CN115466234B - Preparation method of gamma-heptanolide - Google Patents

The invention relates to a preparation method of gamma-heptanolide, which belongs to the technical field of spice preparation and comprises the following steps: taking triethyl phosphorylacetate and furfural as raw materials to react under the action of an alkaline catalyst A to obtain a 2-furan ethyl acrylate intermediate; the 2-ethyl furan acrylate intermediate is subjected to hydrogenation cyclization under the action of a high-activity metal catalyst B, and the pressure and the temperature are controlled to obtain gamma-heptanolide; taking triethyl phosphorylacetate as a raw material, enabling the triethyl phosphorylacetate and furfural which is easily obtained from the raw material to perform a Hona-Wolz Walsh-Eymond reaction under an alkaline condition to synthesize a 2-furylacrylate intermediate, and then obtaining gamma-heptanolide through hydrogenation of the intermediate by taking high-activity metal as a catalyst; the invention has the advantages of low price of synthesized raw materials, higher product yield, high purity of products without isomers, simple reaction condition, simple process route and high industrial application value.

Preparation method of gamma-heptanolide

Technical Field

The invention belongs to the technical field of spice preparation, and particularly relates to a preparation method of gamma-heptanolide.

Background

Gamma-heptolactone, also known as propinqualide, is mainly used in food flavors, and can be added in small amounts to certain cosmetic flavors and perfumes to act as a "picture-in-the-eye" and is a food flavor prescribed in GB 2760-96 to be allowed to be used. The method is mainly used for preparing essence such as nuts, coconuts, fruits and the like and is used for preparing daily-use cosmetic essence and tobacco essence, so that efficient, simple and convenient synthesis of gamma-heptanolide has been widely paid attention.

The main synthesis method at present is as follows: peroxide is used as a free radical catalyst, acrylic acid and butanol are used as raw materials, and a free radical addition reaction is carried out under the condition of the catalyst to obtain gamma-heptanolactone.

Sun Qingling in 1995, journal of the world, proposed a method for synthesizing gamma-lactone from aldehyde: taking aldehyde as an initial raw material, carrying out heating condensation and decarbonation on the aldehyde and malonic acid in the presence of a pyridine (or triethylamine) catalyst to obtain an intermediate product olefine acid, and then carrying out intramolecular cyclization in the presence of an HY type molecular sieve to finally generate corresponding gamma-lactone, wherein the maximum product yield is 58.8%; but the method is complicated to operate.

In the prior art, fatty alcohol is used as a raw material to be subjected to bromination, grignard reaction to obtain fatty magnesium bromide, then the fatty magnesium bromide and furfural are subjected to Grignard reaction, gamma-keto acid is obtained through ring opening rearrangement, and gamma-lactone is obtained through hydrogenation and lactonization; the price of the furfural is low and the furfural is easy to obtain, and the method has a certain market prospect; but the process steps are more, which is unfavorable for industrial scale-up.

The patent Akira Y.preparation of gamma-alky1-gama-lactone Jpn Pat 55 133371,1980 reports a method for preparing gamma-lactone by cyclization reaction of 4 nonenoic acid in the presence of acid catalysts such as polyphosphoric acid, acid ion exchange resin, solid phosphoric acid and the like, wherein the yield is 52.3%; the method has short synthetic route and simple reaction condition, but has more byproducts, low product yield and quality and no environmental economy due to the strong oxidizing property of the concentrated sulfuric acid.

Therefore, it is necessary to provide a method for preparing gamma-heptanolactone efficiently, simply and conveniently.

Disclosure of Invention

In order to solve the technical problems mentioned in the background art, the invention provides a preparation method of gamma-heptanolide.

The aim of the invention can be achieved by the following technical scheme:

a method for preparing gamma-heptanolactone, comprising the steps of:

step a: taking triethyl phosphorylacetate and furfural as raw materials to react under the action of an alkaline catalyst A to obtain a 2-furan ethyl acrylate intermediate;

step b: the 2-ethyl furan acrylate intermediate is subjected to hydrogenation cyclization under the action of a high-activity metal catalyst B, and the pressure and the temperature are controlled to obtain gamma-heptanolide;

the reaction process is specifically as follows:

the specific operation method of the step a is as follows:

adding deionized water into a three-neck flask, slowly adding an alkaline catalyst A under stirring, adding triethyl phosphorylacetate after stirring and dissolving, controlling the temperature to be 35-40 ℃, dropwise adding furfural, controlling the dropwise adding temperature to be 35-40 ℃, carrying out heat preservation reaction for 12h after the dropwise adding is finished, standing for 1h, separating an organic layer, and carrying out aftertreatment to obtain the ethyl 2-furylacrylate.

Further, the alkaline catalyst A is one of potassium carbonate, sodium hydroxide, sodium carbonate and sodium methoxide, preferably potassium carbonate.

Further, the mole ratio of triethyl phosphorylacetate to basic catalyst a is 1:1-2, preferably 1:2.

further, the molar ratio of the furfural to the triethyl phosphorylacetate is 1-2:1, preferably 1.6:1.

the specific operation method of the step b is as follows:

adding 2-ethyl furan acrylate and a high-activity metal catalyst B into a hydrogenation kettle, replacing air with nitrogen, replacing nitrogen with hydrogen, controlling pressure and temperature, stirring and reacting for 5-15h, and filtering to remove the high-activity metal catalyst B to obtain gamma-heptanolide.

Further, the high activity metal catalyst B is one of ruthenium carbon, palladium carbon and raney nickel catalyst, preferably palladium carbon.

Further, the consumption of the high-activity metal catalyst B is 1-10 percent calculated by taking the mass of the 2-ethyl furan acrylate intermediate as 100 percent; preferably 10%.

Further, specific conditions of pressure and temperature are controlled as follows: the hydrogenation pressure is 0.5-1MPa, the reaction temperature is 100-150 ℃ and the reaction time is 5-15h. The preferential condition is that the hydrogenation pressure is 1MPa, the reaction temperature is 100 ℃, and the reaction time is 15h.

The invention has the beneficial effects that:

aiming at the defects of the prior art, the invention provides a preparation method of gamma-heptanolide, which takes triethyl phosphorylacetate as a raw material, enables the triethyl phosphorylacetate and furfural which is easily obtained from the raw material to carry out a Hour-Voltz-Eymond reaction under alkaline conditions to synthesize a 2-ethyl furan acrylate intermediate, and then takes high-activity metal as a catalyst to carry out hydrogenation to obtain gamma-heptanolide; the invention has the advantages of low price of synthesized raw materials, higher product yield, high purity of products without isomers, simple reaction condition, simple process route and high industrial application value.

Detailed Description

The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Example 1

Preparation of ethyl 2-furan acrylate:

240g of water is added into a 1000ml three-neck flask with a stirrer, a thermometer and a dropping funnel, stirring is started, 35g (0.875 mol) of sodium hydroxide is slowly added, stirring is carried out until the solution is dissolved, 100g (0.446 mol) of triethyl phosphorylacetate is added after stirring and dissolving, the temperature is controlled at 35 ℃, 69g (0.718 mol) of furfural is started to be dropped after the temperature of the kettle is stable, the dropping time is 3h, and the dropping temperature is controlled at 35 ℃. After dropping, the mixture was kept warm for 12 hours, the organic layer was separated after standing for 1 hour, the aqueous phase was extracted twice with 60g of methyl tert-butyl ether, the organic phases were combined, washed with saturated brine 2 times, methyl tert-butyl ether was distilled off at normal pressure, the furfural component at 70 to 90℃was collected under reduced pressure in a high vacuum, and the component fraction at 90 to 110℃was collected under reduced pressure using a fractionating column to obtain 64.59g (0.36 mol) of ethyl 2-furylacrylate with a yield of 80.17% and a purity of 92% (GC).

Example 2

Preparation of ethyl 2-furan acrylate:

240g of water is added into a 1000ml three-neck flask with a stirrer, a thermometer and a dropping funnel, stirring is started, 123g (0.891 mol) of potassium carbonate is slowly added, stirring is carried out until the solution is dissolved, 100g (0.446 mol) of triethyl phosphorylacetate is added after stirring and dissolving, the temperature is controlled at 40 ℃, 69g (0.718 mol) of furfural is started to be dropped after the temperature of the kettle is stable, the dropping time is 4 hours, and the dropping temperature is controlled at 40 ℃. After dropping, keeping the temperature for 12 hours, standing for 1 hour, separating an organic layer, extracting an aqueous phase with 60g of methyl tertiary butyl ether twice, merging the organic layers, washing with saturated brine for 2 times, steaming out the methyl tertiary butyl ether at normal pressure, collecting a furfural component at 70-90 ℃ under high vacuum and reducing pressure, and collecting a component fraction at 90-110 ℃ under reduced pressure by a fractionating column to obtain 70.25g (0.402 mol) of ethyl 2-furylacrylate, wherein the yield is 90.03 percent and the purity is 95 percent (GC) and the method is reserved for the next step.

Example 3

Preparation of ethyl 2-furan acrylate:

the amount of furfural as a reactant was changed to 45g (0.468 mol) as compared with example 2, and the other preparation and working-up steps were the same as in example 2, to obtain 42g (0.230 mol) of ethyl 2-furylacrylate, 51.56% yield and 91% purity (GC).

Example 4

Preparation of gamma-heptanolactone:

60g (GC: 95%0.361 mol) of the crude ethyl 2-furylacrylate of example 2, 6g of Raney nickel catalyst, nitrogen gas in place of air, hydrogen gas in place of nitrogen gas, charging hydrogen gas to 0.5MPa and heating to 100℃under stirring are charged into a 500ml autoclave. The reaction was stirred until the pressure did not drop, taking 15 hours. After cooling to room temperature, the catalyst was filtered off to give 30.45g (0.221 mol) of gamma-heptanolactone fraction with a purity of 93% (GC) in 64.41%. The crude product is decompressed and rectified to obtain 21.51g (0.167 mol) of gamma-heptanolactone finished product, the content is 99.25%, and the total reaction yield is 43.71%.

Example 5

Preparation of gamma-heptanolactone:

60g (GC: 95%0.361 mol) of the crude ethyl 2-furylacrylate of example 2, 6g of a palladium-carbon catalyst, nitrogen gas in place of air, hydrogen gas in place of nitrogen gas, charging hydrogen gas to 0.5MPa, and heating to 100℃under stirring were charged into a 500ml autoclave. The reaction was stirred until the pressure did not drop, taking 15 hours. Cooled to room temperature and the catalyst was filtered off. 35.12g (0.263 mol) of gamma-heptanolide fraction was collected by distillation under reduced pressure, and the purity was 96% (GC), yield 76.69%. The crude product is decompressed and rectified to obtain 28.35g (0.219 mol) of gamma-heptolactone finished product, the content is 99.2 percent, and the total reaction yield is 57.59 percent.

Example 6

Preparation of gamma-heptanolactone:

60g (GC: 95%0.361 mol) of the crude ethyl 2-furylacrylate of example 2, 6g of a palladium-carbon catalyst, nitrogen gas in place of air, hydrogen gas in place of nitrogen gas, charging hydrogen gas to 1MPa, and heating to 100℃under stirring were charged into a 500ml autoclave. The reaction was continued with stirring until the pressure was no longer reduced, for about 15 hours. Cooled to room temperature and the catalyst was filtered off. The filtrate was distilled under reduced pressure to collect 40.26g (0.30 mol) of gamma-heptanolide fraction with a purity of 95.56% (GC) and a yield of 87.51%. The crude product is decompressed and rectified to obtain 35.12g (0.272 mol) of gamma-heptolactone finished product, the content is 99.4%, and the total reaction yield is 71.48%.

In the description of the present specification, the descriptions of the terms "one embodiment," "example," "specific example," and the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. The foregoing is merely illustrative and explanatory of the invention, as various modifications and additions may be made to the particular embodiments described, or in a similar manner, by those skilled in the art, without departing from the scope of the invention or exceeding the scope of the invention as defined in the claims.