Process for producing epoxides from olefinic compounds
View Patent ↗A process for producing an epoxide such as a cycloaliphatic diepoxide by the reaction of an olefin such as a cycloaliphatic diene with hydrogen peroxide (H 2 O 2 ) as an oxidant in the presence of a catalytic system under pH control for example at a pH of less than about 5. The present invention is advantageously used for the epoxidation of olefinic compounds such as olefins and aliphatic or aromatic dienes.
1. A process for producing an epoxidized product comprising
(a) mixing:
(i) an olefin containing two or more double bonds;
(ii) a transition metal catalyst; and
(iii) a solvent; and
(b) metering in, over a pre-determined period of time and at a regulated pre-determined first reaction temperature at a pH of less than about 5, a solution of:
(i) an excess of an aqueous hydrogen peroxide oxidant over the stoichiometric ratio of the hydrogen peroxide oxidant to the olefin; and
(ii) a buffering agent; and
(c) increasing the first reaction temperature by at least about 5 degrees C. to a second reaction temperature and continuing the reaction for a pre-determined period of time at said second reaction temperature to form an epoxidized product;
wherein the epoxidized product resulting from the reaction has an epoxide yield of greater than about 90% by weight of the total epoxidized product, a selectivity of greater than about 90% by weight of the total epoxidized product, a % monoepoxide of less than about 10% by weight of the total epoxidized product, and an OH-terminated by-products content of less than about 8% by weight of the total epoxidized product.
2. The process of claim 1 wherein the first and second reaction temperatures are within a range of from 10° C. to 100° C.
3. The process of claim 1 wherein the catalyst comprises a catalyst illustrated by the following chemical structure:
(R4N) 3 + {PO 4 [W(O)(O 2 ) 2 ] 4 } 3−
where R is a C1-C24 hydrocarbon chain.
4. The process of claim 1 wherein the buffering agent comprises a mixture of (a) a tungstate material to assist in maintaining the activity of the catalyst; (b) a phosphoric acid also to assist in maintaining the activity of the catalyst; and (c) an alkali metal salt to maintain the pH of the reaction mixture.
5. The process of claim 1 wherein the solvent is selected from the group comprising alkyl esters, halogenated hydrocarbons, cycloaliphatic hydrocarbons, aromatic hydrocarbons, alcohols and mixtures thereof.
6. The process of claim 1 wherein the first reaction temperature is in the range of −10° C. to 100° C., and said metering occurs over a period of from 1 minute to 300 minutes.
7. The process of claim 1 wherein the olefin comprises a diene compound.
8. An epoxidized product prepared by the process of claim 7 .
9. A coating comprising a cured epoxy resin obtained by curing a curable coating composition comprising (a) the epoxidized product of claim 8 , and (b) a curing agent.
10. The process of claim 7 wherein the diene compound comprises a cyclic diene compound.
11. An epoxidized product prepared by the process of claim 10 .
12. The process of claim 10 wherein the cyclic diene compound comprises a compound having the following formula:
13. An epoxidized product prepared by the process of claim 12 .
14. The epoxidized product of claim 13 containing less than about 8 percent by weight of the following oligomeric structure:
15. The process of claim 12 wherein the epoxidized product comprises an epoxy compound having the following formula:
16. An epoxidized product prepared by the process of claim 15 .
17. The epoxidized product of claim 16 containing less than about 8 percent by weight of the following oligomeric structure:
18. An epoxidized product prepared by the process of claim 1 .
19. A process of preparing a curable epoxy resin composition comprising mixing the epoxidized product of claim 18 and a curing agent.
20. A curable epoxy resin composition comprising the epoxidized product of claim 18 and a curing agent.
21. A cured epoxy resin obtained by curing the curable epoxy resin composition of claim 20 .