Efficient condensation process in perfume synthesis
By reacting epoxide with a methylating agent under acid catalysis, combined with alkaline adjustment and vacuum distillation, the problems of cumbersome steps and low yield in the preparation of phenylacetaldehyde dimethyl acetal in the prior art have been solved, and efficient and low-cost synthesis of phenylacetaldehyde dimethyl acetal has been achieved.
Patent Information
- Application Number
- CN202511794389.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-02
- Publication Date
- 2026-01-23
AI Technical Summary
Existing methods for preparing phenylacetaldehyde dimethyl acetal have problems such as complicated steps, low yield and high cost. In particular, the intermediate phenylacetaldehyde is prone to polymerization during the separation and purification process, resulting in a yield of less than 70%.
The reaction of phenylene oxide with a methylating agent under acid catalysis, followed by pH adjustment with an alkaline solution and solvent removal under reduced pressure, and finally distillation, yields high-purity phenylacetaldehyde dimethyl acetal.
It achieves a simple process, low cost, low energy consumption, a yield of over 93%, and a product purity of 98.5%, making it suitable for industrial applications.
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of perfume technology, in particular to a high-efficiency condensation process in the synthesis of a perfume. BACKGROUND
[0002] Phenylacetaldehyde dimethyl acetal, as an important perfume ingredient, has a soft floral fragrance and is widely used in the fields of perfume, daily chemical essence and food additive. At present, the preparation method of phenylacetaldehyde dimethyl acetal mainly includes two steps:
[0003] 1. Preparation of phenylacetaldehyde
[0004] Oxidation method: phenylacetaldehyde is prepared by oxidizing phenylethanol with oxygen in air under the catalysis of metal oxide (chromium, etc.), which is easy to cause over-oxidation, has low yield and causes serious pollution.
[0005] Catalytic isomerization: phenylacetaldehyde is prepared by isomerization of epoxystyrene in the presence of a catalyst (acid, molecular sieve, silica gel, activated carbon, etc.), which has high cost and low yield due to the easy polymerization of the product under acidic conditions.
[0006] Methyl phenylalkyl ether is prepared by the olefinic reaction of methanol with phenylacetylene in a two-phase catalytic system, and then phenylacetaldehyde is directly hydrolyzed.
[0007] 2. Preparation of phenylacetaldehyde dimethyl acetal
[0008] Phenylacetaldehyde is used as a raw material, and is reacted with methanol to obtain phenylacetaldehyde dimethyl acetal.
[0009] In the current industrialized process of phenylacetaldehyde dimethyl acetal, the intermediate phenylacetaldehyde needs to be separated and purified, is easy to polymerize, has low yield, generally has a yield of less than 70%, and has high cost, so it is urgent to develop a preparation process of phenylacetaldehyde dimethyl acetal with short steps and high yield. SUMMARY
[0010] The purpose of the present application is to provide a high-efficiency condensation process in the synthesis of a perfume with short steps and high yield.
[0011] To achieve the above purpose, the present application provides the following technical scheme:
[0012] The present application provides a high-efficiency condensation process in the synthesis of a perfume, which includes the following steps:
[0013] (1) adding epoxystyrene into a methylation reagent and reacting under the catalysis of an acid;
[0014] (2) after the reaction is completed, adding an alkaline solution to adjust the pH to 7-8, standing to separate the layers, and taking the organic phase;
[0015] (3) the organic phase is first reduced in pressure and evaporated at 50-70°C, then subjected to rectification, to obtain benzene acetaldehyde dimethyl acetal.
[0016] In the above technical solution, the purity of the benzene acetaldehyde dimethyl acetal prepared is ≥98.5%.
[0017] Further, the methylating agent in step (1) is one of dimethyl sulfate, trimethyl orthoformate and dimethyl carbonate.
[0018] Further, the methylating agent in step (1) is trimethyl orthoformate.
[0019] Further, the amount of the methylating agent in step (1) is 1.2-10.0 eq relative to the epoxystyrene.
[0020] Further, the amount of the methylating agent is 1.2-1.5 eq relative to the epoxystyrene.
[0021] Further, the acid reagent used in the acid catalysis in step (1) is one of concentrated sulfuric acid, concentrated phosphoric acid, hydrochloric acid, p-toluenesulfonic acid and methane sulfonic acid.
[0022] Further, the acid reagent used in the acid catalysis in step (1) is methane sulfonic acid.
[0023] Further, the amount of the acid used in the acid catalysis in step (1) is 0.01-1.0 eq relative to the epoxystyrene.
[0024] Further, the amount of the acid is 0.02-0.03 eq relative to the epoxystyrene.
[0025] Further, the reaction temperature of the acid catalysis in step (1) is 20-120°C.
[0026] Further, the reaction temperature of the acid catalysis in step (1) is 40-80°C.
[0027] Further, the basic solution in step (2) is an organic amine solution or an inorganic alkali aqueous solution.
[0028] Further, the organic amine is triethylamine, diethylamine, trimethylamine, dimethylamine, propylamine, diisopropyl ethylamine, DBU, etc.
[0029] Further, the inorganic alkali is sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium bicarbonate, potassium bicarbonate, etc.
[0030] Further, the basic solution is a sodium bicarbonate aqueous solution.
[0031] Compared with the prior art, the synthesis of the perfume, benzaldehyde dimethyl acetal, provided by the application has the advantages of high condensation efficiency, low cost, simple process, low energy consumption, high yield, good product quality, high purity, and wide industrial application prospect. DETAILED DESCRIPTION
[0032] The technical solutions of the application are further described below in combination with specific examples. It should be understood that the following examples are only illustrative and explanatory of the application, and should not be interpreted as limiting the scope of protection of the application. Any technology achieved based on the above description of the application is covered within the scope of protection intended by the application.
[0033] Note: eq is the molar equivalent.
[0034] Example 1
[0035] In a 500 mL flask, trimethyl orthoformate (106 g, 1.2 eq), dioxane (100 g, 1.0 eq) were added, stirred at 20-30℃ for 30 min, methane sulfonic acid (1.6 g, 0.02 eq) was added, the temperature was raised to 50-60℃, and stirred for 5 hours. The reaction was completed, sodium bicarbonate aqueous solution (5%) was added dropwise to adjust the pH to 7-8, stirred for 30 min, and the pH was constant. The layers were separated after standing, the organic phase was first evaporated at 60℃, then rectified, and the fraction was collected to obtain benzaldehyde dimethyl acetal (133.1 g, 99.2%), with a yield of 96.2%.
[0036] Example 2
[0037] In a 500 mL flask, trimethyl orthoformate (123.6 g, 1.4 eq), dioxane (100 g, 1.0 eq) were added, stirred at 20-30℃ for 30 min, methane sulfonic acid (2.4 g, 0.03 eq) was added, the temperature was raised to 50-60℃, and stirred for 5 hours. The reaction was completed, sodium bicarbonate aqueous solution (5%) was added dropwise to adjust the pH to 7-8, stirred for 30 min, and the pH was constant. The layers were separated after standing, the organic phase was first evaporated at 50℃, then rectified, and the fraction was collected to obtain benzaldehyde dimethyl acetal (130.7 g, 99.5%), with a yield of 94.5%.
[0038] Example 3
[0039] In a 500 mL flask, trimethyl orthoformate (132 g, 1.5 eq), dioxane (100 g, 1.0 eq) were added, stirred at 20-30 °C for 30 min, methane sulfonic acid (1.6 g, 0.02 eq) was added, the temperature was raised to 50-60 °C, stirred for 5 hours, the reaction was completed, sodium bicarbonate aqueous solution (5%) was added dropwise to adjust the pH to 7-8, stirred for 30 min, rechecked, unchanged, stood and separated, the organic phase was first evaporated at 68 °C, then rectified, the fraction was collected, and benzene acetaldehyde dimethyl acetal (132.6 g, 98.9%) was obtained, the yield was 95.8%.
[0040] Although the specific embodiments of the present application have been described above, it should be understood by those skilled in the art that the specific examples described are illustrative only and not limiting to the scope of the present application, and modifications and variations made in accordance with the spirit of the present application should be covered within the scope of the claims of the present application.
Claims
1. A high efficiency condensation process in the synthesis of fragrances, characterized in that: The method comprises the following steps: (1) adding epoxystyrene into a methylating agent and reacting under acid catalysis; (2) after the reaction is completed, adding a basic solution to adjust the pH to 7-8, standing to separate layers, and taking the organic phase; (3) evaporating the solvent from the organic phase at 50-70 ℃ under reduced pressure, and then performing rectification to obtain benzene acetaldehyde dimethyl acetal.
2. The process as claimed in claim 1, wherein the process is characterized by: The methylating agent in step (1) is one of dimethyl sulfate, trimethyl orthoformate and dimethyl carbonate.
3. The process as claimed in claim 1, wherein the process is characterized by: The amount of the methylating agent in step (1) is 1.2-10.0 eq relative to epoxystyrene.
4. The process as claimed in claim 1, wherein the process is characterized by: The acid reagent used in the acid catalysis in step (1) is one of concentrated sulfuric acid, concentrated phosphoric acid, hydrochloric acid, p-toluenesulfonic acid and methane sulfonic acid.
5. The process as claimed in claim 1, wherein the process is characterized by: The amount of the acid in the acid catalysis in step (1) is 0.01-1.0 eq relative to epoxystyrene.
6. The process as claimed in claim 1, wherein the process is characterized by: The reaction temperature of the acid catalysis in step (1) is 20-120 ℃.
7. The process as claimed in claim 1, wherein the process is characterized by: The basic solution in step (2) is an organic amine solution or an inorganic alkali aqueous solution.