37 results about "2,6-Dimethylnaphthalene" patented technology

The invention provides a method for preparing 2,6-dimethylnaphthalene by catalyzing naphthalene alkylation reaction with CoAPO-11 molecular sieve, relates to a method for preparing 2,6-dimethylnaphthalene, and is used for solving the problems that the traditional catalyst cannot simultaneously have high activity and high selectivity of 2,6-dimethylnaphthalene. The method comprises the steps of: activating the CoAPO-11 molecular sieve synthesized by an electrical heating method or microwave heating method for 2h, then mixing with naphthalene, alkylation reagents and solvent to prepare raw material liquid, and carrying out alkylation reaction to obtain 2,6-dimethylnaphthalene. According to the invention, the synthesized CoAPO-11 molecular sieve has higher catalytic reaction activity on naphthalene alkylation reaction, and higher selectivity of 2,6-dimethylnaphthalene; and the method is suitable for preparing 2,6-dimethylnaphthalene.

The invention discloses a method for preparing 2,6-dimethyl naphthalene by alkylation reaction of MgAPO-11 molecular sieve catalytic naphthalene. The method comprises the following steps of: I, activating an MgAPO-11 molecular sieve; and II, mixing naphthalene with an alkylation reagent and a solvent to prepare a feed solution, and carrying out alkylation reaction on the feed solution and the activated MgAPO-11 molecular sieve catalytic naphthalene to obtain the 2,6-dimethyl naphthalene. According to the method for preparing 2,6-dimethyl naphthalene by alkylation reaction of MgAPO-11 molecular sieve catalytic naphthalene, the used MgAPO-11 molecular sieve is synthesized by adopting a conventional electric heating method or a microwave heating method; the alkylation reaction of the MgAPO-11 molecular sieve catalytic naphthalene can be used for overcoming the defects that the homogeneous catalysts including anhydrous AlCl3 and the like are difficult to separate from the product, severe in device corrosion and severe in environment pollution, so that the reaction activity and 2,6-DMN (Dimethylnitrosamine) selectivity are higher, the 2,6-/2,7-DMN ratio and anti-carbon deposition capacity are higher. Moreover, the reaction products and the catalysts are easy to separate. Besides, the method is simple to operate and convenient for large-scale production.

The invention relates to a preparation method of the 2,6-DMN, in particular to a preparation method of the 2,6-DMN by using a SAPO-11 molecular sieve. The preparation method mainly solves the problems that catalysts cannot be provided with high activity and 2,6-DMN selectivity simultaneously, and the catalysts are easy to inactivate. The method includes activating the SAPO-11 molecular sieve synthesized by microwave radiation and heating, mixing naphthalene and alkylation reagents with a solvent according to a molar ratio of 1:(2-4):(6-12), and performing alkylation reaction to obtain the 2,6-DMN at a temperature of 350 DEG C to 450 DEG C, at a pressure of 2 MPa to 5 MPa, at a quality airspeed of 0.5-2h-1 and at a carrier gas flow rate of 20-60 mL/min. According to the preparation method, the synthesized SAPO-11 molecular sieve can shorten the crystallization time greatly, and has high catalytic activity to the alkylation reaction of the naphthalene and high selectivity and good anti-carbon deposition competence to the 2,6-DMN.

The present invention belongs to the technical field of preparation of 2,6-dimethylnaphthalene, and particularly relates to a method for using CuSAPO-11 molecular sieve for preparation of 2,6-dimethylnaphthalene. The method solves the technical problems that high activity and high 2,6-DMN selectivity of a molecular sieve catalyst used in 2,6-dimethylnaphthalene preparation methods in the prior art are difficult to achieved at the same time and stability of the catalyst is poor. The catalyst used in the method is the silicon phosphate copper and aluminum molecular sieve CuSAPO-11, a copper salt is added into a process for synthesis of silicon phosphate aluminum molecular sieve SAPO-11 by use a hydrothermal synthetic method for further synthesis of the new type silicon phosphate copper and aluminum molecular sieve CuSAPO-11. The molecular sieve catalyst has suitable acid property, high specific surface area and large mesoporous pore size, so that the molecular sieve catalyst shows higher catalytic activity in the alkylation reaction of naphthalene, the molecular sieve catalyst has high 2,6-dimethylnaphthalene selectivity, and the ratio of 2,6-dimethylnaphthalene to 2,7-dimethylnaphthalene is high.

The invention discloses a method for catalytically preparing 2,6-dimethylnaphthalene through using magnetic ionic liquid. The method comprises the following steps of adding a mixed solution of methylnaphthalene and mesitylene in an ultrasonic reaction kettle provided with a stirrer, stirring to react for 35-45min in inert atmosphere, then adding a magnetic ionic liquid catalyst, reacting for 15-80min under the condition that temperature is 25-40 DEG C, the inert atmosphere exists, the stirring speed is 400-600r/min and the power of ultrasonic wave is 150-300W, and standing for 30min after completing reaction; a lower-layer catalyst can be directly recycled after subjected to magnetic filed separation; the mixed solution with an upper layer containing the 2,6-dimethylnaphthalene is furtherseparated and purified to obtain a 2,6-dimethylnaphthalene product and incompletely reacted raw materials. The method has the advantages of high catalytic activity, precise process, high reaction transformation rate, high 2,6-dimethylnaphthalene yield and the like.

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.

Process for the preparation of 2,6-dimethylnaphthalene comprising reacting with at least one aromatic hydrocarbon, in the presence of a zeolitic catalyst, a mixture of naphthalenes comprising a cut obtained by the fractionation of suitable petrochemical streams and subsequent treatment of the product thus obtained with a solid acid.

An object of the present invention is to provide a method for manufacturing 2,6-DMN, in which even when a mixture containing DMN isomers which includes 5 wt % or more of 2,7-DMN is used, a highly pure 2,6-DMN can be obtained. The method for manufacturing the highly pure 2,6-dimethylnaphthalene of the present invention comprises performing cooling crystallization of a mixture containing dimethylnaphthalenes which includes 2,6-dimethylnaphthalene, performing solid-liquid separation to obtain a solid component, and washing the solid component using a solvent, wherein the solid-liquid separation performed after the cooling crystallization includes press filtration. In the present invention, the pressure of the press filtration is preferably 10 kg/cm² or more, and according to the method of the present invention, even when a DMN mixture containing 5 wt % or more of 2,7-DMN is used as a feedstock, a highly pure 2,6-DMN can be manufactured, and in addition, even when a DMN mixture containing less than 25 wt % of 2,6-DMN is processed by cooling crystallization, a highly pure 2,6-DMN can be manufactured.

The invention relates to a method for synthesizing 2,6-dimethylnaphthalene with 2-methylnaphthalene and C10 aromatics by transferring an alkyl group, in particular to a method for synthesizing the 2,6-dimethylnaphthalene by transferring the alkyl group through a molecular sieve based catalyst by using the 2-methylnaphthalene and the C10 aromatics (which is an aromatics mixture using tetramethylbenzene as a main component, wherein the carbon atom number of the mixture is 10, and the mixture is a by-product of a petrifaction aromatics device) as raw materials. The method comprises the following steps of: blending the C10 aromatics a and the 2-methylnaphthalene b which are used as the raw materials into a mixture raw material by a weight ratio of a:b=1-5:1; keeping the reaction airspeed to be 0.1-3 h<-1> at a reaction temperature of 360-540 DEG C and a reaction pressure of 0-7.0 MPa; and realizing an alkyl group transfer reaction through the molecular sieve based catalyst to synthesize the 2,6-dimethylnaphthalene. In the invention, the catalyst has low inactivation speed and longer service life, and meanwhile, the reaction selectivity and the yield of the 2,6-dimethylnaphthalene can be effectively improved; in addition, the mixture of the C10 aromatics is used as the raw material, and thus the production process of the 2,6-dimethylnaphthalene is effectively simplified; and the utilization of the C10 aromatics resource which is a byproduct and has low carbon value is also beneficial to the reducing of the production cost.

A method for separating and purifying 2,6-dimethylnaphthalene, is provided in which 2,6-dimethylnaphthalene of high purity is obtained from a mixture of dimethylnaphthalene isomers with a high yield, by means of a combined process of column melt crystallization and sweating operation.

Provided is a method for the separation and purification of high-purity 2,6-dimethylnaphthalene from a reaction mixture of dimethylnaphthalenes by continuous crystallization. According to the method, shell-tubetype crystallization apparatuses are used to perform crystallization operations under a continuous flow of a reaction mixture of dimethylnaphthalenes, which is obtained from the synthesis of dimethylnaphthalenes using o-xylene and butadiene as starting materials. As a result, high-purity 2,6-dimethylnaphthalene is separated and purified in a high yield from the reaction mixture. In addition, the method is advantageous in terms of energy saving when compared to conventional separation methods and enables continuous separation and purification of 2,6-dimethylnaphthalene on an industrial scale. A system for implementing the method is further provided.