Preparation of glycerol tert-butyl ethers
A process for making glycerol di-tert-butyl ethers is disclosed. In one aspect of the invention, glycerol and isobutylene react in the presence of a β-zeolite having a silicon to aluminum ratio greater than 150. In another aspect, the etherification is performed in the presence of a β-zeolite and added tert-butyl alcohol. Each process selectively provides glycerol di-tert-butyl ethers while reducing the generation of isobutylene dimers and trimers. Utilizing both aspects of the inventive process simultaneously affords a diether product mixture containing less than 5 wt. % of isobutylene oligomers.
1 . A process which comprises reacting glycerol and isobutylene in the presence of a β-zeolite having a silicon to aluminum ratio greater than 150 to give a product mixture comprising a glycerol di-tert-butyl ether.
2 . The process of claim 1 wherein the β-zeolite has a silicon to aluminum ratio within the range of 200 to 500.
3 . The process of claim 1 wherein the reaction is performed in the presence of added tert-butyl alcohol.
4 . The process of claim 1 wherein the reaction is performed at a temperature within the range of 30° C. to 150° C.
5 . The process of claim 1 wherein the product mixture comprises glycerol tert-butyl ethers, at least 75 wt. % of which is the di-tert-butyl ether.
6 . The process of claim 1 wherein the product mixture comprises less than 15 wt. % of isobutylene oligomers.
7 . A process which comprises reacting glycerol and isobutylene in the presence of a β-zeolite and added tert-butyl alcohol to give a product mixture comprising a glycerol di-tert-butyl ether.
8 . The process of claim 7 wherein the β-zeolite has a silicon to aluminum ratio within the range of 200 to 500.
9 . The process of claim 8 wherein the product mixture comprises less than 5 wt. % of isobutylene oligomers.