Synthesis method and application of long-chain methyl p-hydroxybenzoate

The technology of a chain paraben and a synthesis method is applied in the field of synthesis of long chain parabens, can solve problems such as being unsuitable for industrialized large-scale production, complicated product extraction steps, unfavorable environmental protection and the like, and achieves the solution of product separation difficulties, Conducive to environmental protection, saving resources and energy

Active Publication Date: 2014-10-29
李炳洁
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Evaporation of the reaction solution with water agent and alcohol under reduced pressure requires further extraction, washing, and recrystallization to separate the product. The prod

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] In the esterification reactor, add 2.76g (0.02mol) of p-hydroxybenzoic acid, 12.02g (0.06mol) of n-tridecyl alcohol, 0.266g (0.0014mol) of p-toluenesulfonic acid, and use a 20ml water separator to feed Add 25ml of benzene into the reaction vessel, heat to 180-190°C, reflux for 2 hours, and the esterification is complete. Cool the reaction solution to 25°C, add n-hexane that is 7 times the volume of the reaction solution while stirring, control the stirring speed at 25rmp, cool down to 19°C after the addition of n-hexane, stand for crystallization for 10h, and suction filter to obtain a filter cake and filtrate, the filter cake was dried to obtain 6.22g of pure product tridecylparaben, the yield was 97.0%, and the detection tridecylparaben purity was 98.3%.

[0043] Under the conditions of pressure -0.09MPa and temperature 50°C, n-hexane in the filtrate was evaporated under reduced pressure to obtain the remaining reaction solution, and p-hydroxybenzoic acid, alcohol, an...

Embodiment 2

[0045] Add 2.76g (0.02mol) of p-hydroxybenzoic acid, 20.04g (0.1mol) of n-tridecyl alcohol, and 0.065g (0.0002mol) of dodecylbenzenesulfonic acid into the esterification reactor in sequence, using a 20ml water separator , Add 25ml of cyclohexane into the esterification reactor, heat to 170-180°C, reflux for 3h, and the esterification is complete. Cool the reaction solution to 25°C, add n-hexane that is 4 times the volume of the reaction solution while stirring, control the stirring speed at 125rmp, cool down to 10°C after the addition of n-hexane, stand for crystallization for 1 hour, and suction filter to obtain a filter cake and filtrate, the filter cake was dried to obtain 6.26g of pure product tridecylparaben, the yield was 97.6%, and the detection tridecylparaben purity was 98.2%.

[0046] Under the conditions of pressure -0.09MPa and temperature 50°C, n-hexane in the filtrate was evaporated under reduced pressure to obtain the remaining reaction solution, and p-hydroxybe...

Embodiment 3

[0048] In the esterification reactor, add 2.76g (0.02mol) of p-hydroxybenzoic acid, 24.05g (0.12mol) of n-tridecyl alcohol, 0.58g (0.006mol) of sulfamic acid, and adopt a water separator of 20ml to Add 25ml of n-hexane into the reactor, heat to 150-160°C, reflux for 4 hours, and the esterification is complete. Cool the reaction solution to 25°C, add n-hexane that is 3 times the volume of the reaction solution while stirring, control the stirring speed at 10rmp, cool down to 25°C after the addition of n-hexane, stand for crystallization for 8 hours, and suction filter to obtain a filter cake and filtrate, the filter cake was dried to obtain 6.30g of pure product tridecylparaben, the yield was 98.2%, and the detection tridecylparaben purity was 98.4%.

[0049] Under the conditions of pressure -0.09MPa and temperature 50°C, n-hexane in the filtrate was evaporated under reduced pressure to obtain the remaining reaction solution, and p-hydroxybenzoic acid, alcohol, and water-carryi...

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Abstract

The invention provides a synthesis method of long-chain methyl p-hydroxybenzoate, which comprises the following steps: 1) adding p-hydroxybenzoic acid, alcohol and a catalyst into an esterification reactor, adding a water-carrying agent, and heating under reflux for dehydration; 2) cooling the reaction solution, adding n-hexane while stirring, cooling to -20-25 DEG C, standing for 0.5-10 hours, filtering to obtain a filter cake and a filtrate, and drying the filter cake to obtain white powdery long-chain methyl p-hydroxybenzoate; and 3) carrying out vacuum evaporation to remove the n-hexane in the filtrate to obtain a surplus reaction solution, adding the p-hydroxybenzoic acid, alcohol and water-carrying agent into the surplus reaction solution, and repeating the steps above, wherein the alcohol is normal decyl alcohol, normal undecyl alcohol, normal lauryl alcohol or normal tridecyl alcohol, and the water-carrying agent is benzene, cyclohexane or n-hexane. The n-hexane is directly added to precipitate the long-chain methyl p-hydroxybenzoate from the reaction solution without evaporating out excessive alcohol. The method has the advantages of separable product, reusable catalyst, alcohol, n-hexane and water-carrying agent, and no environment pollution.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and in particular relates to a synthesis method of long-chain parabens and an application thereof. Background technique [0002] Parabens, also known as parabens, are the most widely used and used preservatives in the world. Due to their low toxicity, non-irritation, wide antibacterial range, and easy to interact with other preservatives It has the advantages of compound use, stable chemical properties and wide pH value range. It is widely used in food, beverage, daily chemical industry, medicine, cosmetics, feed and various industrial anticorrosion. It is the mainstream in many developed countries. Food preservatives are also widely used in China, and the annual demand in the cosmetics industry alone reaches more than 50 tons. At present, parabens A, B, C, and butyl are mostly produced and used in China. In paraben esters, with the increase of the alkyl group constituting the ester, ...

Claims

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Application Information

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IPC IPC(8): C07C69/84C07C67/08C07C67/52A23K1/17A23K20/195
CPCA23K20/111C07C67/08C07C67/52C07C69/84
Inventor 李炳洁
Owner 李炳洁
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