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Preparation method of 1, 4-cyclohexanedimethanol

A technology of cyclohexanedimethanol and cyclohexanedicarboxylic acid, which is applied in the field of continuous hydrogenation to prepare 1,4-cyclohexanedimethanol, which can solve the problem of reduced selectivity of target products, reduced reaction speed, and low concentration of reactants, etc. problems, achieve good industrial application prospects, fast hydrogenation rate, and high CHDM yield

Active Publication Date: 2022-05-06
浙江清和新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the limitation of mass transfer resistance, the reactant CHDA cannot quickly diffuse into the pores of the catalyst, resulting in a low concentration of reactants inside the catalyst, which significantly reduces the reaction rate; more importantly, if the CHDM produced by the reaction cannot quickly diffuse from the pores of the catalyst It is very easy to have side reactions such as decarboxylation and esterification, which greatly reduces the selectivity of the target product

Method used

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  • Preparation method of 1, 4-cyclohexanedimethanol
  • Preparation method of 1, 4-cyclohexanedimethanol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment A1

[0018] Embodiment A1: Weigh a certain amount of stannous chloride, palladium chloride and ruthenium chloride, dissolve them with hydrochloric acid, and put a certain amount of carbon nanotubes into the above solution for impregnation. Immerse for 24h, dry at 120°C for 4h, use NaBH 4 Reduction, wherein the supported amount of metal Ru was 5.0%, the supported amount of metal Pd was 0.5%, and the supported amount of Sn was 4.0%, and catalyst 1 was obtained.

Embodiment A2

[0019] Embodiment A2: The carrier is carbon nanofibers, and the others are the same as in Embodiment A1 to obtain catalyst 2.

Embodiment B1

[0033] The optimization of reaction process conditions was carried out in a fixed-bed reactor, and 20.0 g of catalyst 1 was filled in a reaction tube with an inner diameter of 13 mm. CHDA is dissolved in a high-pressure dissolution tank to obtain a 20 wt% CHDA aqueous solution, and the CHDA solution is pumped into the fixed bed by a high-temperature pump. Catalyst evaluation conditions: reaction temperature 230°C, reaction pressure 8.0MPa, CHDA feed mass space velocity 0.5h -1, the molar ratio of hydrogen to CHDA was 20.0. See Table 2 for the evaluation results. The corresponding reaction conditions were changed in Examples B2-B8, and the results are shown in Table 2.

[0034] Table 2

[0035]

[0036] From the comparison of Examples B1 to B3 in Table 2, it can be seen that the reaction effect of catalyst hydrogenation is better when the reaction temperature is 230°C. When the reaction temperature is as low as 210°C, some CHDA does not have time to participate in the rea...

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Abstract

The invention provides a preparation method of 1, 4-cyclohexanedimethanol, which comprises the following steps: 1, 4-cyclohexanedicarboxylic acid is subjected to hydrogenation reaction to prepare 1, 4-cyclohexanedimethanol, the reaction is carried out on a fixed bed reactor, 1, 4-cyclohexanedicarboxylic acid and water are heated and dissolved in a high-pressure reaction kettle, the solution is conveyed into the fixed bed reactor through a high-temperature pump, and the 1, 4-cyclohexanedimethanol is prepared through the high-temperature pump. Hydrogenation is performed under the action of a catalyst to obtain a product 1, 4-cyclohexanedimethanol; the active component of the catalyst is Ru, the auxiliaries are Pd and Sn, and the carrier is one of carbon nanotubes and carbon nanofibers. The conversion rate of the raw material 1, 4-cyclohexanedicarboxylic acid reaches 99.5% or above, and the yield of the product 1, 4-cyclohexanedimethanol can stably reach 98.5% or above. In addition, the service life of the catalyst is long, the one-way operation life of the catalyst is 2000h or above, and the method has a good industrial application prospect.

Description

technical field [0001] The invention belongs to the field of fine chemicals, and in particular relates to a method for continuously hydrogenating 1,4-cyclohexanedimethanol. Background technique [0002] 1,4-Cyclohexanedimethanol (CHDM) is an important raw material for polyester production. The polyethylene terephthalate (PET) resin modified by CHDM copolymerization has a slow crystallization rate, and at the same time It also has good processing and physical properties, especially the polyester modified by trans-CHDM has a high glass transition temperature and softening temperature, has good chemical resistance and environmental adaptability, and has a wide range of applications. At present, the main process for the industrial production of CHDM is to use dimethyl terephthalate as raw material. Firstly, the benzene ring is hydrogenated to generate dimethyl 1,4-cyclohexanedicarboxylate, and dimethyl 1,4-cyclohexanedicarboxylate The ester is further hydrogenated to produce CH...

Claims

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Application Information

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IPC IPC(8): C07C29/149C07C31/27B01J23/62B01J37/02B01J37/16
CPCC07C29/149B01J23/626B01J37/0201B01J37/16C07C31/276
Inventor 李显明徐铁勇洪俊杰王杰林桂海
Owner 浙江清和新材料科技有限公司