Toluene methylation method for increasing yield of o-xylene and p-xylene

Abstract

The invention relates to a toluene methylation method for increasing the yield of o-xylene and p-xylene, and mainly solves the problems that a dimethylbenzene product which is distributed in a balanced way can only be obtained by the methylation of toluene and the selectivity of o-xylene and p-xylene is relatively low in the prior art. The problems are well solved by the technical scheme that toluene and methanol are taken as raw materials which are contacted with a catalyst for toluene methylation reaction through a fixed bed reactor under hydrogenation condition, wherein reaction conditions are that: a) the reaction temperature is 300 to 500 DEG C, the reaction pressure is 0.1 to 5.0MPa, the molar ratio of hydrogen to aromatic hydrocarbon is 0.2-8, and the feeding space velocity is 1 to 10.0h<-1>; and b) the used catalyst comprises the following components in part by weight: 5 to 95 parts of H-mordenite (NaHMor) containing 0.08 to 2.8 percent of sodium ions, and 95 to 5 parts of adhesive; and the method can be used for the industrial production of o-xylene and p-xylene.

Description

technical field [0001] The invention relates to a toluene methylation method for increasing the production of o-xylene and p-xylene. Background technique [0002] Ortho-xylene is an important chemical intermediate, mainly used in the production of phthalic anhydride (commonly known as phthalic anhydride). Phthalic anhydride is mainly used in the production of plasticizers and alkyd resins, unsaturated resins, polyester polyols, and polyester resins, and can also be used as intermediates in the production of saccharin, pigments, dyes, medicines, and pesticides. With the continuous expansion of the application of downstream products of phthalic anhydride, especially with the development of my country's construction industry, transportation, electronics, and aviation industries, the wide application of anti-corrosion materials, and the large-scale use of unsaturated polyester resins and alkyd resins, the market's demand for raw materials The demand for o-xylene also shows an in...

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Problems solved by technology

In patents CN 1762593A, US4067920, US 4011276, US 5367099 and US 5607888, it is proposed to modify the ZSM-5 molecular sieve structure, that is, to reduce the pore size and shield the acidic active sites on the outer surface, and to prepare selective toluene disproportionation or methylation Catalysts, the above-mentioned patents are all aimed at improving the selectivity of p-xylene, and there are cumbersome process steps, high price of organosilicon modifiers used, complex structure, or large amount, expensive solvents used, or the need to add precious metals to the catalyst waiting for improvement

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