METHOD FOR THE PREPARATION OF THIOCARBONATES

Abstract

A process can be used for the preparation of a compound with at least one five-membered cyclic monothiocarbonate group. The process involves a) using a compound with at least one epoxy group as starting material; b) reacting the compound with phosgene or an alkyl chloroformate, thus giving an adduct; and c) reacting the adduct with a compound containing anionic sulfur, thus obtaining the compound with at least one five-membered cyclic monothiocarbonate group.

Claims

1-25. (canceled)

26. A compound of formula IVa: ##STR00049## wherein two or three of R.sup.1a to R.sup.4a represent hydrogen and R.sup.1a to R.sup.4a not being hydrogen represent a group CH.sub.2—O—R.sup.6, CH.sub.2—O—C(═O)—R.sup.7, or —CH.sub.2—NR.sup.8R.sup.9, with R.sup.6 to R.sup.9 being a linear or branched alkyl group, alkoxy group, polyalkoxy group, or alkenyl group with at maximum 30 carbon atoms.

27. The compound according to claim 26, wherein the compound is a mixture of two structural isomeric compounds A and B of formula IVa, wherein isomeric compound A is a compound with R.sup.1a being a group CH.sub.2—O—R.sup.6, CH.sub.2—O—C(═O)—R.sup.7, or —CH.sub.2—NR.sup.8R.sup.9, and R.sup.2a, R.sup.3a, and R.sup.4a are hydrogen, wherein isomeric compound B is a compound with R.sup.3a being a group CH.sub.2—O—R.sup.6, CH.sub.2—O—C(═O)—R.sup.7, or —CH.sub.2—NR.sup.8R.sup.9, and R.sup.1a, R.sup.2a, and R.sup.4a are hydrogen, and wherein the mixture consists of 90 to 99.9% by weight of isomeric compound A and 0.1 to 10% by weight of isomeric compound B, based on a sum of isomeric compounds A and B.

28. The compound according to claim 26, wherein R.sup.2a to R.sup.4a represent hydrogen and R.sup.1a is a group —CH.sub.2—O—R.sup.6, —CH.sub.2—O—C(═O)—R.sup.7, or —CH.sub.2—NR.sup.8R.sup.9, with R.sup.6 to R.sup.9 being a C.sub.1 to C.sub.14 alkyl group.

29. A compound of formula IVb: ##STR00050## 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 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.

30. The compound according to claim 29, wherein the linking group is a bond or a group CH.sub.2—O— or CH.sub.2—O—C(═O)—.

31. The compound according to claim 29, wherein the group in the brackets of formula IVb is a glycidylether group which has the formula ##STR00051## or a glycidylester group which has the formula ##STR00052##

32. The compound according to claim 29, wherein n is 2 and Z is a polyalkoxylene group of formula G1:
(V—O—).sub.mV   (G1), with V representing a C.sub.2 to C.sub.20 alkylene group and in 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 R.sup.1b to R.sup.4b.

33. The compound according to claim 29, wherein n is 2 and Z is a group of formula G2: ##STR00053## with W representing a bi-valent organic group with at maximum 50 carbon atoms, 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 R.sup.1b to R.sup.4b.

34. The compound according to claim 33, wherein W is selected from the group consisting of ##STR00054##

35. The compound according to claim 29, wherein Z is an alkylene group.

36. The compound according to claim 26, wherein the compound of formula IVa is ##STR00055##

37. The compound according to claim 26, wherein 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

[0184] 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.

[0185] The epoxide, the obtained β-chloro alkylchlorformates and further details of the reaction are listed in Table 1.

[0186] The β-chloro alkyichlorformates are obtained in form of two different structural isomers (stereoisomers) a and b

##STR00026##

[0187] 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.

TABLE-US-00001 TABLE 1 β-chloro alkylchlorformates selec- total exam- T tivity yield ple epoxide β-chloro alkylchlorformates [° C.] a:b (a + b) [%] 1 [00027] [00028] 15-20 90:10 >99 2 [00029] [00030] 15-20 98.5:1.5   97 3 [00031] [00032] 15-20 96:4   96 4 [00033] [00034] 15-30 >98 >99 5 [00035] [00036] 35-40 ca. 95:5  >99 6 [00037] [00038] 10-20 >95:5   >99

[0188] In examples 5 and 6 the yield and selectivity was determined by 1H- and 13C-NMR.

EXAMPLES 1 TO 6, SECOND PART

Synthesis of monothiocarbonates

[0189] Synthesis of compounds with one cyclic monothiocarbonate ring:

[0190] The respective β-chloroalkyl chioroformate 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.

TABLE-US-00002 TABLE 2 Selectivities and isolated yields (purities in brackets) of the various mono-thiocarbonates β-chloro yield of monithio- alkylchlor- Area % of GC carbonate and formates peak of monothio- purity after from carbonate in relation distillation in example monothiocarbonate to area of all GC peaks brackets 1 [00039] 84% 69% (>97%) 2 [00040] 86% 77% (>95%) 3 [00041] 92% 83% (>97%) 4 [00042] 66% 20% (80%) 

[0191] Synthesis of compounds with two cyclic monothiocarbonate rings:

[0192] 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.

TABLE-US-00003 TABLE 3 Purities of the various compounds with two cyclic monothiocarbonate groups. β-chloro Purity in % alkylchlorformates determined by from example monothiocarbonate 1H NMR 5 [00043]  80% 6 [00044] >99%

EXAMPLE 7

Alternative Process to Produce Monothiocarbenate of Example 3, Using NaSH and NaOH Instead of Na.SUB.2.S

[0193] 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 agueous 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

[0194] ##STR00045##

[0195] First Step

[0196] 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 alkylchlorforrnate could be used directly in the next step which is the formation of the monothiocarbonates.

[0197] Second Step

[0198] 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 rnethacryl-monothiocarbonate of 78%. Recrystallization from methanol results in a methacryl-monothiocarbonate with a purity of >98%.

[0199] Details of the process are listed in Table 4:

TABLE-US-00004 Yield Of Yield of β-chloro monothio- β-chloro alkylchlorformate carbonate epoxide alkylchlorformates (%) Monothiocarbonate (%) [00046] [00047] 98 [00048] 75

EXAMPLE 9

Solvent-Free Synthesis

[0200] 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.