FIELD: chemistry.
SUBSTANCE: present invention relates to a method of processing by-products of the synthesis of 4,4-dimethyl-1,3-dioxane formed during the preparation of 4,4-dimethyl-1,3-dioxane from isobutylene and formaldehyde and/or substances that are their sources upon decomposition on an aluminosilicate-containing catalyst at a temperature of 400-480 °С in the presence of water vapor. The method includes preliminary mixing of the initial product with an aqueous layer of liquid-phase synthesis of isoprene, subsequent hydrolysis of the resulting mixture at an elevated temperature, evaporation of the resulting hydrolyzate in a stream of water vapor at elevated temperature and pressure and supply of the resulting gas for catalytic decomposition. At the same time, a fraction of by-products from the stage of synthesis of 4,4-dimethyl-1,3-dioxane with a boiling point of 140-170 °С at a residual pressure of 20 mm Hg undergoes hydrolysis. The fraction of by-products is mixed with water from the stage of isoprene synthesis in the ratio equal to (2-6): 1. The resulting mixture undergoes hydrolysis at a temperature of 160-180 °С and a pressure from atmospheric pressure to 1.0 MPa.
EFFECT: invention increases the total yield of useful products, reduces coke deposition and increases the conversion of heavy residue up to 88%.
1 cl, 4 ex
