 21 6 2 — 12 Me.sub.2SiHCl 11 13 12 12 — 9 MeSiH.sub.2Cl 18 35 30 24 — 13 Me.sub.2SiH.sub.2 — — 2 3 6 10 MeSiH.sub.3 7 13 41 56 78  11 Me.sub.2SiCl.sub.2 21 15 7 2 — 14 Me.sub.3SiCl 2 2 1 traces — 3 ClMe.sub.2Si—SiMe.sub.2Cl 1 1 1 1 — 16 H.sub.2MeSi—SiMeH.sub.2 — — — traces 8 17 H.sub.2MeSi—SiMe.sub.2H — — — — 5 19 Me.sub.3Si—SiMeH.sub.2 — — — — 2 18 HMe.sub.2Si—SiMe.sub.2H — — — — 1

Example 17

(55) The reaction of a complex mixture (131-238 mg) of mainly highly chlorinated disilanes and monosilanes as displayed in Table 18 was reacted with 41 mol % or 73 mol % LiH (in relation to chlorine content in the mixture), respectively, in diglyme at r.t. with self-heating. The products formed are listed in Table 19 and show that monosilanes are formed in a molar amount of 96%, and 4 mol % of tetramethyldichloro- and pentamethylchlorodisilane remained unreacted. Higher amounts of LiH lead to increasing amounts of hydrogen substituted silanes by Si—Cl.fwdarw.Si—H reduction.

(56) TABLE-US-00018 TABLE 18 no. silane mol % 11 Me.sub.2SiCl.sub.2 7.9 5 Me.sub.3Si—SiMe.sub.2Cl 2.0 3 ClMe.sub.2Si—SiMe.sub.2Cl 3.5 1 Cl.sub.2MeSi—SiMeCl.sub.2 49.5 2 ClMe.sub.2Si—SiMeCl.sub.2 33.7 4 Me.sub.3Si—SiMeCl.sub.2 3.0 6 Me.sub.3Si—SiMe.sub.3 0.4

(57) TABLE-US-00019 TABLE 19 LiH conc. [mol %] 41 73 no. silane mol % mol % 8 MeSiHCl.sub.2 17 11 12 Me.sub.2SiHCl 14 21 9 MeSiH.sub.2Cl 20 26 13 Me.sub.2SiH.sub.2 — 2 10 MeSiH.sub.3 6 16 11 Me.sub.2SiCl.sub.2 35 16 14 Me.sub.3SiCl 4 4 3 ClMe.sub.2Si—SiMe.sub.2Cl 2 2 5 Me.sub.3Si—SiMe.sub.2Cl 2 2 6 Me.sub.3Si—SiMe.sub.3 traces traces

Example 18

(58) For hydrogenation of methylchlorodisilanes tributyltin hydride was used as reducing agent. For the preparation of n-Bu.sub.3SnH see: U. Herzog, G. Roewer and U. Pitzold, Katalytische Hydrierung chlorhaltiger Disilane mit Tributylstannan, J. Organomet. Chem 1995, 494, 143-147.

(59) Disilane (ClMe.sub.2Si—SiMe.sub.2Cl, admixed with 5 mol % Me.sub.3Si—SiMe.sub.2Cl) (4.04 g) was reacted in a 1/1 molar ratio with the tin hydride in diglyme and tetraphenylphosphoniumchloride (Ph.sub.4PCl, 3 w %) as catalyst at r.t. After work up, a mixture of the disilanes ClMe.sub.2Si—SiMe.sub.2Cl (15 mol %), Me.sub.3Si—SiMe.sub.2Cl (4 mol %), ClMe.sub.2Si—SiMe.sub.2H (72 mol %) and Me.sub.3Si—SiMe.sub.2H (9 mol %) was obtained. 200 mg of those disilanes were subsequently reacted with tetrabutylphosphoniumchloride (n-Bu.sub.4PCl, 25 w %) in a sealed NMR tube at 180° C. for 9 h. As listed in Table 20, the hydrido disilane ClMe.sub.2Si—SiMe.sub.2H was nearly completely cleaved into the monosilanes Me.sub.2SiHCl and Me.sub.2SiH.sub.2 that were formed in 68 mol % yield. Chlorosilane Me.sub.3SiCl results from cleavage of the disilane Me.sub.3Si—SiMe.sub.2Cl. Unidentified oligosilanes were detected in small amounts.

(60) TABLE-US-00020 TABLE 20 no. silane mol % 12 Me.sub.2SiHCl 37 13 Me.sub.2SiH.sub.2 31 14 Me.sub.3SiCl 14 11 Me.sub.2SiCl.sub.2 8 15 Me.sub.3SiH 1 educts, oligosilanes 9

(61) The mixture of disilanes ClMe.sub.2Si—SiMe.sub.2Cl (15 mol %), Me.sub.3Si—SiMe.sub.2Cl (4 mol %), ClMe.sub.2Si—SiMe.sub.2H (72 mol %) and Me.sub.3Si—SiMe.sub.2H (9 mol %) as obtained above from hydrogenation (200 mg) was reacted with 2-methylimidazole (2-MIA, 16 w %) in a sealed NMR tube at 220° C. for 9 h. The amount of chlorosilane Me.sub.2SiHCl was smaller than in the reaction in the presence of tetrabutylphosphoniumchloride, the main product obtained was dimethylsilane Me.sub.2SiH.sub.2, followed by Me.sub.3SiCl (13.2 mol %). Remaining disilanes Me.sub.3Si—SiMe.sub.2Cl and Me.sub.3Si—SiMe.sub.2H were 15.0 mol % respectively 8.2 mol %. Notably, perhydrogenated disilane HMe.sub.2Si—SiMe.sub.2H was detected in 1.0 mol % (Table 21).

(62) Prolonged reaction times (69 h) lead to almost quantitative splitting of H-substituted disilanes as well as conversion of tri- and tetrasilanes (ClMe.sub.2Si—SiMe.sub.2-SiMe.sub.2Cl and ClMe.sub.2Si—SiMe.sub.2-SiMe.sub.2-SiMe.sub.2Cl), named in the table as “oligosilanes”, into monomers. Products obtained are listed in Table 22 and prove formation of Me.sub.2SiHCl (˜40 mol %) as main component.

(63) TABLE-US-00021 TABLE 21 no. silane mol % 12 Me.sub.2SiHCl 17.1 13 Me.sub.2SiH.sub.2 31.5 14 Me.sub.3SiCl 13.2 11 Me.sub.2SiCl.sub.2 8.8 21 ClMe.sub.2Si—SiMe.sub.2H 15.0 20 Me.sub.3Si—SiMe.sub.2H 8.2 18 HMe.sub.2Si—SiMe.sub.2H 1.0 oligosilanes 5.2

(64) TABLE-US-00022 TABLE 22 no. silane mol % 12 Me.sub.2SiHCl 39.5 13 Me.sub.2SiH.sub.2 34.0 14 Me.sub.3SiCl 13.4 11 Me.sub.2SiCl.sub.2 7.3 21 ClMe.sub.2Si—SiMe.sub.2H 5.8

Example 19

(65) Hydrogenation Reaction

(66) For simulation of a mono- and disilane fraction obtained from the Müller-Rochow-Direct Process, a mixture (1.10 g) of compounds listed in Table 24, (1.19 g) of monosilane Me.sub.2SiCl.sub.2 and highly chlorinated disilanes listed in Table 25 and (1.07 g) of compounds listed in Table 23 were mixed and reacted with different molar amounts of n-Bu.sub.3SnH to replace 25, 50 and 75 mol % of all chlorine substituents at silicon. After reduction, the products were isolated by condensation/distillation to give the product mixtures IV, V and VI listed in Table 26.

(67) TABLE-US-00023 TABLE 23 no. silane mol % 11 Me.sub.2SiCl.sub.2 12.4 14 Me.sub.3SiCl 2.2 7 MeSiCl.sub.3 11.5 5 Me.sub.3Si—SiMe.sub.2Cl 16.8 3 ClMe.sub.2Si—SiMe.sub.2Cl 22.6 1 Cl.sub.2MeSi—SiMeCl.sub.2 16.2 2 ClMe.sub.2Si—SiMeCl.sub.2 7.1 4 Me.sub.3Si—SiMeCl.sub.2 2.7 6 Me.sub.6Si2 2.4 34 Me.sub.3Si—CH.sub.2—SiMe.sub.2Cl 3.1 30 (Cl.sub.2MeSi).sub.2—CH.sub.2 0.4 31 ClMe.sub.2Si—CH.sub.2—SiMeCl.sub.2 0.9 33 Me.sub.3Si—CH.sub.2—SiMeCl.sub.2 0.4 35 Me.sub.3Si—CH.sub.2—SiMe.sub.3 1.3

(68) TABLE-US-00024 TABLE 24 no. silane mol % 11 Me.sub.2SiCl.sub.2 6.8 14 Me.sub.3SiCl 7.1 7 MeSiCl.sub.3 12.5 12 Me.sub.2SiHCl 4.3 8 MeSiHCl.sub.2 1.4 5 Me.sub.3Si—SiMe.sub.2Cl 3.9 3 (ClMe.sub.2Si).sub.2 17.9 1 (Cl.sub.2MeSi).sub.2 1.4 6 Me.sub.6Si.sub.2 0.2 34 Me.sub.3Si—CH.sub.2—SiMe.sub.2Cl 3.9 32 (ClMe.sub.2Si).sub.2—CH.sub.2 5.2 30 (Cl.sub.2MeSi).sub.2—CH.sub.2 14.7 31 ClMe.sub.2Si—CH.sub.2—SiMeCl.sub.2 11.4 33 Me.sub.3Si—CH.sub.2—SiMeCl.sub.2 1.8 35 Me.sub.3Si—CH.sub.2—SiMe.sub.3 7.5

(69) TABLE-US-00025 TABLE 25 no. silane mol % 11 Me.sub.2SiCl.sub.2 7.9 5 Me.sub.3Si—SiMe.sub.2Cl 2.0 3 ClMe.sub.2Si—SiMe.sub.2Cl 3.5 1 Cl.sub.2MeSi—SiMeCl.sub.2 49.5 2 ClMe.sub.2Si—SiMeCl.sub.2 33.7 4 Me.sub.3Si—SiMeCl.sub.2 3.0 6 Me.sub.3Si—SiMe.sub.3 0.4

(70) TABLE-US-00026 TABLE 26 sample IV sample V sample VI no. silane mol % mol % mol % 3 ClMe.sub.2Si—SiMe.sub.2Cl 18 9 7 11 Me.sub.2SiCl.sub.2 18 20  27  5 Me.sub.5Si.sub.2Cl 16 23  28  7 MeSiCl.sub.3 13 7 9 16 H.sub.2MeSi—SiMeH.sub.2 9 18  — 2 ClMe.sub.2Si—SiMeCl.sub.2 4 — — 33 Cl.sub.2MeSi—CH.sub.2—SiMe.sub.3 4 2 3 9 MeSiH.sub.2Cl 3 — — 24 H.sub.2MeSi—SiMeCl.sub.2 3 3 1 17 HMe.sub.2Si—SiMeH.sub.2 3 2 1 6 Me.sub.3Si—SiMe.sub.3 2 5 4 31 ClMe.sub.2Si—CH.sub.2—SiMeCl.sub.2 2 2 6 4 Me.sub.3Si—SiMeCl.sub.2 1 2 4 18 HMe.sub.2Si—SiMe.sub.2H 1 1 2 30 Cl.sub.2MeSi—CH.sub.2—SiMeCl.sub.2 1 3 2 31 ClMe.sub.2Si—CH.sub.2—SiMe.sub.2Cl 1 2 4 34 ClMe.sub.2Si—CH.sub.2—SiMe.sub.3 1 1 3

(71) Redistribution and Cleavage Reaction

(72) Redistribution and cleavage reactions with the mixture of sample IV of table 26 (280 mg) were performed with n-Bu.sub.4PCl (6 w %) in a sealed NMR tube. NMR measurements were taken at r.t., 140° C. (+23 h) and 220° C. (+16 h). Cleavage reactions already started at r.t. and only traces of Me.sub.3Si—SiMe.sub.3 (˜1 mol %) remained unreacted at 220° C. (Table 27).

(73) TABLE-US-00027 TABLE 27 r.t./1 h 140° C./+23 h 220° C./+16 h no. silane mol % mol % mol % 3 ClMe.sub.2Si—SiMe.sub.2Cl 12.1 — 12 Me.sub.2SiHCl 16.5 20.8 21.6 14 Me.sub.3SiCl 1.1 5.0 11.3 11 Me.sub.2SiCl.sub.2 10.1 37.5 40.2 7 MeSiCl.sub.3 — — — 8 MeSiHCl.sub.2 16.7 10.2 7.4 9 MeSiH.sub.2Cl 14.4 11.1 11.3 13 Me.sub.2SiH.sub.2 — — 1.9 10 MeSiH.sub.3 8.8 5.6 2.7 6 Me.sub.3Si—SiMe.sub.3 0.9 0.6 1.1 5 Me.sub.3Si—SiMe.sub.2Cl 7.5 2.8 — carbodisilanes 11.9 6.4 2.5

(74) In Table 28 the results of the comparable cleavage and redistribution reactions of samples V and VI are listed.

(75) TABLE-US-00028 TABLE 28 sample V sample VI r.t. 140° C. 220° C. r.t. 140° C. 220° C. 1 h +23 h +16 h 1 h +23 h +16 h no. silane mol % mol % mol % mol % mol % mol % 3 ClMe.sub.2Si—SiMe.sub.2Cl 13.1 — — 18.1 — — 12 Me.sub.2SiHCl 18.6 36.4 29.7 14.3 29.5 27.3 14 Me.sub.3SiCl 1.6 11.3 17.4 2.6 13.6 22.9 11 Me.sub.2SiCl.sub.2 11.3 28.9 29.2 15.4 37.8 37.2 8 MeSiHCl.sub.2 6.2 1.5 2.0 1.1 0.8 1.2 9 MeSiH.sub.2Cl 6.3 1.6 4.3 0.7 — 2.7 13 Me.sub.2SiH.sub.2 1.1 2.5 7.2 2.5 1.5 2.3 10 MeSiH.sub.3 11.4 5.4 6.9 5.2 2.3 1.7 6 Me.sub.3Si—SiMe.sub.3 1.3 2.0 1.2 2.0 2.6 1.3 5 Me.sub.3Si—SiMe.sub.2Cl 16.9 2.4 — 19.7 1.5 — carbodisilanes 12.2 8.0 2.1 18.4 10.4 3.4

(76) From reactions of samples IV-VI it is obvious that with increasing replacement of Cl against H in the methylchlorodisilanes MenSi.sub.2Cl.sub.6-n with Cl≥3, the partial hydrido substituted disilanes were cleaved significantly faster. Cleavage of disilanes with Me≥4 (partial or perhydrogenated) required higher temperatures. At about 140° C. mainly the chlorosilanes Me.sub.2SiCl.sub.2, Me.sub.3SiCl, Me.sub.2SiHCl and MeSiHCl.sub.2 were formed. Investigation of the reactions by .sup.31P-NMR spectroscopy proved the activity of n-Bu.sub.4PCl as real catalyst, only at 220° C. and higher, the latter is completely reacted to give n-Bu.sub.3P, traces of n-Bu.sub.2PH and 1-but-ene, and hydrogen chloride that is responsible for the final formation of H/Cl substituted monosilanes.

Example 20

(77) In a 50 ml flask, a mixture of disilanes Cl.sub.2MeSi—SiMeCl.sub.2 (69 mol %), ClMe.sub.2Si—SiMeCl.sub.2 (26 mol %), ClMe.sub.2Si—SiMe.sub.2Cl (4 mol %) and Me.sub.3Si—SiMeCl.sub.2 (1 mol %) (244 mg) was reacted with Ph.sub.4PCl (25.3 mg) and LiH (202 mg) in 0.5 mL of diglyme. Already at r.t. 75 mol % of monosilanes were formed, with compound 8 obtained in an amount of 40 mol %. 25 mol % of disilanes remained uncleaved, 10 mol % of those were reduced (SiCl—SiH) (Table 29). MeSiH.sub.3 that might have been formed evaporated in the open system due to its low boiling point (−57° C.). That is why the same disilane mixture (122 mg) was reacted with the catalyst/LiH (1 w %/4 w %) in a sealed NMR tube at r.t. In this case monosilane 10 was detected in 13 mol % yield, the compound 8 was formed in 21 mol % and compound 9 in 33 mol % yield.

(78) TABLE-US-00029 TABLE 29 no. silane mol % 8 MeSiHCl.sub.2 40 12 Me.sub.2SiHCl 9 9 MeSiH.sub.2Cl 10 11 Me.sub.2SiCl.sub.2 10 14 Me.sub.3SiCl 2 7 MeSiCl.sub.3 4 1 Cl.sub.2MeSi—SiMeCl.sub.2 4 3 ClMe.sub.2Si—SiMe.sub.2Cl 1 2 ClMe.sub.2Si—SiMeCl.sub.2 9 4 Me.sub.3Si—SiMeCl.sub.2 1 24 MeH.sub.2Si—SiMeCl.sub.2 2 25 MeH.sub.2Si—SiMeHCl 6 17 HMe.sub.2Si—SiMeH.sub.2 1 16 MeH.sub.2Si—SiMeH.sub.2 1

Example 21

(79) This Example 21 illustrates the desirable changes in composition of the product from the Rochow-Müller Direct Synthesis brought about by treating the crude methylchlorosilane mixture with LiH. Consider that the Rochow-Müller Direct Synthesis is occurring at 290° C./4 atm in a commercial-scale fluidized-bed reactor containing about 45 metric tons copper-activated silicon. Silicon conversion is 4.5%/h, which yields about 9300 kg/h methylchlorosilane crude. All, or a portion, of this crude is treated with LiH to increase formation of methylchlorohydridosilanes, particularly Me.sub.2SiHCl.

(80) Table 30 lists compositions of two samples of the crude methylchlorosilanes, as well as the quantities (in grams per metric ton) of each component. Molar amounts per metric ton and the total moles of chloride are shown in Table 31. These data enable calculation of the molar and gravimetric amounts of LiH required to produce desired quantities of methylchlorohydridosilanes.

(81) TABLE-US-00030 TABLE 30 Gravimetric Composition of Products from Rochow - Müller Direct Synthesis SAMPLE A SAMPLE B COMPOUND wt % g/MT wt % g/MT (CH.sub.3).sub.4Si Trace Trace HSiCl.sub.3 Trace Trace (CH.sub.3).sub.2SiHCl (M2H) 0.09 901.35 1.10 11024.2 CH.sub.3SiHCl.sub.2 (MH) 1.34 13420.1 4.69 46902.96 (CH.sub.3).sub.3SiCl (M) 1.76 17626.4 2.05 20545.1 CH.sub.3SiCl.sub.3 (T) 3.96 39559.25 5.17 51713.52 (CH.sub.3).sub.2SiCl.sub.2 (D) 90.19 901850.75 82.87 828719.18 (CH.sub.3).sub.3SiSi(CH.sub.3).sub.3 0.01 90.16 0.01 123.71 (CH.sub.3).sub.3SiSi(CH.sub.3).sub.2Cl 0.05 452.04 0.06 620.28 Cl(CH.sub.3).sub.2SiSi(CH.sub.3).sub.2Cl 0.09 876.33 0.12 1202.49 (CH.sub.3).sub.3SiSi(CH.sub.3)Cl.sub.2 0.07 737.97 0.10 1012.62 Cl(CH.sub.3).sub.2SiSi(CH.sub.3)Cl.sub.2 0.94 9386.70 1.29 12880.25 Cl.sub.2(CH.sub.3)SiSi(CH.sub.3)Cl.sub.2 1.51 15056.80 2.07 20660.65 T/D 0.044 0.062 MT = Metric ton (1000 kg)

(82) Here, it is useful to recall that methylchlorodisilanes are reduced and cleaved by LiH that the order of reactivity of the methylchlorosilanes with LiH is CH.sub.3SiCl.sub.3>(CH.sub.3).sub.2SiCl.sub.2>(CH.sub.3).sub.3SiCl and CH.sub.3SiH.sub.2Cl>CH.sub.3SiHCl.sub.2>CH.sub.3SiCl.sub.3 and (CH.sub.3).sub.2SiHCl>(CH.sub.3).sub.2SiCl.sub.2

(83) TABLE-US-00031 TABLE 31 Molar Composition of Products from Rochow - Müller Direct Synthesis SAMPLE A, SAMPLE B, COMPOUND mol/MT mol/MT (CH.sub.3).sub.2SiHCl (M2H) 9.53 116.51 CH.sub.3SiHCl.sub.2 (MH) 116.67 407.75 (CH.sub.3).sub.3SiCl (M) 162.25 189.11 CH.sub.3SiCl.sub.3 (T) 264.65 345.96 (CH.sub.3).sub.2SiCl.sub.2 (D) 6987.84 6421.19 (CH.sub.3).sub.3SiSi(CH.sub.3).sub.3 0.62 0.85 (CH.sub.3).sub.3SiSi(CH.sub.3).sub.2Cl 2.71 3.72 Cl(CH.sub.3).sub.2SiSi(CH.sub.3).sub.2Cl 4.68 6.42 (CH.sub.3).sub.3SiSi(CH.sub.3)Cl.sub.2 3.94 5.41 Cl(CH.sub.3).sub.2SiSi(CH.sub.3)Cl.sub.2 45.21 62.04 Cl.sub.2(CH.sub.3)SiSi(CH.sub.3)Cl.sub.2 66.03 90.61 TOTAL CHLORIDE, mol/MT 15351.56 14645.26 LiH (g) for 55 mol % Use 67125 64036 LiH (g) for 110 mol % Use 134249 128073

(84) The remaining calculations are based on the use of 67 kg LiH (value from Table 31, row 14) to treat 1 metric ton of MCS crude having the compositions shown in Table 30.

(85) TABLE-US-00032 TABLE 32 Reduction of Methylchlorosilanes by LiH PRODUCTS FORMED. DATA IN mol % SILANE LiH, mol % (CH.sub.3).sub.3SiCl (CH.sub.3).sub.3SiH (CH.sub.3).sub.3SiCl 55 50 50  110   0 100  (CH.sub.3).sub.2SiCl.sub.2 (CH.sub.3).sub.2SiHCl (CH.sub.3).sub.2SiH.sub.2 (CH.sub.3).sub.2SiCl.sub.2 55 48 4 48  110   0 0 100  CH.sub.3SiCl.sub.3 CH.sub.3SiHCl.sub.2 CH.sub.3SiH.sub.2Cl CH.sub.3SiH.sub.3 CH.sub.3SiCl.sub.3 55 49 1 2  48 110   0 0 0 100

(86) .sup.29Si NMR spectroscopy was used to obtain the data disclosed in Tables 32 on the reaction of individual methylchlorosilanes with LiH. LiH cleavage of the individual methylchlorodisilanes was also studied by .sup.29Si NMR spectroscopy. The data are displayed in Table 33.

(87) TABLE-US-00033 TABLE 33 Cleavage of individual methylchlorodisilanes by LiH REACTION PRODUCTS FORMED. DATA IN mol % DISILANE WITH LiH, % (CH.sub.3).sub.3SiX (CH.sub.3).sub.2SiX.sub.2 CH.sub.3S1X.sub.3 (CH.sub.3).sub.3SiSi(CH.sub.3).sub.2Cl  5* 95 5 Cl(CH.sub.3).sub.2SiSi(CH.sub.3).sub.2Cl  10* 5 95 (CH.sub.3).sub.3SiSi(CH.sub.3)Cl.sub.2 75 90 10 Cl(CH.sub.3).sub.2SiSi(CH.sub.3)Cl.sub.2 75 90 10 Cl.sub.2(CH.sub.3)SiSi(CH.sub.3)Cl.sub.2 80 1 99 *Highly methylated disilanes react only to a limited extent with LiH. X = Cl, H.

(88) The data in Tables 32 and 33 are used in conjunction with the results of other redistribution experiments in co-pending applications to arrive at the final compositions shown in Table 34

(89) TABLE-US-00034 TABLE 34 Final Product Compositions After Reduction, Cleavage and Redistribution SAMPLE A SAMPLE B COMPOUND wt % g/MT wt % g/MT CH.sub.2SiH.sub.3 0.01 103.56 0.03 195.07 (CH.sub.3).sub.2SiH.sub.2 8.69 64147.05 7.87 55750.15 CH.sub.3SiH.sub.2Cl 3.36 24805.64 4.60 32537.87 (CH.sub.3).sub.3SiH 0.00 0 0.00 0 (CH.sub.3).sub.2SiHCl (M2H) 61.79 456374.71 60.75 430182.72 CH.sub.3SiHCl.sub.2 (MH) 0.10 737.63 0.17 1215.78 (CH.sub.3).sub.3SiCl (M) 6.30 46549.75 8.51 60233.16 CH.sub.3SiCl.sub.3 (T) 0.00 0 0.00 0 (CH.sub.3).sub.2SiCl.sub.2 (D) 19.75 145838.12 18.07 127955.50 T/D 0 0 TOTAL MCS WEIGHT, g 738556.45 708070.24 TOTAL LiCl PRODUCED, g 325407 310436

(90) The results of these Examples demonstrate that the use of only 6.7 weight percent LiH can alter the composition of the product from the Rochow-Müller Direct Synthesis from being primarily dimethyldichlorosilane (D) to primarily dimethylchlorosilane (M2H).

(91) Methyltrichlorosilane (T) is consumed and trimethylchlorosilane (M) is increased. The product yield is approximately 71-74%. Volatile hydridosilanes (CH.sub.3SiH.sub.3, (CH.sub.3).sub.2SiH.sub.2 and CH.sub.3SiH.sub.2Cl) can be recovered and added to fresh Rochow-Müller Direct Synthesis product, or reused in redistribution with methylchlorosilanes. Overall, more valuable monomers are obtained. Additionally, LiCl (>300 kg) produced can be recovered and used to produce Li and LiH.

Example 22

On the Recovery of LiCl for Manufacture of Li and LiH

(92) This Example illustrates the recovery, purification and characterization of LiCl produced when LiH was used in the reduction of (CH.sub.3).sub.2SiCl.sub.2 to (CH.sub.3).sub.2SiHCl and (CH.sub.3).sub.2SiH.sub.2 as is described in co-pending applications.

(93) Solid from the reaction was recovered by filtration and treated with diglyme saturated with gaseous HCl to convert any unreacted LiH to LiCl. It was then washed four times with dry pentane and dried in vacuo at 630° C. for one hour.

(94) The LiCl was dissolved in diglyme and C.sub.6D.sub.6 characterized by .sup.7Li-NMR recorded on a Bruker AV-500 spectrometer.

(95) The single resonance observed (6=0.23 ppm) is assignable to the chemical shift of LiCl by comparison with an authentic sample of LiCl (6=0.20 ppm).

(96) The dried LiCl was mixed with KCl in the proportions shown in the Table below. Melting behavior of the samples was recorded by a camera attached to the automated melting point apparatus, OptiMelt MPA 100. For comparison, the melting behavior of authentic LiCl—KCl samples was also measured. Both sets of data are shown in the Table 35.

(97) TABLE-US-00035 TABLE 35 WEIGHT MELTING POINTS, ° C. MELTING POINTS, ° C. RATIOS, RECOVERED AUTHENTIC LiCLKCl LiCLKCl LiCLKCl 40:60 355.3 354.8 50:50 356.1 355.6 60:40 355.9 356.6

(98) The observed melting points for the recovered and control samples are in good agreement with each other. The 40:60 LiCl—KCl sample corresponds to the eutectic composition. The melting point observed is consistent with published values (see S. Zemczuzny, et al., Zeitschrift für Anorganische Chemie, 46 (1910) 403-428). The melting point data prove that the recovered LiCl forms a pure eutectic with KCl and thereby satisfies one of the quality criteria for electrolytic Li recovery.

Example 23

(99) To prove the assumption of Example 21 and to elucidate optimum reaction conditions for the formation of Me.sub.2SiHCl in high yields, the complex crude mixture of the Rochow-Müller Direct Process was simulated by admixing the single compounds in a molar ratio listed in Table 36, with Me.sub.2SiCl.sub.2 as the main component (91.65 mol %), MeSiCl.sub.3 being present in 4.85 mol %.

(100) TABLE-US-00036 TABLE 36 Density M of the of the M .sup.29Si-NMR mixture Chlorine Density mixture Compound [g/mol] integrals Mol % [g/mol] in mixture [g/ml] [g/ml] Me.sub.2SiCl.sub.2 129.06 1 91.646 118.28 1.832928 1.064 0.97511 Me.sub.3SiCl 108.64 0.0216 1.980 2.15 0.019795 0.856 0.01694 MeSiCl.sub.3 149.48 0.0529 4.848 7.25 0.145442 1.273 0.06171 Me.sub.5Si.sub.2Cl 166.8 0.0003 0.027 0.05 0.000274 0.862 0.00023 (ClMe.sub.2Si).sub.2 187.21 0.0003 0.027 0.05 0.000549 1.006 0.00027 (Cl.sub.2MeSi).sub.2 228.04 0.01025 0.939 2.14 0.037575 1.269 0.01192 ClMe.sub.2Si—SiMeCl.sub.2 207.63 0.0055 0.504 1.05 0.015121 1.13 0.00569 Me.sub.3Si—SiMeCl.sub.2 187.21 0.0003 0.027 0.05 0.000549 1.006 0.00027 Total — 1.09115 100 131.01 2.052238 — 1.072

(101) The chlorosilane reductions, the disilane cleavage reaction and Si—H/Si—Cl redistribution with about 1 to about 5 wt-% nBu.sub.4PCl were performed in sealed NMR tubes to prevent evaporation of low boiling components, such as Me.sub.2SiH.sub.2 and MeSiH.sub.3. In case n-Bu.sub.4PCl decomposes running the reactions, n-Bu.sub.3P forms in addition to (poly-) but-1-ene and hydrogen chloride that is responsible for increasing formation of hydrido substituted monosilanes and/or additional chlorination of Si—H bonds (of mono- and disilanes) in to Si—Cl moieties. The products formed upon heating the reaction mixtures and the conversion rates of lithium hydride are given in mol % and are listed in Table 37 for diglyme as solvent.

(102) TABLE-US-00037 TABLE 37.sup.1) Diglyme Conversion 40 mol % of LiH LiH Me.sub.2SiCl.sub.2 Me.sub.3SiCl Me.sub.2SiHCl MeSiHCl.sub.2 MeSiH.sub.2Cl Me.sub.2SiH.sub.2 MeSiH.sub.3 [%] Remarks r.t., 12, 74.1 1.5 9.6 0.7 1.5 5.9 6.7 42 0% Decomposition of 6 h nBu.sub.4PCl 60° C., 52.5 1.6 27.8 — 0.8 8.9 8.4 68 1% Decomposition of 2 h nBu.sub.4PCl 70° C., 41.2 1.3 40.3 — 1.6 8.2 7.4 76 2% Decomposition of 2 h nBu.sub.4PCl 70° C., 37.3 1.9 44.4 1.5 8.2 6.7 79 2% Decomposition of 2 h nBu.sub.4PCl 80° C., 34.1 1.7 48.5 — 2.4 7.2 6.1 80 3% Decomposition of 2 h nBu.sub.4PCl 90° C., 32.0 1.6 52.4 — 1.9 6.4 5.8 81 3% Decomposition of 2 h nBu.sub.4PCl 100° C., 30.3 1.8 53.7 — 1.8 6.7 5.8 83 3% Decomposition of 2 h nBu.sub.4PCl 110° C., 25.9 1.6 54.1 — 2.1 9.8 6.5 91 5% Decomposition of 2 h nBu.sub.4PCl 120° C., 25.3 1.7 55.0 — 2.0 8.8 7.0 92 5% Decomposition of 2 h nBu.sub.4PCl 130° C., 25.2 1.3 54.9 — 2.0 9.3 7.3 93 5% Decomposition of 2 h nBu.sub.4PCl 130° C., 24.0 1.7 54.7 — 1.9 10.1 7.7 95 5% Decomposition of 2 h nBu.sub.4PCl 135° C., 23.5 1.4 54.9 — 1.9 10.3 8.0 96 5% Decomposition of 4 h nBu.sub.4PCl 140° C., 21.7 1.3 54.8 — 1.7 12.1 8.4 100 5% Decomposition of 2 h nBu.sub.4PCl 150° C., 21.8 1.5 54.7 — 1.7 12.2 8.1 100 5% Decomposition of 4 h nBu.sub.4PCl .sup.1)NMR scale reaction to prove the conditions for reduction, cleavage and redistribution reactions. For the reaction 40 mol % LiH (in relation to the total chlorine content present in the silane mixture) was used to convert. The concentration of LiH was 17 mol/L related to the solvent. C.sub.6D.sub.6 (0.2 mL) was added as NMR standard. C.sub.6D.sub.6 is not able to dissolve LiH or LiCl and should not have any affect on the reactions. Reactions were started at room temperature and were controlled increasing temperature form 60° C. in 10° C. steps. .sup.7Li-NMR-shifts of LiCl in Diglyme: 0.56 ppm, in 1,4-dioxane: 1.11 ppm and in THF: 0.87 ppm. between 5 to 10 wt.

(103) Table 38 contains data obtained for comparable reactions, but in the presence of 7 mol % of the crown ether 12-crown-4 in the reaction mixture. In the latter case chlorosilane reduction started only at 80° C., at 100° C. the amount of Me.sub.2SiHCl is >40 mol %, while the molar concentration of Me.sub.2SiH.sub.2 is very low (3.2 mol %). At temperature above 110° C. the strong formation of solids prevents further NMR investigations on the product mixture.

(104) TABLE-US-00038 TABLE 38.sup.1) Diglyme + Conversion 7 vol % of LiH crown Me.sub.2SiCl.sub.2 Me.sub.3SiCl Me.sub.2SiHCl MeSiHCl.sub.2 MeSiH.sub.2Cl Me.sub.2SiH.sub.2 MeSiH.sub.3 [%] Remarks r.t., 12, 92.9 2.8 — — — — — 0 0% Decomposition of 6 h nBu.sub.4PCl 3.8% MeSiCl.sub.3 <1% disilanes 60° C., 92.9 2.8 — — — — — 0 0% Decomposition of 2 h nBu.sub.4PCl 3.8% MeSiCl.sub.3 <1% disilanes 80° C., 84.7 1.7 0.9 — — 5.1 6.8 40 0% Decomposition of 2 h nBu.sub.4PCl 0.9% MeSiCl.sub.3 90° C., 74.1 1.5 16.3 — — 1.5 6.7 49 0% Decomposition of 2 h nBu.sub.4PCl 100° C., 45.2 1.8 41.2 1.8 3.2 3.2 3.6 83 1% Decomposition of 2 h nBu.sub.4PCl 110° C., NMR analysis failed because of too much solids in the NMR tube — 2 h 120° C., NMR analysis failed because of too much solids in the NMR tube — 2 h .sup.1)NMR scale reaction to prove the conditions for reduction, cleavage and redistribution reactions. For the reaction 40 mol % LiH (in relation to the total chlorine content present in the silane mixture) was used to convert. The concentration of LiH was 17 mol/L in relation to the solvent. C.sub.6D.sub.6 (0.2 mL) was added as NMR standard. C.sub.6D.sub.6 is not able to dissolve LiH or LiCl and should not have any affect on the reactions. Reactions were started at room temperature and were controlled increasing temperature form 60° C. in 10° C. steps. .sup.7Li-NMR-shifts of LiCl in Diglyme: 0.56 ppm, in 1,4-dioxane: 1.11 ppm and in THF: 0.87 ppm.

(105) TABLE-US-00039 TABLE 39.sup.1) Conversion 1,4- of LiH dioxane Me.sub.2SiCl.sub.2 Me.sub.3SiCl Me.sub.2SiHCl MeSiHCl.sub.2 MeSiH.sub.2Cl Me.sub.2SiH.sub.2 MeSiH.sub.3 [%] Remarks r.t., 12, 60.6 1.8 21.8 — 0.6 7.9 7.3 63 0% Decomposition of 6 h nBu.sub.4PCl 60° C., 42.0 1.3 42.8 — — 8.4 5.5 79 0% Decomposition of 2 h nBu.sub.4PCl 70° C., 34.6 1.7 49.5 — 1.4 6.6 6.2 87 1% Decomposition of 2 h nBu.sub.4PCl 70° C., 32.3 1.6 53.4 — 0.7 6.5 5.5 88 2% Decomposition of 2 h nBu.sub.4PCl 80° C., 31.2 1.3 54.5 — 0.3 6.5 6.2 90 2% Decomposition of 2 h nBu.sub.4PCl 90° C., 29.4 1.2 55.8 — — 7.1 6.5 93 2% Decomposition of 2 h nBu.sub.4PCl 100° C., 30.0 1.2 55.6 — — 6.9 6.3 92 2% Decomposition of 2 h nBu.sub.4PCl 110° C., 28.9 1.4 55.4 — — 8.1 6.1 93 2% Decomposition of 2 h nBu.sub.4PCl 120° C., 27.9 1.4 55.0 — — 8.1 7.5 97 2% Decomposition of 2 h nBu.sub.4PCl 130° C., 28.7 1.4 55.5 — — 7.2 7.2 95 2% Decomposition of 2 h nBu.sub.4PCl 130° C., 27.7 1.7 54.3 — 1.4 8.0 6.9 97 2% Decomposition of 2 h nBu.sub.4PCl 135° C., 27.8 1.7 55.0 — — 8.0 7.5 97 2% Decomposition of 4 h nBu.sub.4PCl 140° C., 27.9 1.4 54.5 — — 8.4 7.8 98 2% Decomposition of 2 h nBu.sub.4PCl 150° C., 26.7 1.6 53.3 — 2.1 8.3 8.0 100 2% Decomposition of 4 h nBu.sub.4PCl .sup.1)NMR scale reaction to prove the conditions for reduction, cleavage and redistribution reactions. For the reaction 48 mol % LiH (in relation to the total chlorine content present in the silane mixture) was used to convert. The concentration of LiH was 17 mol/L related to the solvent. C.sub.6D.sub.6 (0.2 mL) was added as NMR standard. C.sub.6D.sub.6 is not able to dissolve LiH or LiCl and should not have any affect on the reactions. Reactions were started at room temperature and were controlled increasing temperature form 60° C. in 10° C. steps. .sup.7Li-NMR-shifts of LiCl in Diglyme: 0.56 ppm, in 1,4-dioxane: 1.11 ppm and in THF: 0.87 ppm.

(106) Table 39 covers the results for comparable reactions but in 1,4-dioxane as solvent, Table 40 shows the results obtained with the addition of 7 mol % of 12-crown-4-ether. In this case the observations made were very similar to those results described for the reaction in diglyme with addition of 12-crown-4-ether (Table 38).

(107) TABLE-US-00040 TABLE 40.sup.1) Dioxane + Conversion 7 vol % of LiH crown Me.sub.2SiCl.sub.2 Me.sub.3SiCl Me.sub.2SiHCl MeSiHCl.sub.2 MeSiH.sub.2Cl Me.sub.2SiH.sub.2 MeSiH.sub.3 [%] Remarks r.t., 12, 92.9 2.8 — — — — — 0 0% Decomposition of 6 h nBu.sub.4PCl 3.8% MeSiCl.sub.3 <1% disilanes 60° C., 92.9 2.8 — 0.6 — — — 1 0% Decomposition of 2 h nBu.sub.4PCl 3.2% MeSiCl.sub.3 <1% disilanes 80° C., 75.6 2.3 13.7 — 0.8 1.5 6.0 46 0% Decomposition of 2 h nBu.sub.4PCl 90° C., 60.6 1.8 16.4 — — 14.5 6.7 82 0% Decomposition of 2 h nBu.sub.4PCl 100° C., 40.6 1.7 45.1 — 2.0 5.3 5.3 95 1% Decomposition of 2 h nBu.sub.4PCl 110° C., 35.5 1.4 49.2 — 1.1 7.1 5.7 111 1% Decomposition of 2 h nBu.sub.4PCl 120° C., NMR analysis failed because of too much solids in the NMR tube — 2 h .sup.1)NMR scale reaction to prove the conditions for reduction, cleavage and redistribution reactions. For the reaction 40 mol % LiH (in relation to the total chlorine content present in the silane mixture) was used to convert. The concentration of LiH was 17 mol/L related to the solvent. C.sub.6D.sub.6 (0.2 mL) was added as NMR standard. C.sub.6D.sub.6 is not able to dissolve LiH or LiCl and should not have any affect on the reactions. Reactions were started at room temperature and were controlled increasing temperature form 60° C. in 10° C. steps. .sup.7Li-NMR-shifts of LiCl in Diglyme: 0.56 ppm, in 1,4-dioxane: 1.11 ppm and in THF: 0.87 ppm.

(108) The reactions performed in THF as solvent are listed in Table 41, those runs in the presence of 12-crown-4-ether in Table 42. Reaction performed in THF generally show high LiH conversion rates and formation of the target compound Me.sub.2SiHCl in high yields under moderate reaction conditions.

(109) TABLE-US-00041 TABLE 41.sup.1) Conversion of LiH THF Me.sub.2SiCl.sub.2 Me.sub.3SiCl Me.sub.2SiHCl MeSiHCl.sub.2 MeSiH.sub.2Cl Me.sub.2SiH.sub.2 MeSiH.sub.3 [%] Remarks r.t., 12, 54.9 1.7 23.7 — — 11.5 8.2 61 0% Decomposition of 6 h nBu.sub.4PCl 60° C., 30.6 1.5 48.0 — — 12.3 7.6 81 1% Decomposition of 2 h nBu.sub.4PCl 70° C., 22.4 1.3 55.1 — 1.3 11.6 7.6 88 2% Decomposition of 2 h nBu.sub.4PCl 70° C., 21.2 1.2 57.2 — 1.4 11.9 7.1 89 2% Decomposition of 2 h nBu.sub.4PCl 80° C., 20.8 1.5 56.6 — 1.6 12.0 7.5 90 2% Decomposition of 2 h nBu.sub.4PCl 90° C., 20.4 1.4 56.9 — 1.2 12.4 7.7 90 2% Decomposition of 2 h nBu.sub.4PCl 100° C., 19.9 1.4 57.6 — 0.8 12.9 7.4 91 2% Decomposition of 2 h nBu.sub.4PCl 110° C., 18.7 1.3 57.1 — 1.1 13.9 7.9 93 2% Decomposition of 2 h nBu.sub.4PCl 120° C., 18.2 1.4 56.0 — 1.1 14.6 8.7 95 3% Decomposition of 2 h nBu.sub.4PCl 130° C., 18.4 1.3 56.1 — 1.1 14.8 8.3 95 3% Decomposition of 2 h nBu.sub.4PCl 130° C., 17.4 1.4 55.6 — 0.7 16.5 8.5 97 3% Decomposition of 2 h nBu.sub.4PCl 135° C., 17.0 1.4 56.4 — — 16.6 8.6 97 3% Decomposition of 4 h nBu.sub.4PCl 140° C., 16.7 1.5 56.2 — — 16.5 9.2 99 3% Decomposition of 2 h nBu.sub.4PCl 150° C., 16.4 1.3 54.2 — 1.3 18.2 8.5 100 3% Decomposition of 4 h nBu.sub.4PCl .sup.1)NMR scale reaction to prove the conditions for reduction, cleavage and redistribution reactions. For the reaction 59 mol % LiH (in relation to the total chlorine content present in the silane mixture) was used to convert. The concentration of LiH was 17 mol/L (in relation to the solvent). C.sub.6D.sub.6 (0.2 mL) was added as NMR standard. C.sub.6D.sub.6 is not able to dissolve LiH or LiCl and should not have any affect on the reactions. Reactions were started at room temperature and were controlled increasing temperature form 60° C. in 10° C. steps. .sup.7Li-NMR-shifts of LiCl in Diglyme: 0.56 ppm, in 1,4-dioxane: 1.11 ppm and in THF: 0.87 ppm.

(110) TABLE-US-00042 TABLE 42.sup.1) THF + Conversion 7 vol % of LiH crown Me.sub.2SiCl.sub.2 Me.sub.3SiCl Me.sub.2SiHCl MeSiHCl.sub.2 MeSiH.sub.2Cl Me.sub.2SiH.sub.2 MeSiH.sub.3 [%] Remarks r.t., 12, 92.9 2.8 — — — — — 0 0% Decomposition of 6 h nBu.sub.4PCl 3.8% MeSiCl.sub.3 <1% disilanes 60° C., 92.9 2.8 0.2 1.0 — — — 2 0% Decomposition of 2 h nBu.sub.4PCl 2.6% MeSiCl.sub.3 <1% disilanes 80° C., 75.8 1.5 4.5 — — 11.4 6.8 58 0% Decomposition of 2 h nBu.sub.4PCl 90° C., 54.0 1.6 34.6 0.5 2.7 2.2 4.3 70 1% Decomposition of 2 h nBu.sub.4PCl 100° C., 45.0 1.8 41.0 1.4 3.1 3.2 4.5 83 1% Decomposition of 2 h nBu.sub.4PCl 110° C., 44.0 1.8 43.6 0.4 2.7 2.7 4.8 84 3% Decomposition of 2 h nBu.sub.4PCl 120° C., 43.7 1.7 44.1 — 3.1 3.1 4.4 84 3% Decomposition of 2 h nBu.sub.4PCl 130° C., 38.7 1.6 48.1 — 3.0 3.9 4.7 92 3% Decomposition of 2 h nBu.sub.4PCl 130° C., 39.2 1.6 47.8 — 3.1 3.1 5.1 91 3% Decomposition of 2 h nBu.sub.4PCl 130° C., 38.9 1.6 47.9 — 3.1 3.5 5.1 92 3% Decomposition of 2 h nBu.sub.4PCl 130° C., 37.2 1.5 48.7 — 3.0 4.1 5.6 96 3% Decomposition of 2 h nBu.sub.4PCl 135° C., 36.2 1.5 49.0 — 2.9 4.3 6.0 99 3% Decomposition of 4 h nBu.sub.4PCl 140° C., 35.0 1.4 50.7 — 1.7 4.9 6.3 100 3% Decomposition of 2 h nBu.sub.4PCl 150° C., 34.6 1.7 50.5 — 2.8 5.2 5.2 100 3% Decomposition of 4 h nBu.sub.4PCl .sup.1)NMR scale reaction to prove the conditions for reduction, cleavage and redistribution reactions. For the reaction 41 mol % LiH (in relation to the total chlorine content present in the silane mixture) was used to convert. The concentration of LiH was 17 mol/L (in relation to the solvent). C.sub.6D.sub.6 (0.2 mL) was added as NMR standard. C.sub.6D.sub.6 is not able to dissolve LiH or LiCl and should not have any affect on the reactions. Reactions were started at room temperature and were controlled increasing temperature form 60° C. in 10° C. steps. .sup.7Li-NMR-shifts of LiCl in Diglyme: 0.56 ppm, in 1,4-dioxane: 1.11 ppm and in THF: 0.87 ppm

Example 24

(111) Based on the experiments of Example 23 that were performed with about 1 to about 5 wt-% nBu.sub.4PCl in sealed NMR tubes in only small amounts of reactants, similar experiments were run in sealed reaction ampules with varying gram-amounts of chlorosilanes, molar composition is given in Table 36. In a detailed study different reaction conditions were investigated that are listed under “Remarks” in the Tables.

(112) Table 43 covers the results obtained for reactions in different glymes as solvent: The reaction temperatures were between 110° C. and 150° C. for 60-65 h. The LiH conversion rates were 60-90 mol %, the lower the LiH concentration (in mol/L) the higher were the conversion rates. Obtained yields for Me.sub.2SiHCl were 30-55 mol %, if the amount of Me.sub.2SiH.sub.2 (<30 mol %) is added, the yield of Me.sub.2SiHCl is nearly quantitatively including post processing reactions such as reactions with the ether/HCl reagent (patent pending), or redistribution with Me.sub.2SiCl.sub.2. Remarkably quite strong decomposition of n-Bu.sub.4PCl to give n-Bu.sub.3P besides other phosphine compounds and but-1-ene is observed in some cases, the in situ formed HCl acting as chlorination reagent to retransfer Si—H bonds into Si—Cl.

(113) TABLE-US-00043 TABLE 43 Weight Exchange LiH— Conversion of MCS of H/Cl concentration of LiH [%] [g] [mol %] [mol/L] M2 M3 M2H MH MH2 M2H2 MH3 (±3%) Remarks 13.8 51 16.9 50.5 2.0 37.0 2.0 4.0 2.0 3.0 60 Solvent: Diglyme, 110° C., 65 h 4% Decomposition of nBu.sub.4PCl Corresponds to 30 mol % LiH 9.8 48 10.6 48.3 1.9 38.2 1.9 3.9 1.9 3.9 66 Solvent: Diglyme, 110° C., 65 h 3% Decomposition of nBu.sub.4PCl Corresponds to 31 mol % LiH 10.9 48 10.6 46.3 1.9 40.7 1.9 3.2 2.3 3.7 67 Solvent: Triglyme, 110° C., 65 h 3% Decomposition of nBu.sub.4PCl Corresponds to 31 mol % LiH 9.4 48 10.6 48.3 1.9 40.1 1.0 2.9 1.9 3.9 65 Solvent: Tetraglyme, 110° C., 65 h 0% Decomposition of nBu.sub.4PCl Corresponds to 31 mol % LiH 5.0 81 25.7 28.5 2.0 54.70 — 1.1 9.7 4.0 56 Solvent: Diglyme 110° C., 4 h; 130° C., 65 h 44% Decomposition of nBu.sub.4PCl Corresponds to 44 mol % LiH 4.8 81 5.0 20.0 1.8 56.4 — 1.0 16.0 4.8 65 Solvent: Diglyme 110° C., 4 h; 130° C., 65 h 26% Decomposition of nBu.sub.4PCl Corresponds to 52 mol % LiH 4.0 81 2.0 9.3 1.3 53.1 — — 28.3 8.0 83 Solvent: Diglyme 110° C., 4 h; 130° C., 65 h 0% Decomposition of nBu.sub.4PCl Corresponds to 64 mol % LiH 7.5 43 10.0 59.2 1.8 30.2 2.4 3.5 1.1 1.8 57 Solvent: Diglyme, 130° C., 60 h 5% Decomposition of nBu.sub.4PCl Corresponds to 24 mol % LiH 5.7 65 10.0 40.5 1.6 46.6 0.8 1.6 4.9 4.0 56 Solvent: Diglyme, 130° C., 60 h 30% Decomposition of nBu.sub.4PCl Corresponds to 35 mol % LiH 5.3 86 10.0 25.6 2.3 39.3 — 1.0 24.4 7.4 65 Solvent: Diglyme, 130° C., 60 h 30% Decomposition of nBu.sub.4PCl Corresponds to 54 mol % LiH 3.8 118 25.0 22.4 1.6 43.3 — 0.2 28.9 3.6 49 Solvent: Diglyme, 150° C., 60 h 100% Decomposition of nBu.sub.4PCl Corresponds to 56 mol % LiH 6.1 47 1.25 34.5 2.0 48.3 — 3.8 4.8 6.4 89 Solvent: Diglyme, 130° C., 62 h 0% Decomposition of nBu.sub.4PCl Corresponds to 42 mol % LiH 6.8 39 1.25 47.6 1.9 38.1 1.4 3.8 2.4 4.7 84 Solvent: Diglyme, 120° C., 62 h 0% Decomposition of nBu.sub.4PCl Corresponds to 33 mol % LiH 5.0 48 1.25 35.1 1.8 47.7 — 2.8 6.0 6.6 89 Solvent: Diglyme, 120° C., 62 h 0% Decomposition of nBu.sub.4PCl Corresponds to 43 mol % LiH 8.5 30 1.25 56.2 1.7 31.5 2.2 3.9 1.1 3.4 88 Solvent: Diglyme, 120° C., 62 h 0% Decomposition of nBu.sub.4PCl Corresponds to 27 mol % LiH 4.9 51 17 35.2 2.1 47.9 1.4 2.8 3.9 6.7 80 Solvent: Diglyme 12-crown-4 10vol %, 130° C., 65 h 0% Decomposition of nBu.sub.4PCl Corresponds to 41 mol % LiH 5.4 51 17 47.2 1.9 38.7 1.9 3.8 1.9 4.7 64 Solvent: Diglyme Addition of KCl, 130° C., 65 h 0% Decomposition of nBu.sub.4PCl Corresponds to 33 mol % LiH M2 = Me.sub.2SiCl.sub.2, M3 = Me.sub.3SiCl, M2H = Me.sub.2SiHCl, MH = MeSiHCl.sub.2, MH2 = MeSiH.sub.2Cl, M2H2 = Me.sub.2SiH.sub.2 and MH3 = MeSiH.sub.3

(114) More efficient are comparable reactions in THF as solvent (Table 44), giving high LiH conversion rates for e.g. with 17 molar LiH-concentrations—eventually in the presence of crown-ether—they reach 100 mol %. In this case the yield of Me.sub.2SiHCl is ˜56 mol %, Me.sub.2SiH.sub.2 is formed in ˜17 mol %: Including post processing of the dihydridosilanes the overall yield of Me.sub.2SiHCl will be about 90 mol %. In the presence of crown-ether a solid residue is formed with LiCl adduct formation that can be split again thermally at ˜100° C. into the starting materials and thus will be recycled quantitatively (G. Shore et al., Inorg. Chem. 1999, 38, 4554-4558). In a similar way 1,4-dioxane forms with LiCl a thermo-labile complex that will be split into the adduct forming components at higher temperatures (S. Yamashita et al., Mass Spectroscopy, 11, 106 (1963); 28, 211-216 (1965)). These two findings explain strong solid formation using 1,4-dioxane as solvent, especially in the presence of crown-ethers. That might facilitate product separation because hydridochlorosilanes might be separated from “solid” solvent and/or crown-ether easily with subsequent recycling of the ethers at ˜100° C.

(115) TABLE-US-00044 TABLE 44 Weight Exchange LiH— Conversion of MCS of H/Cl concentration of LiH [%] [g] [mol %] [mol/L] M2 M3 M2H MH MH2 M2H2 MH3 (±3%) Remarks 4.7 51 17 35.5 2.0 50.8 0.7 2.0 8.8 3.2 82 Solvent: THF, 130° C., 65 h 36% Decomposition of nBu.sub.4PCl Corresponds to 42 mol % LiH 4.1 51 17 46.3 1.9 41.6 1.9 2.3 2.3 3.7 63 Solvent: DME, 130° C., 65 h 26% Decomposition of nBu.sub.4PCl Corresponds to 32 mol % LiH 7.6 53 17 24.9 2.1 45.6 0.0 1.0 21.6 4.81 101 Solvent: THF 12-crown-4 5 vol %, 130° C., 65 h 10% Decomposition of nBu.sub.4PCl 18.4 1.8 56.1 — 1.1 17.1 5.5 103 After condensation of all volatile compounds (work up) 8.8 51 17 46.7 1.9 41.1 1.0 2.3 2.3 4.7 64 Solvent: DME 12-crown-4 5 vol %, 130° C., 65 h 10% Decomposition of nBu.sub.4PCl Corresponds to 33 mol % LiH 12.0 51 17 46.5 1.9 39.5 1.9 3.7 2.8 3.7 64 Solvent: Dioxane, 130° C., 65 h 7% Decomposition of nBu.sub.4PCl Corresponds to 33 mol % LiH 48.3 1.9 40.6 1.9 3.4 1.9 2.9 60 After condensation of all volatile compounds (work up) 13.7 51 17 41.7 1.7 43.3 0.8 3.3 3.8 3.4 73 Solvent: Dioxane 12-crown-4 2 vol %, 130° C., 65 h 6% Decomposition of nBu.sub.4PCl Corresponds to 73 mol % LiH 12.1 51 10 41.2 1.6 43.6 0.8 2.9 5.8 4.1 73 Solvent: THF 130° C., 65 h 76% Decomposition of nBu.sub.4PCl Corresponds to 37 mol % LiH 16.8 39 11 55.2 1.7 33.2 2.2 3.8 1.2 2.9 69 Solvent: Dioxane (1:1 in mol dioxane:LiH), 130° C., 64 h 5% Decomposition of nBu.sub.4PCl Corresponds to 27 mol % LiH 17.9 39 14 53.9 1.7 33.6 2.2 3.2 2.2 3.2 72 Solvent: Dioxane/THF (1:1), 130° C., 64 h 2% Decomposition of nBu.sub.4PCl Corresponds to 28 mol % LiH 12.2 39 14 50.8 2.0 35.6 2.0 4.0 2.0 3.6 78 Solvent: Dioxane/THF (1:1), 12-crown-4 3 vol %, 130° C., 64 h 2% Decomposition of nBu.sub.4PCl Corresponds to 28 mol % LiH 4.6 51 17 Solvent: DMF, 130° C., 65 h; Reaction with DMF gives 90% of non-identified compounds 8.8 51 17 Solvent: DMF, 12-crown-4 5 vol %, 130° C., 65 h; Reaction with DMF gives 90% of non-identified compounds M2 = Me.sub.2SiCl.sub.2, M3 = Me.sub.3SiCl, M2H = Me.sub.2SiHCl, MH = MeSiHCl.sub.2, MH2 = MeSiH.sub.2Cl, M2H2 = Me.sub.2SiH.sub.2 and MH3 = MeSiH.sub.3

(116) As can be seen in Table 44, dimethoxyethane (DME) can be used as solvent too, but shows no significant efforts compared to the other ethers used in our investigations. The same is true for mixtures of ethers as exemplarily shown for reactions performed in 1/1 mixtures of 1,4-dioxane and THF.