Process for producing glucurolactone

Abstract

The invention relates to a production process for glucurono lactone, and comprises the working procedures of oxidization, hydrolization, concentration, esterification, crystallization, centrifugation, refinement, and product finishing. The invention is mainly and technically characterized in that the oxidation working procedure comprises the steps of completely adding amylum into nitric acid, insulating for above 5 hours at the temperature ranging from 37 to 43 DEG C, adding water, rising the temperature to 50-90 DEG C, and charging compressed air to react for 2 to 4 hours, so as to ensure the amylum to be fully oxidated; the concentration end point of hydrolysate is the baume degree being larger than or equal to 44 to 50, so that free water in solution is descended to the lower content to be favorable for lactonization in the next step; single esterification in the esterification working procedure is changed into multiple esterification, and the water generated in the esterification is carried over with water-carrying agent after the esterification, so that the repeated esterification is performed more thoroughly; the crystallization working procedure comprises the steps that alcohol is not required to be added for dilution, thereby ensuring a crystallization mother liquor system to be improved, and being favorable for the extraction of glucurono lactone crystallization, and also being favorable for distilling acetic acid out of parting mother liquor. The product total yield rate of the invention is enhanced to 14 to 15 percent (W / W), the consumption is reduced, the pollution is reduced, and the production cost is reduced.

Description

technical field [0001] The invention belongs to the manufacturing method of fine chemical products—medicine intermediates, and in particular relates to a production method of glucuronolactone. Background technique [0002] There are many production methods of glucuronolactone in my country, but the mature technology used for production mainly adopts the following scheme, and the specific process is introduced as follows: [0003] (1) oxidation process; [0004] Add 340-350L of 60% nitric acid into the oxidation kettle at one time, raise the temperature to 50-52°C under stirring and stop heating, then use about 5kg of starch and 2.6kg of NaNO 2 Mix well, then feed into the oxidation kettle at one time through the feeding port as an initiator, and then cast starch at the following time and temperature: [0005] Time: (minutes): 0 20 40 60 80 [0006] Temperature: (°C): 51-52 47-48 44-45 40-43 40-41 [0007] Feeding amount (kg): 75 75 70 50 50 [0008] In the item of time,...

AI Technical Summary

Problems solved by technology

[0028] (1) During the whole oxidation process, the starch is solid-liquid reaction with nitric acid in the state of powder block or paste, so that the starch cannot be effectively transformed into carboxylated starch, and the conversion rate of starch into carboxylated starch is determined by analysis Very low, so the effective component of the hydrolyzate-glucuronic acid conversion rate is less than 30% during hydrolysis and a large amount of glucose-based liquid is generated, which is not conducive to the subsequent reactions of various parts

[0029] (2) The end point of the hydrolysis solution is less than, so that the solution system also contains more free water, which is unfavorable for the carrying out of lactonization, so the degree of esterification is not high under the above-mentioned process conditions

[0030] (3) In the esterification liquid system, it is a viscous liquid composed of a large amount of polysaccharides, water, ethanol, acetic acid and other substances, which is not conducive to crystallization, resulting in low product yield

[0031] (4) Since the crystallized mother liquor is dissolved together by various solvents, it cannot be recycled and causes great pollution to the environment