A kind of synthetic method of small molecule pickling auxiliary tanning agent

Abstract

Provided is a synthetic method of a micromolecule pickling auxiliary tanning agent. Aniline-2,5-disulfonic acid and glyoxylic acid are added into a reactor provided with a stirrer, a thermometer and a reflux condensing tube and then are stirred evenly at a normal temperature, then the pH of the system is adjusted to be 4-5 through alkaline water, the temperature of the system is increased to 90-100 DEG C, reaction is conducted for 6 hours, the system is cooled to be at the normal temperature, the solid content is controlled to be 50% through distilled water, and then the micromolecule pickling auxiliary tanning agent is obtained. By the adoption of the pickling auxiliary tanning agent, high-exhaustion chrome tanning is achieved in the process of achieving less-acid salt-free pickling.

Description

technical field [0001] The invention belongs to the technical field of leather pickling auxiliary agents, and in particular relates to a synthesis method of a small-molecule pickling auxiliary tanning agent. Background technique [0002] In the past ten years, no / less salt pickling auxiliaries have become one of the hot spots in the development of green tanning chemicals. In order to suppress the expansion of the pickle hide, a large amount of neutral salt is added to the pickling tanning bath, causing serious environmental pollution. At the end of 2013, the "Water Pollution Discharge Standards for Tannery and Fur Processing Industry" promulgated by the national environmental protection department - A limit has been carried out, requiring the existing tanning enterprises to have Cl - The emission concentration limit is 3000mg / L, and the total chromium is 1.5mg / L. Such high environmental protection requirements have seriously threatened the normal operation and healthy deve...

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Problems solved by technology

However, this additive can only be used to improve the chromium absorption rate and cannot solve the problem of salt used for pickling (Chen Wei, Qiang Xihuai, Sun Zhe, et al. Research on the auxiliary tanning performance of polycarboxypolyurethane blocked by sodium bisulfite[J]. Leather Science and Engineering, 2016, 02:9-13+19.)

Qiang Xihuai and others used glyoxylic acid to modify collagen, introduced a large number of carboxyl groups on the side chain of collagen fibers, increased the cross-linking sites of chrome tanning, and at the same time, it can also play a role in reducing salt to a certain extent during the pickling process , but the reduction of neutral salt is limited (Qiang Xihuai, Li Wenxin, Yu Congzheng, etc. Research on the application process of glyoxylic acid-assisted chrome tanning [J]. China Leather, 2002, 07:28-32.)

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