A process for the co-production of acetic acid and dimethyl ether with reduced formic acid content by distilling a mixture comprising dimethyl ether, methanol and methyl formate; separating methyl formate from the mixture to recover dimethyl ether and methanol; and catalytically reacting the methanol and methyl acetate to produce a reaction product of acetic acid an dimethyl ether.

The present invention provides 5-(2-butyl-1,3-dioxolan-2-yl)-1-methylpentyl acetate of the following formula (1).

The present invention further provides the aforesaid 5-(2-butyl-1,3-dioxolan-2-yl)-1-methylpentyl acetate (1), the process comprising the step of subjecting an organic magnesium compound (2) of the following general formula (2), wherein X.sup.1 represents a halogen atom or a 3-(2-butyl-1,3-dioxolan-2-yl) propyl group, to a nucleophilic addition reaction with propylene oxide of the following formula (3) and then reacting with an acetylating agent of the following general formula (4), wherein X.sup.2 represents a halogen atom, an acetoxy group, a methoxy group, or an ethoxy group, to form 5-(2-butyl-1,3-dioxolan-2-yl)-1-methylpentyl acetate (1).

##STR00001##

The present invention provides 5-(2-butyl-1,3-dioxolan-2-yl)-1-methylpentyl acetate of the following formula (1).

The present invention further provides the aforesaid 5-(2-butyl-1,3-dioxolan-2-yl)-1-methylpentyl acetate (1), the process comprising the step of subjecting an organic magnesium compound (2) of the following general formula (2), wherein X.sup.1 represents a halogen atom or a 3-(2-butyl-1,3-dioxolan-2-yl) propyl group, to a nucleophilic addition reaction with propylene oxide of the following formula (3) and then reacting with an acetylating agent of the following general formula (4), wherein X.sup.2 represents a halogen atom, an acetoxy group, a methoxy group, or an ethoxy group, to form 5-(2-butyl-1,3-dioxolan-2-yl)-1-methylpentyl acetate (1).

##STR00001##