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Preparation method of citral

A technology of citral and compound, applied in the field of preparation of citral, can solve the problems of difficult separation, low yield, large amount of catalyst, etc., and achieves high economy and selectivity, simple operation steps, high yield and high purity. Effect

Pending Publication Date: 2020-08-25
XINFA PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0019] The amount of catalyst used in the above synthesis route 2 is large, easy to hydrolyze, poor in stability, unfavorable for recovery and mechanical application; single-pass rearrangement reaction is not complete, separation is difficult, distillation loss is large, and the yield is low
The price of silanol, titanium tetrachloride or titanium tetrabutoxide, molybdenum dioxide diacetylacetonate used in the above-mentioned dehydrolinalool rearrangement method is high, and the cost is relatively high

Method used

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  • Preparation method of citral
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  • Preparation method of citral

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0085] Embodiment 1: the preparation of citral (Ⅰ)

[0086]

[0087] Under nitrogen protection, add 100 grams of tetrahydrofuran, 5.3 grams (0.22 moles) of magnesium powder, 1.8 grams of bromoacetaldehyde dimethyl acetal ( II 1 ), 0.05 gram of iodine, after stirring for 15 minutes at 30-40°C to initiate the reaction, 32.0 grams (a total of 0.2 moles) of bromoacetaldehyde dimethyl acetal (II 1 ) and 100 grams of tetrahydrofuran, drop it in 2 hours, then stir and react at 35-40°C for 1 hour to obtain III 1 without separation, cooled to 0-5°C, kept at 10-15°C, added dropwise 25.0 g (0.2 moles) of 6-methyl-5-hepten-2-one (Ⅳ), and added dropwise in 1 hour , after which the reaction was stirred at 10-15° C. for 2 hours. Distill under reduced pressure to recover tetrahydrofuran, add 100 grams of water and 100 grams of dichloromethane to the obtained residue, acidify with 50% acetic acid until the pH of the system is 4.0-4.5, stir at 30-35 ° C for 2 hours, and let it stand Layere...

Embodiment 2

[0091] Embodiment 2: the preparation of citral (Ⅰ)

[0092]

[0093] Under nitrogen protection, add 100 grams of tetrahydrofuran (THF), 5.3 grams (0.22 moles) of magnesium powder, 2.2 grams of bromoacetaldehyde diethyl acetal ( II 2 ), 0.02 gram of iodine, after stirring for 15 minutes at 30-40°C to initiate the reaction, 37.0 grams (a total of 0.2 moles) of bromoacetaldehyde diethyl acetal (Ⅱ) was added dropwise between 30-35°C 2 ) and 100 grams of tetrahydrofuran, drop it in 2 hours, then stir and react at 35-40°C for 1 hour to obtain III 2 . Cool to 0-5°C, keep the temperature at 10-15°C, add 25.0 g (0.2 moles) of 6-methyl-5-hepten-2-one (IV) dropwise, dropwise for 1 hour, then 10-15 The reaction was stirred at °C for 2 hours. Recover tetrahydrofuran by distillation under reduced pressure, add 100 g of water and 100 g of dichloromethane to the resulting residue, acidify with 50% aqueous phosphoric acid until the pH of the system is 4.0-4.5, stir at 20-25°C for 2 hour...

Embodiment 3

[0094] Embodiment 3: the preparation of citral (Ⅰ)

[0095]

[0096] Step (1): 2-triphenylphosphinoacetaldehyde dimethyl acetal bromide (Ⅲ 3 ) preparation

[0097] Under nitrogen protection, add 180 grams of acetonitrile, 33.8 grams (0.2 moles) of bromoacetaldehyde dimethyl acetal (II 1 ), 52.5 grams (0.2 moles) of triphenylphosphine, stirred and reacted at 60-65°C for 3 hours, cooled to 10-15°C, filtered, and obtained 85.3 grams of formula III after drying the filter cake 3 Compound, the yield is 98.9%, and the liquid phase purity is 99.5%.

[0098] Step (2): Preparation of Citral (I)

[0099] Under nitrogen protection, add 100 grams of N,N-dimethylformamide, 7.5 grams (0.11 moles) of solid sodium ethylate, 43.1 grams (0.1 moles) Embodiment 3 step (1) method gained formula III 3 Compound, cooled, kept between 10°C and 15°C, added dropwise 12.6 g (0.1 mol) of 6-methyl-5-hepten-2-one (Ⅳ), added dropwise for 1 hour, then stirred at 15-20°C React for 3 hours. Recover N,...

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Abstract

The invention provides a preparation method of citral. The method comprises the following steps: carrying out a Grignard reaction or substitution reaction on halogenated acetaldehyde acetal or halogenated paraldehyde and a reagent 1 (magnesium powder, triphenylphosphine or triphosphite) to obtain a corresponding Grignard reagent or Wittig reagent, reacting the obtained Grignard reagent or Wittig reagent with 6-methyl-5-hepten-2-one, and successively conducting acidifying and deprotection to obtain citral. The preparation method has the advantages of usage of cheap and accessible raw materials,simple operation steps, high reaction atom economy, high selectivity, high yield, high purity, low product cost, and suitability for green industrial production.

Description

technical field [0001] The invention relates to a preparation method of citral, which belongs to the technical field of fine chemical production. Background technique [0002] Citral, present in citrus oil, lemon oil, lemongrass oil, litsea cubeba oil, lime oil, verbena oil and other plant essential oils, the chemical name is 3,7-dimethyl-2,6-octadiene Aldehyde, English name is Citral, chemical formula is C 10 h 16 O, is an unsaturated chain aldehyde monoterpene mixture containing two double bonds. Citral has two double-bond cis-trans isomers: citral a (Geranial) and citral b (Neral). Conformation, with a strong lemon smell, boiling point 228-229 ° C, insoluble in water, miscible with ethanol and ether; citral b, also known as neral, is the Z-isomer of the 2-position double bond, boiling point 103°C. [0003] The structural formulas of the two isomers of citral are as follows: [0004] [0005] Citral has a wide range of uses, and can be used to prepare lemon essenc...

Claims

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Application Information

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IPC IPC(8): C07C47/21C07C45/54
CPCC07C45/54C07B2200/09C07C47/21
Inventor 戚聿新腾玉奇周立山钱余峰
Owner XINFA PHARMA
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