Method for preparing olefin compound based on catalyst obtained by compounding carbon tubes and transition metals

Abstract

The invention discloses a method for preparing an olefin compound based on a catalyst obtained by compounding carbon tubes and transition metals. The method comprises the following steps: preheating and vaporizing an alkane compound, mixing the compound with carrier gas, and carrying out a dehydrogenation reaction in a reactor under the action of a catalyst; and collecting the olefin compound after condensation, wherein the catalyst contains 5-30wt% of transition metals/transition metal oxides and 70-95wt% of carbon tubes. The method is used for preparing aliphatic olefin compounds and aromatic olefin compounds, the catalyst compounded based on the carbon tubes and transition metal elements/transition metal oxides is stable to water, air and heat, the catalytic activity is invariable after the continuous experiment of over 150 hours, continuous operation can be realized, activation is not needed, and the catalyst is economic and convenient. According to the method disclosed by the invention, when the catalyst is applied to ethylbenzene gaseous phase direct dehydrogenation so as to prepare styrene, the conversion rate of the alkane compound is not less than10 percent, and the selectivity of the olefin compound can be more than or equal to 97 percent.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a method for preparing olefin compounds based on a catalyst compounded by carbon tubes and transition metals. Background technique [0002] Olefin compounds are important chemical raw materials, which are divided into aliphatic olefin compounds and aromatic olefin compounds. Propylene / isobutylene mainly comes from the co-production or by-product of steam cracking and fluid catalytic cracking in refineries, and can be widely used in the synthesis of polymers, gasoline additives, rubber and various chemical intermediates. With the increasing demand for low-carbon olefins, the traditional production process is difficult to meet market demand. The development of the process of producing low-carbon alkenes from low-carbon alkanes is of great significance for making full use of low-carbon alkanes to open up new sources of alkenes. [0003] The catalytic reaction of dehydrogenation of...

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Problems solved by technology

Subsequently, the D.S.Su research group reported a two-step synthesis of nano-diamond / CNT-SiC carbon-based catalysts, selecting macroporous SiC foam with high thermal conductivity and mechanical stability as a carrier, and wrapping it on the surface of SiC foam by chemical vapor deposition. A layer of carbon tubes, and then use ultrasonic-assisted impregnation to load commercial nanodiamonds on the substrate. Although the prepared catalyst has a high conversion rate, the preparation process of the catalyst is complicated and the cost is high. In addition, the reported The stability is only 20 hours (Chem.Commun.,2014,50,7810-7812)

Another example is the nanodiamond / carbon nitride hybrid material prepared by Z.K.Zhao et al. (J.Mater.Chem.A.2014, 2, 13442-13451) is obtained by mixing melamine and nanodiamond and calcining to different temperatures. Melamine introduces heteroatom N to improve its catalytic performance, but it requires strong oxidative acid explosion treatment in the preparation process of nanodiamond, which is extremely unfriendly to the environment, and its catalytic stability is only reported at 20 hours.

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