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Rhodium catalyst for preparing D,L-menthol and preparation method of D,L-menthol

A rhodium catalyst and menthol technology, which is applied in the field of d,l-menthol preparation, can solve the problems of production environmental protection and unfavorable cost, and achieve the effect of mild catalyst use process conditions, simple preparation process and good stability

Active Publication Date: 2020-11-03
SHANGHAI INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, high temperature and high pressure will produce some hydrocarbons that are no longer beneficial, and the use of solvents and two-step rules is not conducive to production environmental protection and cost

Method used

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  • Rhodium catalyst for preparing D,L-menthol and preparation method of D,L-menthol
  • Rhodium catalyst for preparing D,L-menthol and preparation method of D,L-menthol
  • Rhodium catalyst for preparing D,L-menthol and preparation method of D,L-menthol

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Experimental program
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Effect test

Embodiment 1

[0035] In a 250ml round bottom flask, add 15.35g rhodium trichloride trihydrate, 1.21g nickel dichloride hexahydrate and 0.63g zinc chloride, dissolve with 30ml distilled water, then add 93.4g γ-Al 2 o 3 ; Stir well, distill off the water under reduced pressure to obtain a powder; the powder is reduced in hydrogen at 250-300°C for 3-4 hours, and then the reduced product is washed with distilled water to completely remove Cl - After that, dry it again and dry it in vacuum to obtain the catalyst.

Embodiment 2

[0037] In a 250ml round bottom flask, add 20.46g rhodium trichloride trihydrate, 2.43g nickel dichloride hexahydrate and 1.25g zinc chloride, dissolve with 35ml distilled water, then add 90.8g γ-Al 2 o 3 ; Stir well, distill off the water under reduced pressure to obtain a powder; the powder is reduced in hydrogen at 250-300°C for 3-4 hours, and then the reduced product is washed with distilled water to completely remove Cl - After that, dry it again and dry it in vacuum to obtain the catalyst.

Embodiment 3

[0039]In a 250ml round bottom flask, add 25.58g rhodium trichloride trihydrate, 4.05g nickel dichloride hexahydrate and 2.08g zinc chloride, dissolve with 40ml distilled water, then add 88g γ-Al 2 o 3 ; Stir well, distill off the water under reduced pressure to obtain a powder; the powder is reduced in hydrogen at 250-300°C for 3-4 hours, and then the reduced product is washed with distilled water to completely remove Cl - After that, dry it again and dry it in vacuum to obtain the catalyst.

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Abstract

The invention relates to a rhodium catalyst for preparing D,L-menthol and a preparation method of D,L-menthol, wherein the rhodium catalyst is prepared by the following method: 1) adding rhodium salt,nickel salt and zinc salt into water to obtain a mixed saline solution; 2) soaking the carrier in a mixed saline solution, uniformly stirring, and carrying out reduced pressure distillation to removewater, thereby obtaining powder; and 3) reducing the powder in a hydrogen atmosphere, and washing and drying the powder to obtain the rhodium catalyst. The preparation method of the D,L-menthol comprises the following steps: S1) adding a rhodium catalyst and thymol into a hydrogenation kettle, and replacing air with hydrogen; and S2) heating the kettle, introducing hydrogen, carrying out a catalytic hydrogenation reaction, and then carrying out an isomerization reaction. Compared with the prior art, the method has the advantages that the self-made rhodium catalyst is used for catalyzing thymol hydrogenation to obtain isomers mainly containing d and lmenthol, the conversion rate of thymol can reach 99.9%, and the selectivity of generated d and lmenthol is high and is 65.0% to 70.0%; and the selectivity of D,L-isomenthol generation is low (6.0-8.0%).

Description

technical field [0001] The invention belongs to the technical field of d,l-menthol preparation, and relates to a gamma-Al compound used for preparing d,l-menthol 2 o 3 The preparation method of supported heterogeneous rhodium catalyst and d,l-menthol. Background technique [0002] d, l-menthol is mainly used to synthesize l-menthol, and l-menthol is mainly used in the fields of medicine, food additives and spices. Due to the rapid growth of the global economy, the demand for menthol is also increasing. In 2007, the global annual output has increased from 6,300 tons in 1992 to nearly 20,000 tons, of which synthetic menthol has also increased from 2,200 tons in 1992 to 6,300 tons. Natural menthol is extracted from plants, and the output is greatly affected by seasons and planting areas, resulting in very large price fluctuations. The output of naturally extracted menthol can no longer meet the growing industrial needs. The output of synthetic menthol is stable and the pric...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/89B01J37/02B01J37/18C07C35/12C07C29/19
CPCB01J23/8953B01J37/0201B01J37/18C07C29/19C07B2200/07C07C35/12Y02P20/584
Inventor 章平毅王朝阳毛海舫姚跃良刘吉波
Owner SHANGHAI INST OF TECH
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