Method for synthetizing 2,6-dimethylnaphthalene with methanol, C10 arene and 2-methylnaphthalene through alkylation

Abstract

The invention relates to a method for synthetizing 2,6-dimethylnaphthalene with methanol, C10 arene and 2-methylnaphthalene through alkylation. The method uses the mixture of 2-methylnaphthalene, methanol and C10 arene which is C10 aromatic mixture mainly containing tetramethylbenzene and is a byproduct obtained from the aromatic device, as raw material to prepare 2,6-dimethylnaphthalene through alkylation in the existence of a molecular sieve catalyst. In particular, methanol is used as the raw material a, C10 arene is used as the raw material b and 2-methylnaphthalene is used as the raw material c; the raw materials are used to prepare the raw material mixture, wherein the ratio of a to c is 1-3:1(mol / mol) and the ratio of b to c is 1-6:1(mol / mol); and 2,6-dimethylnaphthalene is synthetized through alkylation in the existence of the molecular sieve catalyst under the conditions that the reaction temperature is 380-500 DEG C, the reaction pressure is 0-6.0MPa and the reaction air speed is 0.1-2h<-1>. By adopting the method, the C10 arene resource which is the byproduct with low value can be utilized, methanol with low price and rich source is introduced in the reactant and the reaction activity, selectivity and reaction stability can be effectively increased.

Description

technical field [0001] The invention relates to a method for synthesizing 2,6-dimethylnaphthalene by alkylating methanol, carbon ten aromatic hydrocarbons and 2-methylnaphthalene. Background technique [0002] 2,6-Dialkylnaphthalene (2,6-DANs) is an important precursor for the production of new high-performance polyester materials, and 2,6-DMN is considered to be the most promising chemical, which can be oxidized into 2,6-naphthalene dicarboxylic acid, which is a raw material for the production of the high-performance material polyethylene naphthalate (PEN). At present, the high price of PEN has restricted its large-scale entry into the market, and the main factor affecting the price of PEN is that the existing production process of 2,6-dimethylnaphthalene is complicated and the production cost is relatively high. The traditional BP-Amoco process is complicated, has many steps, low yield, and the by-products cause serious environmental pollution (Asian Chemical News, Nov. 1...

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Problems solved by technology

Kobe Steel and ExxonMobil Corporation (M Motoyuki, K Yamamoto, S Vishwanath, et al.US, Patent.6011190 (2000).) have reported a kind of alkylation of methylnaphthalene and methanol by MCM-22 zeolite catalyst, followed by In another reactor, naphthalene and methyldecalyl are transferred or isomerized, and you separate and circulate many times to synthesize the process of 2,6-dimethylnaphthalene, but because of its many process steps, large material consumption and high production cost also very high

WO02060581 reported that (L.D.Lillwita, C.Song) passed FeF 3 and NH 4 HF 2 Carry out the alkylation reaction of methylnaphthalene and methanol on the modified HZSM-5 molecular sieve to directly synthesize 2,6-dimethylnaphthalene, which can obtain 60% selectivity of 2,6-dimethylnaphthalene and 1.8-2.2 , the ratio of 6- / 2,7-dimethylnaphthalene isomers, but the synthesis yield of 2,6-dimethylnaphthalene is still low

In addition, it has been recently reported (C. Zhang, X.W. Guo, C.S. Song et al. Catalysis Today 149 (2010) 196-201.) that on HZSM-5 molecular sieves modified by ethyl tetrasilicate and steam treated, respectively Obtained 5.3% and 7.6% 2,6-dimethylnaphthalene yields, and think on raising 2,6- / 2, on the ratio of 7-dimethylnaphthalene isomers, the acidity of zeolite molecular sieve adjusts specific channel The size control is more favorable, but the accompanying side reactions are more serious, and the catalyst deactivates quickly

[0003] At present, although the product selectivity of the synthesis of 2,6-dimethylnaphthalene by the alkylation reaction of methylnaphthalene and methanol on molecular sieves can be improved by modifying the acidity and structure of molecular sieves, the product selectivity of 2,6-dimethylnaphthalene The yield is low and the stability of the catalyst is not good, which affects the industrial application of this process

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