Method for preparing methyl heptenone

A technology of methyl heptenone and methyl, which is applied in the field of organic synthesis, can solve the problems of difficult product purification, many wastes, and complicated side reactions, and achieve the effect of high atom utilization rate, less wastes, and mild conditions

Pending Publication Date: 2020-02-28
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

It solves the shortcomings of the method used to synthesize methyl heptenone in the prior art, such as many wastes, complex side reactions, and difficult product purif...

Method used

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  • Method for preparing methyl heptenone
  • Method for preparing methyl heptenone
  • Method for preparing methyl heptenone

Examples

Experimental program
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Effect test

Embodiment 1

[0053] Add anhydrous lithium hydroxide (122.2mg, 5mmol) in the autoclave of 1000mL, after replacing three times with high-purity nitrogen, charge the nitrogen of 0.4MPa in the reaction kettle; In the glove box, [Rh(COD) 2 ]OTf (94.62mg, 0.2mmol), 3-methyl-2-butene-1-alcohol (87.0g, 1mol) and acetone (348.5g, 6mol) were mixed, and under nitrogen atmosphere, the above-mentioned mixture was pumped Add it into the autoclave, turn on the heating and stirring device of the reactor, raise the temperature to 80°C and keep it warm for 4 hours, the conversion rate of the raw material 3-methyl-2-buten-1-ol is >99% according to GC analysis, and the reaction is terminated .

[0054] After the reaction, the reaction liquid was lowered to room temperature, excess acetone and reaction water were removed by distillation under reduced pressure, and then further distillation under reduced pressure was performed to obtain a light yellow transparent liquid product, which was characterized by NMR a...

Embodiment 2-7

[0057] When carrying out embodiment 2-7, by rhodium catalyst by [Rh(COD) 2 ] OTf is replaced by other metal rhodium catalysts of an equivalent amount, and other conditions are constant.

Embodiment 8-15

[0059] When carrying out embodiment 8-13, metal rhodium catalyst is [Rh(COD) 2 ] OTf, the alkali is replaced by other types of alkali by lithium hydroxide, the consumption of acetone is 5-20eq. (the consumption of acetone is 20eq. -2-buten-1-alcohol addition is 0.25mol).

[0060] When carrying out embodiment 14-15, metallic rhodium catalyst is [Rh(COD) 2 ] OTf, the base is lithium hydroxide, the consumption of acetone is 4eq and 6eq, and other conditions remain unchanged.

[0061]

[0062] Table 2 embodiment 1-15 reaction result

[0063] Numbering Reaction time reaction pressure Conversion rates / % selectivity / % Example 1 4h 0.6MPa 99.63 97.29 Example 2 4h 0.6Mpa 98.79 96.11 Example 3 4h 0.6MPa 98.99 97.43 Example 4 4h 0.6MPa 97.33 95.13 Example 5 4h 0.6MPa 98.65 94.36 Example 6 4h 0.6MPa 95.99 95.78 Example 7 4h 0.6MPa 99.13 97.23 Example 8 6h 1.0MPa 98.56 98.13 Example ...

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Abstract

The invention discloses a method for preparing methyl heptanone. According to the method, 3-methyl-2-butene-1-ol and acetone undergoes a selective dehydrogenation coupling reaction under the action ofa rhodium catalyst, alkali and an optional assistant to generate methyl heptenone. Compared with the prior art, the method has the advantages that cheap and easily available 3-methyl-2-butene-1-ol and acetone are used as raw materials; the methyl heptenone with high additional value is prepared through a one-step reaction; and the method is high in atom utilization rate, low in generation of three wastes, mild in conditions and high in selectivity and yield.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a method for preparing methylheptenone through selective dehydrogenation coupling reaction of 3-methyl-2-buten-1-ol and acetone. Background technique [0002] Methylheptenone, the chemical name is 6-methyl-5-hepten-2-one, and the molecular formula is C 8 h 14 O, colorless or light yellow liquid, with lemongrass, isobutyl acetate and fresh fruit aroma, is a food flavor allowed by the national standard, and can be used to prepare banana, pear and berry flavors; in addition, methyl heptenone is also A very important synthetic intermediate that can be used in the synthesis of spices such as linalool, citral, and pseudoionone, which can be further used to prepare vitamin A, vitamin E, vitamin K1, and various spices and essences. The market demand for methyl heptenone is strong at present. With the deepening of people's application and development, its application range w...

Claims

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Application Information

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IPC IPC(8): C07C45/68C07C45/74C07C49/203
CPCC07C45/68C07C45/74C07C49/203
Inventor 沈稳黄文学于斌成谢硕张永振黎源
Owner WANHUA CHEM GRP CO LTD
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