Azacyclocarbene metal coordination polymer and preparation method thereof, and application of azacyclocarbene metal coordination polymer as catalyst

Abstract

The invention specifically relates to an azacyclocarbene metal coordination polymer and a preparation method thereof, and application of the azacyclocarbene metal coordination polymer as a catalyst, belonging to the technical field of preparation and application of heterogeneous catalysts. The azacyclocarbene metal coordination polymer provided in the invention has a general structural formula (I) and can be prepared by reacting a bis(imidazole) salt with a metal precursor under alkaline conditions and carrying out coordination assembling. The azacyclocarbene metal coordination polymer is applicable to catalysis of oxydehydrogenation of a variety of alcohols and derivatives thereof, carbohydrate compounds, cellulose or lignin and to high-efficiency preparation of lactic acid and derivatives thereof. The novel self-loaded catalytic system integrates the advantages of homogeneous catalysis and heterogeneous catalysis, and can realize high-efficiency, high-selectivity and considerable conversion of biomass polyol raw materials under mild conditions; and the catalyst has the advantages of high-efficiency recovery, repeated usability, etc., and has good application prospect in preparation of lactic acid and hydrogen by using industrial catalysis approaches.

Description

technical field The invention belongs to the technical field of heterogeneous catalyst preparation and application, and specifically relates to a novel nitrogen heterocyclic carbene metal coordination polymer, its preparation method and its application as a catalyst. Background technique Polyols and their derivatives are not only widely found in nature, but also can easily obtain some low-cost natural small molecular compound. Through the dehydrogenation conversion of small molecular polyols, not only can some high value-added fine chemical products be prepared conveniently, but also has great significance for solving the related problems faced by the current energy industry that relies heavily on petroleum. At present, the method of using natural polyols and biodiesel to prepare polyol waste into high value-added platform molecular lactic acid mainly uses biological fermentation. Although the fermentation method has the advantages of good selectivity and mild conditions, ...

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Problems solved by technology

Silica-supported gold-platinum bimetallic heterogeneous catalysts were first used in this field, but this type of supported inorganic nanocatalytic system still has low conversion rate, poor reaction selectivity, high reaction temperature, and the need to use a large amount of powerful catalysts. Alkali and other issues

It was not until the beginning of this year that the use of homogeneous bisphosphine pincer ruthenium catalysts for the preparation of lactic acid from glycerin was reported, but the highest selectivity of 60% for the production of lactic acid can only be obtained. In addition to the low conversion rate, the reaction system is still Various by-products are produced

At the same time, phosphine ligands are difficult to apply to actual production due to many factors such as complex synthesis, high price, instability to air and water, and environmental unfriendliness.

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