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

Novel catalysts and processes in accordance with the invention can accomplish high selectivity and conversion of naphthalenic compounds such as the conversion of methylnaphthalene (2-MN) or naphthalene to 2,6-dimethylnaphthalene (2,6-DMN). The catalysts are prepared by treating, for example, a ZSM-5-type material with iron in the presence of a halogen such as a fluoride. The resulting catalyst includes iron, as well as a significant portion of aluminum present in the ZSM-5-type starting material. Processes for using the catalysts also are disclosed.

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 present invention relates to a method for achieving high purity separation and refinement by controlling morphology and particle size of 2, 6-dimethylnaphthalene. And more particularly, the present invention relates to a method for obtaining high purity 2, 6-dimethylnaphthalene crystals, in which crystallization is carried out with a solvent that enables the crystals to form a square-plate shape. During the process, crystallization variables such as, agitation speed, cooling rate, solvent and composition ratio, are adjusted to control morphology and particle size of 2, 6-dimethylnaphthalene and to remove aggregation, thereby obtaining 2, 6-dimethylnaphthalene crystals of high purity.

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 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.

High-purity 2,6-dimethylnaphthalene is prepared by (1) subjecting a dimethylnaphthalene isomer mixture rich in 1,5-dimethylnaphthalene, high boiling point materials, unreacted 1,5-dimethyltetralin, and low boiling point materials, which are produced from a dehydrogenation reaction of 1,5-dimethyltetralin, to separation, using a distillation column; subjecting the dimethylnaphthalene mixture separated by the distillation column to liquid state isomerization in the presence of an isomerization catalyst; (3) a first crystallization (melt crystallization process) by cooling the product of liquid state isomerization with a refrigerant without a solvent to form crystals; and (4) a second crystallization (solution crystallization process) of mixing the crystals of the first crystallization step with a solvent to form crystals.

The ionic liquid catalyzed transalkylation process for preparing 2, 6-dimethyl naphthalene includes: mixing 2-methyl naphthalene or mixed methyl naphthalene, transalkylating agent and solvent in the molar ratio of 1 to (0.5-3) to 12; adding ionic liquid catalyst in 20-75 % of the total weight of the mixture liquid, and transalkylating reaction at the temperature of 20 deg.c to reflux temperature under the protection of inert gas for 2-11 hr to obtain 2, 6-dimethyl naphthalene. The present invention has simple technological path, reuse of the catalyst, no environmental pollution, greatly raised 2, 6-dimethyl naphthalene selectivity and lowered 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 are a novel microorganism and a method for purifying 2,6-naphthalene dicarboxylic acid with high purity using the microorganism. The microorganism is Pseudomonas sp. Strain HN-72 isolated from soil and has the ability to convert 2-formyl-6-naphthoic acid contained as an impurity in a crude naphthalene dicarboxylic acid, which is an oxidation product of 2,6-dimethylnaphthalene, to 2,6-naphthalene dicarboxylic acid. The Pseudomonas sp. strain HN-72 has excellent effects in producing high-purity 2,6-naphthalene dicarboxylic acid in high yield.