Alkyl glycoside refining bleaching method and equipment

Abstract

An alkyl glycoside refining bleaching method is as follows: a dealcoholized alkyl polyglycoside crude product is prepared into a water solution with certain concentration, then at a certain temperature and under a certain operation pressure, a liquid film with a certain thickness is formed by the alkyl polyglucoside water solution, gas-liquid two-phase membrane contact of the liquid film and an oxidative gas is performed, the oxidative gas is a bleaching agent, under the effect of the bleaching agent, color groups in the alkyl polyglucoside water solution are oxidized to achieve the purpose of bleaching. The method adopts gas-liquid two-phase membrane contact, so that contact area is large, the contact is more full, the bleaching more thorough, and bleaching time is shortened; to be more important, the to-be-bleached alkyl polyglucoside water solution flows down along an overflow wall, so that the content of the gas dissolving in the alkyl polyglycoside water solution can be reduced, internal molecular collision and liquid agitation effect of the alkyl polyglycoside water solution can be reduced, and no a lot of bubbles are produced. The alkyl polyglycoside which is a surface active agent has a very important significance to reduce the generation of foams.

Description

technical field [0001] The invention belongs to the field of preparation technology of alkyl glycosides, and in particular relates to a new technology and equipment for preparing alkyl glycosides. Background technique [0002] Alkyl glycoside (APG) is a new type of nonionic surfactant that has appeared since the 1990s. It is formed by the dehydration of natural renewable resources fatty alcohols and sugar compounds (mostly glucose) under an acidic catalyst. It has many characteristics of non-ionic surfactants and anionic surfactants, can be well compounded with any surfactant, and is highly efficient, non-toxic, non-irritating to the skin, fully biodegradable, and synergistic. obvious features. Therefore, it is widely used in various fields of people's life. [0003] There are two main methods for the industrial production of alkyl glycosides. One is the "two-step method" used in the early days, also known as the "transglycosylation method or acetal exchange method", that ...

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Problems solved by technology

[0005] But this kind of bleaching method causes the utilization rate of hydrogen peroxide to be low because the decomposition of hydrogen peroxide itself, can make the aqueous solution of alkyl glycoside produce stable foam simultaneously and make bleaching process be difficult to carry out (hydrogen peroxide decomposes and produces oxygen, and oxygen emerges from solution and makes solution form a large amount Bubbles), in addition, there is an excessive amount of undecomposed hydrogen peroxide in the bleached product, resulting in unstable color, and the product is easy to turn yellow during storage

U.S. Patent (US6166189) proposed to use lithium borohydride, or sodium borohydride, potassium borohydride to treat the bleached alkyl glycoside aqueous solution to remove excess hydrogen peroxide and make the product stable, but the metal borohydride is expensive and the production cost is high. Not suitable for industrial production

At the same time, there are almost no relevant patent records about the equipment used in the bleaching process of the alkyl glucoside aqueous solution. The conventional method is to directly add hydrogen peroxide into the bleaching kettle containing the alkyl glucoside. The oxygen produced by the decomposition causes the aqueous solution of alkyl glycosides to generate a large amount of foam, which often requires a large space for bubble breaking or an effective breaking method, which greatly reduces the bleaching efficiency, and is also a technical problem that is difficult for relevant practitioners in this industry to solve

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