PROCESS FOR PREPARING 4,4-DIMETYL-1,3-DIOXANE Russian patent published in 1994 - IPC

FIELD: chemical oil processing. SUBSTANCE: isobutylene as the isobutane-isobutylene fraction (IBF) is condensed together with aqueous formaldehyde (AF) at 90-110 C and pressure of 17-25 atm in the presence of oxalic acid. After distribution of the mixture between oil and aqueous phases, the aqueous layer is evaporated, aqueous formaldehyde is added to the residue and the resulting mixture is returned to condensation stage. The oil phase is treated in multistage fractionator to recover up to 90-95 % of the spent IBF at the first column and the residual of IBF is recovered together with trimethylcarbinol fraction at the second column plate. The last cut containing 3-10 % of 4,4-dimethyl-1,3- dioxane is returned to condensation stage. EFFECT: decreased content of high-boiling contaminating impurities in the stripped cut and decreased amount of the processed isobutylene. 1 tbl