Method for synthesizing cinnamyl alcohol by selective hydrogenation of cinnamyl aldehyde

A cinnamaldehyde and selective technology, which is applied in chemical instruments and methods, preparation of organic compounds, preparation of hydroxyl compounds, etc., can solve problems such as increased hydrogen consumption or hydrogen circulation, increased cost of hydrogen use, and difficulty in improving selectivity , to achieve the effects of reduced hydrogen circulation, increased catalyst loading, and improved selectivity

Active Publication Date: 2020-05-08
NANJING POLYTECHNIC INSITUTE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, most of them are carried out in tank reactors or similar tank reactors such as trickle bed reactors. Due to the small amount of catalyst, the reaction efficiency is low. In order to obtain a higher conversion rate, a large amount of excess hydrogen is often used , higher reaction temperature, higher reaction pressure and other methods make it difficult to improve the selectivity of the reaction
The consumption of hydrogen or the amount of hydrogen circulation increases significantly, thereby greatly increasing the cost of using hydrogen; the reported values ​​of these documents are mostly: the conversion rate of cinnamaldehyde and the selectivity of cinnamyl alcohol are all less than 90% to 95% or cinnamyl alcohol Productive rate is less than 85%~90%, so not only there is long reaction time, but also relatively low productive rate, the actual result that is applied to industrial production is lower, so the preparation method of developing novel preparation cinnamyl alcohol has obvious social significance and economical significance
[0003] In order to overcome the deficiencies mentioned above and the poor heat transfer existing in common pipe diameter fixed-bed reactors, the invention provides a kind of selective hydrogenation of cinnamaldehyde to prepare cinnamyl alcohol The method uses a reactor with an inner diameter of ≤5mm, a reaction tube length of ≥20m, and a built-in solid catalyst with a particle size of ≤0.7mm. The catalyst uses a supported catalyst, and cinnamaldehyde and hydrogen are used as raw materials for one-step selective hydrogenation reaction. cinnamyl alcohol

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Preparation of 0.5% ruthenium-0.5% iron / alumina catalyst

[0024]Weigh about 1000g of 24-mesh to 30-mesh alumina that has been dried at 300°C for more than 4 hours and cooled to room temperature; first take 100.0g of alumina microspheres that have been dried at 300°C and cooled to room temperature, Soak for 1.0h to measure its water absorption rate to be 89.52%; accurately weigh 10.80g of reagent grade ruthenium trichloride hydrate, accurately weigh 12.00g of reagent grade anhydrous ferric chloride, add 716.0g of deionized water, and stir well to get impregnated Add solution A, add 800.0g of alumina microspheres that have been dried at 300°C and cooled to room temperature, and pour it into impregnating solution A for 1.0h. Stir continuously during the impregnating process to ensure that the impregnating solution is three times Al2O3 is evenly adsorbed; after impregnating the knot, move it into an oven, dry it at 100°C-120°C for 4h, cool it to room temperature, preactiva...

Embodiment 2

[0026] Performance testing of 0.5% ruthenium-0.5% iron / alumina catalyst

[0027] Measure 590mL of catalyst I with a measuring cylinder, put it into a reaction tube with an internal diameter of 5mm and a length of 30m, place it in a closed oil bath with automatic control and recirculating hot oil, feed nitrogen to slowly increase the pressure to 3.0MPa, Carry out a leak test on the reaction system, after passing the leak test, feed 5% H 2 -N 2 Mixed gas, gradually increase the temperature to 200°C, after constant temperature for 2 hours, switch to pure hydrogen and continue constant temperature for 2 hours, then cool down to 80°C, slowly increase the pressure to 3.0MPa with pure hydrogen, start the high pressure pump and inject 50% (m%) of cinnamon Aldehyde solution (solvent is isopropanol), adjust reaction temperature to be 100 ℃, H 2 / Cinnamaldehyde molar ratio is 15, cinnamaldehyde liquid hourly space velocity is 0.2h -1 After the conditions are stable, continue to react ...

Embodiment 3

[0029] Preparation of 2.0% ruthenium-2.0% iron / titania catalyst

[0030] Weigh about 1000g of titanium dioxide microspheres of 80 mesh to 100 mesh, dried at 300°C for more than 4 hours, and cool to room temperature; first take 100.0g of titanium dioxide microspheres dried at 300°C and cooled to room temperature, soak in desalted water for 2.0h as required Measure its water absorption rate to 65.38%; accurately weigh 33.33g of reagent grade ruthenium nitrate, accurately weigh 43.19g of reagent grade anhydrous ferric nitrate, add 326.9g of deionized water, stir well to obtain impregnation solution B, add accurately weighed Dry and cool to room temperature 500.0g of alumina microspheres, and pour it into the impregnating solution B for 2.0h. Stir continuously during the impregnating process to ensure that the impregnating solution is evenly absorbed by the titanium dioxide; In an oven, dry at 100°C to 120°C for 4 hours, cool to room temperature, preactivate with 0.5% (m%) sodium ...

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PUM

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Abstract

The invention discloses a method for synthesizing cinnamyl alcohol through selective hydrogenation of cinnamyl aldehyde. A tubular reactor is adopted, a small-particle solid special catalyst is arranged in the tubular reactor, the cinnamyl aldehyde and hydrogen are used as reaction raw materials, and the cinnamyl alcohol is synthesized by catalyzing the cinnamyl aldehyde to be selectively hydrogenated under the conditions that the reaction temperature is 50-120 DEG C and the reaction pressure of hydrogen is 0.5-5.0 MPa. Compared with the traditional kettle type, fixed bed and trickle bed reactors, the method provided by the method can obtain higher cinnamyl alcohol selectivity, cinnamyl alcohol yield and stability, and has better economic benefits.

Description

technical field [0001] The present application relates to the technical field of organic synthesis, in particular to a method for selectively hydrogenating cinnamaldehyde to synthesize cinnamyl alcohol. Background technique [0002] Cinnamyl alcohol is a white crystal with an aroma and sweetness similar to hyacinth and ointment. It is mainly used in cosmetics, essences and soap essences, and as an intermediate in organic synthesis to prepare cinnamyl chloride (medicine raw materials), such as for the preparation of apricot , peach, raspberry, plum and other flavor essences, cosmetic essences and soap essences have mild, long-lasting and comfortable aromas, elegant fragrances, and are also used as fixatives; often shared with phenylacetaldehyde, it is the preparation of narcissus essence , rose essence and other indispensable spices. Cinnamyl alcohol is a food spice that is allowed to be used in my country's "Hygienic Standards for the Use of Food Additives". It is mainly us...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C29/141C07C33/32B01J23/745B01J23/72B01J29/10B01J23/14B01J8/06
CPCC07C29/141B01J23/745B01J23/72B01J29/106B01J23/14B01J8/06B01J2229/186B01J2208/06C07C33/32
Inventor 吴永忠史为民魏昌水花小军
Owner NANJING POLYTECHNIC INSITUTE
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