Dimethyl acetone-1,3-dicarboxylate (Dimethyl acetone-1,3-dicarboxylate or 3-oxo-pentanedioic acid, dimethyl ester, CAS:1830-54-2) is a kind of medical science intermediate, once be applied to the synthetic of coromegine, mountain Liang Rong alkali at twentieth century, have certain anti-microbial activity because finding it this century, is widely used in again the synthetic of antibiotic medicine.

Preparation

Dimethyl acetone-1,3-dicarboxylate is obtained by β-ketoglutaric acid and methanol esterification, and it is raw material that synthetic β-ketoglutaric acid generally adopts Citric Acid, usp, Anhydrous Powder, in the situation that oleum exists, oxidative decarboxylation makes.Oleum is high to equipment requirements, production security is poor, is unfavorable for suitability for industrialized.

summary of the invention

The object of the invention provides the preparation method of the dimethyl acetone-1,3-dicarboxylate that a kind of technique is simple, safe, cost is low, pollution is few.

The technical solution used in the present invention is:

A kind of preparation method of dimethyl acetone-1,3-dicarboxylate, described method comprises:

(1) citric acid and 98% vitriol oil be 49～52 ℃ of lower stirring reactions 1～2 hour, after reaction finishes reaction solution dripped to stir in the entry to be cooled to below 10 ℃, and crystallize out filters, filter cake washing, obtains β-ketoglutaric acid; Used citric acid, sulfuric acid, quality ratio are 1: 1～3: 1～3; The waste gas that produces in this reaction process is carbon monoxide.

It is as follows that this step relates to reaction formula:

(2) get and drip anhydrous methanol and sulfur oxychloride in the β-ketoglutaric acid that step (1) makes, back flow reaction 1～3 hour, reaction finishes afterreaction liquid through separation and purification, obtain described dimethyl acetone-1,3-dicarboxylate, described β-ketoglutaric acid, anhydrous methanol, sulfur oxychloride mass ratio are 1: 3～6: 0.5～2.0.