Abstract: A process for dehydrating methanol to dimethyl ether product in the presence of a catalyst and a promoter, wherein the catalyst is at least one aluminosilicate zeolite, wherein: —the aluminosilicate zeolite is selected from: (i) a zeolite having a 2-dimensional framework structure comprising at least one channel having a 10-membered ring, and having a maximum free sphere diameter of at least 4.

Abstract: A process for dehydrating methanol to dimethyl ether product in the presence of a catalyst and a promoter, wherein the catalyst is at least one aluminosilicate zeolite, and the promoter is selected from one or more compounds of Formula I: (I) wherein each of X and any or all of the Y's may independently be selected from hydrogen, halide, a substituted or unsubstituted hydrocarbyl substituent, or a compound of the formula —CHO, —CO2R, —COR, or —OR, where R is hydrogen or a substituted or unsubstituted hydrocarbyl substituent, and wherein the molar ratio of promoter to methanol is maintained at less than 1.

Abstract: A process the dehydration of methanol to dimethyl ether in the presence of a solid Brønsted acid catalyst selected from aluminosilicate zeolites which have a maximum free sphere diameter of greater than 3.67 Angstroms and heteropolyacids and a promoter selected from methyl formate, dimethyl oxalate and dimethyl malonate and the molar ratio of promoter to methanol is maintained at less than 1.

Abstract: A process for dehydrating methanol to dimethyl ether product in the presence of an aluminosilicate zeolite catalyst and a promoter selected from (i) aldehyde of formula R1CHO (Formula I) in which R1 is hydrogen, a C1-C11 alkyl group or a C3-C11 alkyl group in which 3 or more carbon atoms are joined to form a ring; or (ii) acetal derivative of an aldehyde of Formula I; and the molar ratio of promoter to methanol is maintained at 0.1 or less.

Abstract: A process the dehydration of methanol to dimethyl ether in the presence of a solid Br?nsted acid catalyst selected from aluminosilicate zeolites which have a maximum free sphere diameter of greater than 3.67 Angstroms and heteropolyacids and a promoter selected from methyl formate, dimethyl oxalate and dimethyl malonate and the molar ratio of promoter to methanol is maintained at less than 1.