Method for the preparation of thiocarbonates
11247979 · 2022-02-15
Assignee
Inventors
- Peter Rudolf (Ludwigshafen, DE)
- Indre Thiel (Ludwigshafen, DE)
- Markus Jegelka (Ludwigshafen, DE)
- Jan-Dirk Arndt (Ludwigshafen, DE)
- Joaquim Henrique Teles (Ludwigshafen, DE)
Cpc classification
C07D411/12
CHEMISTRY; METALLURGY
International classification
Abstract
Process for the preparation of a compound with at least one five-membered cyclic monothiocarbonate group wherein a) a compound with at least one epoxy group is used as starting material b) the compound is reacted with phosgene or an alkyl chloroformate thus giving an adduct and c) the adduct is reacted with a compound comprising anionic sulfurthus obtaining the compound with at least one five-membered cyclic monothiocarbonate group.
Claims
1. A process for the preparation of a compound with at least one five-membered cyclic monothiocarbonate group, comprising: a) employing a compound with at least one epoxy group as a starting material; b) reacting the compound with at least one epoxy group with phosgene or an alkyl chloroformate to obtain an adduct; and c) reacting the adduct with a compound comprising anionic sulfur to obtain the compound with at least one five-membered cyclic monothiocarbonate group.
2. The process according to claim 1, wherein a) an epoxy compound of formula Ia ##STR00049## with R.sup.1a to R.sup.4a independently from each other representing hydrogen or an organic group with up to 50 carbon atoms whereby, alternatively, R.sup.2a, R.sup.4a and the two carbon atoms of the epoxy group may also together form a five to ten membered carbon ring is used as the starting material, b) the compound of formula Ia is reacted with a compound of formula II ##STR00050## wherein X is Cl or a group O—R.sup.5 with R.sup.5 representing a C1-to C4 alkyl group to obtain an adduct of formula IIIa ##STR00051## wherein R.sup.1a to R.sup.4a have the meaning above; and c) the adduct of formula IIIa is reacted with a compound comprising anionic sulfur to obtain the monothiocarbonate of formula IVa ##STR00052## wherein R.sup.1a to R.sup.4a have the meaning above.
3. The process according to claim 2, wherein at least one of R.sup.1a to R.sup.4a in formula Ia is not hydrogen.
4. The process according to claim 2, wherein two or three of R.sup.1a to W.sup.4a in formula Ia represent hydrogen and the other R.sup.1a to R.sup.4a represent an organic group.
5. The process according to claim 4, wherein the R.sup.1a to R.sup.4a not being hydrogen represent a group CH.sub.2—O—R.sup.6 or CH.sub.2—O—C(═O)—R.sup.7 with R.sup.6 and R.sup.7 being an organic group with at maximum 30 carbon atoms.
6. The process according to claim 1, wherein a) an epoxy compound of formula Ib ##STR00053## with R.sup.1b to R.sup.4b independently from each other representing hydrogen or an organic group with up to 50 carbon atoms whereby, alternatively, R.sup.2b, R.sup.4b and the two carbon atoms of the epoxy group may also together form a five to ten membered carbon ring and one of the groups R.sup.1b to R.sup.4b is a linking group to Z, n represents an integral number of at least 2 and Z represents a n-valent organic group, is used as starting material, b) the compound of formula Ib is reacted with a compound of formula II ##STR00054## wherein X is Cl or a group O—R.sup.5 with R.sup.5 representing a C1-to C4 alkyl group to obtain an adduct of formula IIIb ##STR00055## wherein R.sup.1b to R.sup.4b, Z and n have the meaning above; and c) the adduct of formula IIIb is reacted with a compound comprising anionic sulfur to a compound of formula IVb comprising at least two monothiocarbonate groups ##STR00056## wherein R.sup.1b to R.sup.4b, Z and n have the meaning above.
7. The process according to claim 6, wherein three of the R.sup.1b to R.sup.4b represent hydrogen and the remaining of R.sup.1b to R.sup.4b is the linking group to Z.
8. The process according to claim 7, wherein the linking group is a bond or a group CH.sub.2—O— or CH.sub.2—O—C(═O)—.
9. The process according to claim 8, wherein the group in the brackets of formula Ib is a glycidylether group which has the formula ##STR00057## or a glycidylester group which has the formula ##STR00058##
10. The process according to claim 6, wherein Z is a n-valent organic group with up to 50 carbon atoms and may comprise oxygen and n is an integral number from 2 to 5.
11. The process according to claim 6, wherein n is 2.
12. The process according to claim 11, wherein Z is a polyalkoxylene group of formula G1
(V—O—).sub.mV (G1) with V representing a C2-to C20 alkylene group and m being an integral number of at least 1 and wherein each of the two terminal alkylene groups V is bonded to the linking group, which is one of the groups R.sup.1b to R.sup.4b.
13. The process according to claim 11, wherein Z is a group of formula G2 ##STR00059## wherein W is a bi-valent organic group with at maximum 10 carbon atoms and R.sup.10 to R.sup.17 independently from each other represent H or a C1-to C4 alkyl group and wherein the two hydrogen atoms in the para position to W are replaced by the bond to the linking group, which is one of the groups R.sup.1b to R.sup.4b.
14. The process according to claim 13, wherein W is selected from the groups ##STR00060##
15. The process according to claim 2, wherein the monothiocarbonate of formula IVa is ##STR00061##
16. The process according to claim 5, wherein the R.sup.1a to R.sup.4a not being hydrogen represent CH.sub.2-O-C(═O)-R.sup.7, wherein R.sup.7 is a linear or branched alkyl or alkenyl group.
Description
EXAMPLES 1 TO 6, FIRST PART
Synthesis of β-Chloro Alkylchlorformates
(1) Epoxide was charged to a reactor and kept at −30° C. The molar amount of epoxide is listed in Table 1. 0.01 mol of tetra(n-butyl ammonium chloride were added per 1 mol of epoxide. Thereafter phosgene is added slowly as the reaction is exothermic. When adding the phosgene the temperature was kept via cooling at the temperature listed in the Table. The time of metering phosgene is listed in the Table. The total amount of phosgene was 1.1 mol per 1 mol of epoxide. When the addition of phosgene was completed the reaction mixture was further stirred for about (2 hours). Unreacted phosgene was removed by nitrogen stripping. No further work-up was necessary. The obtained β-chloro alkylchlorformates could be used directly in the next step which is the formation of the thiocarbonates.
(2) The epoxide, the obtained β-chloro alkylchlorformates and further details of the reaction are listed in Table 1.
(3) The β-chloro alkylchlorformates are obtained in form of two different structural isomers (stereoisomers) a and b
(4) ##STR00026##
(5) The selectivities regarding a and b are listed in the Table 1 as well. The total yield listed in Table 1 is based on the epoxide used as starting material.
(6) TABLE-US-00001 TABLE 1 β-chloro alkylchlorformates total β-chloro selectivity yield example epoxide alkylchlorformates T [° C.] a:b (a + b) [%] 1
(7) In examples 5 and 6 the yield and selectivity was determined by 1H-und 13C-NMR.
EXAMPLES 1 TO 6, SECOND PART
Synthesis of Monothiocarbonates
(8) Synthesis of compounds with one cyclic monothiocarbonate ring:
(9) The respective β-chloroalkyl chloroformate from examples 1 to 4 (50 g) and dichloromethane (50 mL) are placed in a 500 mL 4 neck round bottom flask equipped with a KPG crescent stirrer, dropping funnel, thermometer and a reflux condenser. The solution was cooled down to 0° C. with an ice bath before Na.sub.2S (1 equiv., 15 wt % aqueous solution) was slowly added, maintaining the temperature at 5° C. After the complete addition the ice bath was removed and the reaction mixture allowed to warm to room temperature. After stirring for 2 h the phases were separated and the aqueous phase was extracted with dichloromethane (2×50 mL). The solvent was removed from the combined organic phases under reduced pressure and the residual liquid purified by (Kugelrohr) distillation, yielding the desired cyclic thiocarbonate.
(10) TABLE-US-00002 TABLE 2 Selectivities and isolated yields (purities in brackets) of the various mono-thiocarbonates Area % of GC yield of β-chloro peak of monothio- alkylchlor- monothio- carbonate and formates carbonate in purity after from relation to area distillation example monothiocarbonate of all GC peaks in brackets 1 Methyl
(11) Synthesis of compounds with two cyclic monothiocarbonate rings:
(12) The respective bis-β-chloroalkyl chloroformiate (50 g) and dichloromethane (50 mL) are placed in a 500 mL 4 neck round bottom flask equipped with a KPG crescent stirrer, dropping funnel, thermometer and a reflux condenser. The solution was cooled down to 0° C. with an ice bath before Na.sub.2S (2 equiv., 15 wt % aqueous solution) was slowly added, maintaining the temperature at 5° C. After the complete addition the ice bath was removed and the reaction mixture allowed to warm to room temperature. After stirring for 2 h the phases were separated and the aqueous phase was extracted with dichloromethane (2×50 mL). The solvent was removed from the combined organic phases under reduced pressure yielding the desired cyclic monothiocarbonate.
(13) TABLE-US-00003 TABLE 3 Purities of the various compounds with two cyclic monothiocarbonate groups. β-chloro alkylchlor- Purity in % formates determined by from example monothiocarbonate 1H NMR 5 Bisphenol A
EXAMPLE 7
Alternative Process to Produce Monothiocarbonate of Example 3, Using NaSH and NaOH Instead of Na.SUB.2.S
(14) 1-Chloro-3-butoxy isopropyl chloroformate (20 g) is placed in a 250 mL 4 neck round bottom flask equipped with a KPG crescent stirrer, dropping funnel, thermometer and a reflux condenser. The liquid was cooled down to 0° C. with an ice bath before a solution of NaSH (1 equiv., 15 wt % aqueous solution) containing NaOH (1 equiv.) was slowly added, maintaining the temperature at 5° C. After the complete addition, the ice bath was removed and the reaction mixture allowed to warm to room temperature. The reaction was monitored via GC and after 5 min complete conversion of the chloroformate was observed. The phases were separated and the aqueous phase was extracted with dichloromethane (2×50 mL). The solvent was removed from the combined organic phases under reduced pressure yielding the desired cyclic thiocarbonate in >76% purity.
EXAMPLE 8
Synthesis of Methyacryl-Monothiocarbonate
(15) ##STR00045##
(16) First Step
(17) Glycidylmethacrylate (1 mol) was charged to a reactor and kept at −30° C. 0.008 mol of tetra(n-butyl ammonium chloride were added. Thereafter phosgene is added slowly as the reaction is exothermic. When adding the phosgene the temperature was kept via cooling at the temperature between 13-18° C. The total amount of phosgene was 1.3 mol per 1 mol of epoxide. When the addition of phosgene was completed the reaction mixture was further stirred for about (1.5 hours) while raising the temperature to 25° C. Unreacted phosgene was removed by nitrogen stripping. No further work-up was necessary. The obtained β-chloro alkylchlorformate could be used directly in the next step which is the formation of the monothiocarbonates.
(18) Second Step
(19) The β-chloroalkyl chloroformiate obtained (50 g) was placed in a 500 mL 4 neck round bottom flask equipped with a KPG crescent stirrer, dropping funnel, thermometer and a reflux condenser and dichloro-methane (250 g) was added. The liquid was cooled down to 0° C. with an ice bath before Na.sub.2S (1 equiv., 15 wt % aqueous solution) was slowly added, maintaining the temperature at 5° C. After the complete addition, the ice bath was removed and the reaction mixture allowed to warm to room temperature. After stirring for 4 h the phases were separated. GC analysis shows an initial purity of the methacryl-monothiocarbonate of 78%. Recrystallization from methanol results in a methacryl-monothiocarbonate with a purity of >98%.
(20) Details of the process are listed in Table 4:
(21) TABLE-US-00004 Yield Yield Of of β-chloro monothio- β-chloro alkylchlor- alkylchlorformate carbonate epoxide formates (%) Monothiocarbonate (%)
EXAMPLE 9
Solvent-Free Synthesis
(22) The respective β-chloroalkyl chloroformate from examples 1 or 3 (50 g) were placed in a 250 mL 4 neck round bottom flask equipped with a KPG crescent stirrer, dropping funnel, thermometer and a reflux condenser. The solution was cooled down to 0° C. with an ice bath before Na.sub.2S (1 equiv., 15 weight % aqueous solution) was slowly added, maintaining the temperature at 5° C. After the complete addition the ice bath was removed and the reaction mixture allowed to warm to room temperature. After stirring for 2 h the phases were separated and the aqueous phase was extracted with dichloromethane (2×50 mL). The solvent was removed from the combined organic phases under reduced pressure and the residual liquid purified by distillation, yielding the desired cyclic thiocarbonate.