PROCESS FOR SYNTHESIZING ALKOXY GROUP-CONTAINING AMINOSILOXANES

Abstract

Processes for preparing aminosiloxanes. The process includes providing an alkoxy-rich partial hydrolyzate of silanes and silane mixtures and reacting the alkoxy-rich partial hydrolyzate of silanes and silane mixtures with one or more aminosilanes in the presence of a basic catalyst

Claims

1-14. (canceled)

15. A process for preparing aminosiloxanes, comprising: providing an alkoxy-rich partial hydrolyzate of silanes and silane mixtures independently selected from the general formulae I, Ia, Ib and II
[R.sup.1.sub.3Si(OR.sup.2)]  (Ia),
[R.sup.1.sub.2Si(OR.sup.2).sub.2]  (Ib),
[Si(OR.sup.2).sub.4]  (I) and
[R.sup.1Si(OR.sup.2).sub.3]  (II); reacting the alkoxy-rich partial hydrolyzate of silanes and silane mixtures with one or more aminosilanes independently selected from the general formulae IIIa to Va or a partial hydrolyzate thereof
[R.sup.3aSi(OR.sup.4).sub.3]  (IIIa),
[R.sup.3a.sub.2Si(OR.sup.4).sub.2]  (IVa) and
[R.sup.3a.sub.3Si(OR.sup.4)]  (Va) in the presence of a basic catalyst; wherein R.sup.1 is a monovalent C.sub.1-C.sub.20-hydrocarbon radical which is unsubstituted or substituted by halogen atoms; wherein R.sup.2 and R.sup.4 may be the same or different and are a hydrogen atom or C.sub.1-C.sub.20-hydrocarbon radical which is unsubstituted or substituted by halogen atoms; and wherein R.sup.3a is a monovalent C.sub.1-C.sub.20-hydrocarbon radical comprising one or more basic nitrogen atoms, or a monovalent C.sub.1-C.sub.20-hydrocarbon radical which is unsubstituted or substituted by halogen atoms.

16. The process of claim 15, wherein the radical R.sup.1 is selected from methyl radical and phenyl radical.

17. The process of claim 15, wherein the radical R.sup.2 is selected from methyl radical and ethyl radical.

18. The process of claim 15, wherein the alkoxy-rich partial hydrolyzate is prepared from at least 70% by weight silane of the general formula II.

19. The process of claim 15, wherein the alkoxy-rich partial hydrolyzate has an average molar mass M.sub.n according to GPC from 100 to 2000 g/mol.

20. The process of claim 15, wherein 10 to 200 parts by weight of aminosilane are used per 100 parts by weight of partial hydrolyzate.

21. The process of claim 15, wherein the basic catalyst is selected from alkali metal hydroxides and alkaline earth metal hydroxides, alkali metal alkoxides and alkaline earth metal alkoxides and alkali metal siloxanolates and alkaline earth metal siloxanolates.

22. The process of claim 15, wherein the basic catalyst is selected from sodium methoxide, sodium ethoxide, potassium hydroxide, potassium methoxide and potassium ethoxide.

23. The process of claim 15, wherein an acid is used at the end of the reaction to deactivate the basic catalyst.

24. The process of claim 23, wherein an acid is used, the salt of which is soluble in the aminosiloxanes produced at 20° C.

25. The process of claim 15, wherein the reaction is carried out for so long that the composition no longer changes under the reaction conditions.

26. A process for preparing aminosiloxanes, comprising: providing an alkoxy-rich partial hydrolyzate of silanes independently selected from the general formulae I and II
[Si(OR.sup.2).sub.4]  (I) and
[R.sup.1Si(OR.sup.2).sub.3]  (II); reacting the alkoxy-rich partial hydrolyzate of silanes with one or more aminosilanes independently selected from the general formulae III to V
[R.sup.3Si(OR.sup.4).sub.3]  (III),
[R.sup.3.sub.2Si(OR.sup.4).sub.2]  (IV) and
[R.sup.3.sub.3Si(OR.sup.4)]  (V) in the presence of the basic catalyst; wherein R.sup.1 is a monovalent C.sub.1-C.sub.20-hydrocarbon radical which is unsubstituted or substituted by halogen atoms; wherein R.sup.2 and R.sup.4 may be the same or different and are a hydrogen atom or C.sub.1-C.sub.20-hydrocarbon radical which is unsubstituted or substituted by halogen atoms; and wherein R.sup.3 is a monovalent C.sub.1-C.sub.20-hydrocarbon radical comprising one or more basic nitrogen atoms.

27. The process of claim 26, wherein the radical R.sup.2 is selected from methyl radical and ethyl radical.

28. The process of claim 26, wherein the radical R.sup.3 is a radical of the general formula VI
—R.sup.5—[NR.sup.6—R.sup.7—].sub.gNR.sup.8.sub.2  (VI); where R.sup.5 is a divalent linear or branched hydrocarbon radical having 1 to 18 carbon atoms; wherein R.sup.6 and R.sup.8 have the definition of R.sup.1 and hydrogen; and wherein R.sup.7 is a divalent hydrocarbon radical having 1 to 6 carbon atoms and g is 0, 1, 2, 3 or 4.

29. The process of claim 26, wherein the radical R.sup.3 is selected from H.sub.2N(CH.sub.2).sub.3— and H.sub.2N(CH.sub.2).sub.2NH(CH.sub.2).sub.3—.

30. The process of claim 26, wherein the alkoxy-rich partial hydrolyzate is prepared from at least 70% by weight silane of the general formula II; or wherein the alkoxy-rich partial hydrolyzate has an average molar mass M.sub.n according to GPC from 100 to 2000 g/mol.

31. The process of claim 26, wherein 10 to 200 parts by weight of aminosilane are used per 100 parts by weight of partial hydrolyzate.

32. The process of claim 26, wherein the basic catalyst is selected from alkali metal hydroxides and alkaline earth metal hydroxides, alkali metal alkoxides and alkaline earth metal alkoxides and alkali metal siloxanolates and alkaline earth metal siloxanolates.

33. The process of claim 26, wherein the basic catalyst is selected from sodium methoxide, sodium ethoxide, potassium hydroxide, potassium methoxide and potassium ethoxide.

34. The process of claim 26, wherein an acid is used at the end of the reaction to deactivate the basic catalyst; or wherein the reaction is carried out for so long that the composition no longer changes under the reaction conditions.

Description

EXAMPLES

[0092] In the following examples, unless otherwise stated in each case, all amounts and percentages are based on weight, all pressures are 0.10 MPa (abs.) and all temperatures are 20° C.

[0093] 1. Reactants and Measurement Methods:

[0094] 1.1 Alkoxysilanes

[0095] a) GENIOSIL® GF 93: 3-aminopropyltriethoxysilane (CAS: 919-30-2) from Wacker Chemie AG, with a purity of at least 97% (AS1).

[0096] b) GENIOSIL® GF 96: 3-aminopropyltrimethoxysilane (CAS: 13822-56-5) from Wacker Chemie AG, with a purity of at least 95% (AS2).

[0097] c) SILANE M1-TRIETHOXY: methyltriethoxysilane (CAS: 2031-67-6) from Wacker Chemie AG, with a purity of at least 97%.

[0098] d) SILANE M1-TRIMETHOXY: trimethoxymethylsilane (CAS: 1185-55-3) from Wacker Chemie AG, with a purity of at least 97%.

[0099] e) SILANE P-TRIETHOXY: triethoxyphenylsilane (CAS: 780-69-8) from Wacker Chemie AG, with a purity of at least 98%.

[0100] f) SILRES® MSE 100: methoxy-functional methylpolysiloxane resin from Wacker Chemie AG, having a viscosity of 20-35 mm.sup.2/s.

[0101] 1.2 Other Chemicals

[0102] Trimethoxyphenylsilane (CAS: 2996-92-1), concentrated hydrochloric acid (acid 1), isotridecyl phosphate (acid 2), 2-butyloctanoic acid (acid 3), methanol (HPLC grade), ethanol (HPLC grade), sodium methoxide, sodium ethoxide, potassium ethoxide and potassium hydroxide were sourced from common suppliers. The solutions of the alkali metal alkoxides and of potassium hydroxide used in the examples were produced starting from the solids using the pure alcohols mentioned above.

[0103] 1.3 Viscosity:

[0104] The measurement of the viscosities of the materials in the context of the present invention was carried out with temperature control at

[0105] 25° C. using a Stabinger rotational viscometer SVM3000 from Anton Paar at 25° C. (standard).

[0106] 1.4 Gel Permeation Chromatography:

[0107] The mass-average molar mass M.sub.w and also the number-average molar mass M.sub.n are determined by size exclusion chromatography (SEC) against polydimethylsiloxane standards, in toluene, at 35° C., flow rate 0.7 ml/min and detection by RI (refractive index detector) on a MesoPore-OligoPore column set (Agilent, Germany) with an injection volume of 10 μl.

[0108] 1.5 NMR Spectroscopy (.sup.29Si- and .sup.1H-NMR)

[0109] 1.5.1 Average Empirical Formula:

[0110] The average composition of the partial hydrolysates according to section 2 was determined by .sup.1H nuclear magnetic resonance spectroscopy (.sup.1H-NMR; Bruker Avance III HD 500 (.sup.1H: 500.2 MHz) spectrometer with BBO 500 MHz S2 probe head; 50 mg of the relevant sample in 500 μl of CD.sub.2Cl.sub.2). Here, the signal intensities of the Ph, Me, MeO or EtO functionalities are determined and, after normalization to the respective proton number of the individual groups, compared to one another.

[0111] 1.5.2 Evaluation of the Equilibration State:

[0112] The equilibration state of the aminosiloxanes from Examples 1-15 was determined using .sup.29Si nuclear magnetic resonance spectroscopy (.sup.29Si-NMR; Bruker Avance III HD 500 (.sup.29Si: 99.4 MHz) spectrometer with BBO 500 MHz S2 probe head; inverse gated pulse sequence (NS=3000); 150 mg of the relevant sample in 500 μl of CD.sub.2Cl.sub.2). The intensity ratio between the amino-functionalized monomer introduced and the methyl- or phenyl-functionalized trialkoxysilanes formed during the equilibration reaction is specified. For mixed methoxy/ethoxy systems, i.e. systems in which an ethoxysilane is equilibrated with a methoxysilane, the alkoxy group exchange that occurs during the equilibration reaction must be taken into account. Consequently, the ratio of the sum of the respective related individual components (i.e. resulting from the transalkoxylation) is determined. Using the example of the equilibration of methyltrimethoxysilane with 3-aminopropyltriethoxysilane, the signal intensities of H.sub.2N(CH.sub.2).sub.3Si(OEt).sub.3, H.sub.2N(CH.sub.2).sub.3Si(OEt).sub.2(OMe), H.sub.2N(CH.sub.2).sub.3Si(OEt)(OMe).sub.2, H.sub.2N(CH.sub.2).sub.3Si(OMe).sub.3 would be summed up and would be divided by the sum of the signal intensities of the individual components MeSi(OMe).sub.3, MeSi(OMe).sub.2(OEt), MeSi(OMe)(OEt).sub.2 and MeSi(OEt).sub.3. The value thus obtained is subtracted from 1. The result is stated in %.

[0113] To be able to clearly identify the mixed methoxy/ethoxy compounds by .sup.29Si-NMR, two reference experiments were carried out in advance.

[0114] 1.5.3 Identification of Me(OEt).sub.2(OMe)Si and Me(OEt)(OMe).sub.2Si

[0115] In the first experiment, equimolar amounts of methyltriethoxysilane and methyltrimethoxysilane were mixed. 300 ppm by weight of a sodium methoxide solution (30% by weight in methanol) was added and the mixture was heated to 60° C. for one hour. 100 mg of this mixture were mixed with 900 mg of the partial hydrolyzate from Example 2 and a .sup.29Si NMR spectrum of a sample of this mixture was recorded in CD.sub.2Cl.sub.2.

[0116] 1.5.4 Identification of RSi(OEt).sub.2(OMe)Si and RSi(OEt)(OMe).sub.2Si

[0117] In further separate experiments, equimolar amounts of the related aminotriethoxysilanes and aminotrimethoxysilanes (where R═H.sub.2N(CH.sub.2).sub.3— and H.sub.2N(CH.sub.2).sub.2NH(CH.sub.2).sub.3—) were mixed. 300 ppm by weight of a sodium methoxide solution (30% by weight in methanol) was added and the mixture was heated at 60° C. for one hour. 100 mg of this mixture were mixed with 900 mg of the partial hydrolyzate from Example 2 and a .sup.29Si NMR spectrum of a sample of this mixture was recorded in CD.sub.2Cl.sub.2.

[0118] 2. Preparation of Partial Hydrolyzates—Resins A1-A4

[0119] 2.1 Partial Hydrolyzate of Methyltriethoxysilane (Resin A1)

[0120] 2238 g of methyltriethoxysilane are initially charged in a 4 L three-necked flask equipped with a KPG stirrer and a 500 mL pressure-equalizing dropping funnel. With intensive stirring, 266.8 g of deionized water are added dropwise over a period of one hour via the dropping funnel. The mixture is then stirred at room temperature for one hour. The adhering ethanol is removed by distillation at 40° C. and 145 mbar in a rotary evaporator. After filtration through a fluted filter, a clear, colorless fluid is obtained. According to .sup.1H and .sup.29Si-NMR spectra in CD.sub.2Cl.sub.2, this product is a mixture of methyltriethoxysilane and other (ethoxy-functionalized) methylsiloxanes having an average composition of MeSi(OEt).sub.0.64, a viscosity of 33.2 mPa*s, a density of 1.090 g/L and a polydispersity of 2.43 (M.sub.n: 1024 g/mol, M.sub.w: 2492 g/mol). The material obtained is hereinafter referred to as resin A1.

[0121] 2.2. Partial Hydrolyzate of Methyltrimethoxysilane (Resin A2)

[0122] SILRES® MSE 100 from Wacker Chemie AG is used as partial hydrolyzate of methyltrimethoxysilane. The material used had a viscosity of 38.7 mPa*s and an average composition of MeSi(OMe).sub.0.84. The material is hereinafter referred to as resin A2.

[0123] 2.3 Partial Hydrolyzate of Triethoxyphenylsilane (Resin A3)

[0124] 1000 g of triethoxyphenylsilane are initially charged in a 2 L three-necked flask equipped with a KPG stirrer and a 500 mL pressure-equalizing dropping funnel. A mixture consisting of 86.1 g of deionized water and 10.1 g of concentrated hydrochloric acid is added dropwise via the dropping funnel over a period of 30 minutes with intensive stirring. The mixture is then stirred at room temperature for two hours. The adhering ethanol is removed by distillation at 60° C. and 70 mbar in a rotary evaporator. A clear, colorless fluid is obtained. According to .sup.1H and .sup.29Si-NMR spectra, this product is a mixture of ethoxy-functionalized phenylsiloxanes having an average composition of PhSi(OEt).sub.0.58, a viscosity of 1800 mPa*s and a polydispersity of 2.68 (M.sub.n: 305 g/mol, M.sub.w: 815 g/mol). The material obtained is hereinafter referred to as resin A3.

[0125] 2.4 Partial Hydrolyzate of Trimethoxyphenylsilane (Resin A4)

[0126] 1000 g of trimethoxyphenylsilane are initially charged in a 2 L three-necked flask equipped with a KPG stirrer and a 500 mL pressure-equalizing dropping funnel. A mixture consisting of 92.6 g of deionized water and 4.0 g of concentrated hydrochloric acid is added dropwise via the dropping funnel over a period of 30 minutes with intensive stirring. The mixture is then stirred at room temperature for two hours. The adhering methanol is removed by distillation at 40° C. and 100 mbar in a rotary evaporator. A clear, colorless fluid is obtained. According to .sup.1H and .sup.29Si-NMR spectra in CD.sub.2Cl.sub.2, this product is a mixture of methoxy-functionalized phenylsiloxanes having an average composition of PhSi(OMe).sub.0.97, a viscosity of 377 mPa*s and a polydispersity of 2.00 (M.sub.n: 277 g/mol, M.sub.w: 555 g/mol). The material obtained is hereinafter referred to as resin A4.

[0127] 3. Preparation of Aminosiloxanes by Equilibration of Partial Hydrolyzates—General Synthesis Procedure:

[0128] In a 1 L or 2 L three-necked flask equipped with a KPG stirrer, a reflux condenser with bubble counter and an olive with an argon connection, the resin and the aminosilane specified in the respective example are first mixed according to the weights in Table 1. The reaction apparatus is then inertized with argon. The catalyst solution (according to the weights in Table 1; ppm by weight are based on the total mass of resin and aminosilane (AS)) is added in the countercurrent of argon. Depending on the example, the material is equilibrated at a specified temperature (see Table 1). The catalyst is neutralized by adding the acid specified in Table 1. When using concentrated hydrochloric acid, equimolar amounts of substance are added to the catalyst. If acids 2 or 3 are used, three times the amount of acid—based on the equimolar amount of substance to the catalyst used—is added in each case. The solid precipitating when using concentrated hydrochloric acid (acid 1) is isolated by filtration through a fluted filter using an argon bell jar. When acids 2 or 3 were used, no precipitation was observed and consequently no filtration was carried out. The weights and synthesis conditions of the examples are shown in Table 1. The analytical data for the products obtained are presented in Table 2.

TABLE-US-00001 TABLE 1 Summary of the reactants, catalysts, neutralizing agents, synthesis conditions and weights used in the examples. The synthesis was carried out according to the general synthesis procedure in section 3. Catalyst Internal used; weight temperature [° C.]; Acid Resin used; Aminosilane [ppm by equilibration time used for Yield Examples weight [g] used; weight [g] weight*] [hours] neutral. [%] Example 1 Resin A1; 500 Silane AS1; 500 NaOMe; 400 100; 2 Acid 1 98.7 Example 2 Resin A1; 1025 Silane AS1; 475 NaOMe; 400 100; 2 Acid 1 99.1 Example 3 Resin A1; 1025 Silane AS1; 438 NaOMe; 400 100; 2 Acid 1 99.0 Example 4 Resin A1; 410 Silane AS1; 160 NaOMe; 400 100; 2 Acid 1 98.0 Example 5 Resin A1; 410 Silane AS1; 146 NaOMe; 400 100; 2 Acid 1 98.6 Example 6 Resin A1; 1025 Silane AS1; 438 NaOMe; 400  50; 5 Acid 1 98.9 Example 7 Resin A1; 1025 Silane AS1; 438 NaOMe; 400  25; 18 Acid 1 98.8 Example 8 Resin A1; 550 Silane AS1; 225 NaOMe; 400 100; 2 Acid 2 100 Example 9 Resin A1; 550 Silane AS1; 225 NaOMe; 400 100; 2 Acid 3 100 Example 10 Resin A1; 550 Silane AS1; 225 NaOEt; 700 100; 2 Acid 1 98.8 Example 11 Resin A1; 550 Silane AS1; 225 KOEt; 780 100; 2 Acid 2 100 Example 12 Resin A1; 550 Silane AS1; 225 KOH; 650 100; 2 Acid 2 100 Example 13 Resin A2; 1000 Silane AS1; 500 NaOMe; 400 100; 2 Acid 1 99.1 Example 14 Resin A3; 240 Silane AS1; 103 NaOMe; 400 100; 2 Acid 1 98.6 Example 15 Resin A4; 342 Silane AS1; 146 NaOMe; 400 100; 2 Acid 1 98.9 Example 16 Resin A2; 50 Silane AS2; 50 NaOMe; 400 100; 2 Acid 2 100 Example 17 Resin A2; 50 Silane AS2; 25 NaOMe; 400 100; 2 Acid 2 100 *The ppm by weight figure refers to the weight of catalyst solution (30% by weight in methanol for NaOMe, 29% by weight in methanol for KOH, 21% by weight in ethanol for NaOEt and 24% by weight in ethanol for KOEt) based on the total mass of resin and aminosilane. The catalyst solutions were produced from the solids. The solids were weighed out in a glove box.

TABLE-US-00002 TABLE 2 Summary of the analytical results of the examples given in Table 1. GPC Equilibration state Viscosity M.sub.n M.sub.w Polydis- according to 1.5.2 Examples [mPa*s] [g/mol] [g/mol] persity [%] Example 1 6.9 171 251 1.47 64.1 Example 2 18.9 328 386 1.18 86.0 Example 3 23.2 290 403 1.39 87.5 Example 4 29.7 295 422 1.43 88.5 Example 5 38.0 300 447 1.49 90.6 Example 6 23.0 290 403 1.39 88.7 Example 7 23.1 291 405 1.39 89.5 Example 8 38.4 270 365 1.32 87.4 Example 9 34.1 299 415 1.39 85.8 Example 10 35.4 323 465 1.44 88.0 Example 11 36.9 309 444 1.44 85.5 Example 12 35.7 285 382 1.34 87.4 Example 13 14.1 281 354 1.26 87.9 Example 14 79.0 568 1243 2.19 60.3 Example 15 42.0 374 611 1.63 94.0 Example 16 6.3 64 128 1.99 54.9 Example 17 17.1 118 270 2.29 82.4

[0129] The aminosiloxanes are in the viscosity range of 5-100 mPa*s.

[0130] Since the reaction consists only of an equilibration, the total content of alkoxy groups remains the same. A practical consequence is the fact that the methyltrialkoxysilane is also released from the partial hydrolyzate during equilibration. If there were no preferred incorporation of amino groups, the equilibration state would have to be 0%; equimolar parts of methyltrialkoxysilane and aminotrialkoxysilane would then be present. However, since the measured values are typically >85% (with the exception of the examples where larger amounts of aminosilane are used), this quantity demonstrates that the aminosilane is preferentially incorporated during equilibration, which is also surprising here.