Preparation method of benzyl alcohol
By using water as a solvent and lignin as a catalyst in the preparation of benzyl alcohol and combining organic alkali to maintain the alkaline environment of the reaction, the problems of low selectivity of benzyl alcohol preparation and unsafe reaction conditions in the prior art are solved, and high yield and safe reaction conditions are achieved.
Patent Information
- Application Number
- CN202411001508.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-25
- Publication Date
- 2025-03-25
AI Technical Summary
In the prior art, the preparation method of benzyl alcohol has problems such as low selectivity and unsafe reaction conditions, and the reaction time is long and the yield is low.
Water is used as a solvent and lignin is used as a catalyst. Under the condition that the temperature does not exceed 100°C, a certain proportion of organic alkali is added to maintain the alkaline environment of the reaction and conduct the reaction. The raw materials used in this process include melamine, ethylenediamine and triethylamine, and the reaction time is between 1 hour and 10 hours.
The yield of benzyl alcohol can reach up to 96.88%, and the reaction conditions are relatively safe and the reaction time is short, which solves the problems of low selectivity and unsafe reaction conditions in the prior art.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of chemical synthesis, and in particular to a method for preparing benzyl alcohol. Background Art
[0002] Benzyl alcohol is widely used in the production of industrial chemicals. It is used as a solvent for coatings, photographic developers, stabilizers for polyvinyl chloride, medicines, synthetic resin solvents, solvents for vitamin B injections, and preservatives for ointments or liquid medicines. It can be used as a drying agent for nylon yarns, fibers, and plastic films, a solvent for dyes, cellulose esters, and casein, and an intermediate for preparing benzyl esters or ethers. At the same time, it is widely used in pen making (ballpoint pen oil), paint solvents, etc. Benzyl alcohol is an extremely useful fixative and is an indispensable fragrance for the preparation of jasmine, moonflower, ylang ylang and other flavors. It is used to prepare soaps and daily cosmetic flavors. In recent years, its uses have become more and more extensive, and the market demand has also increased year by year. Research progress at home and abroad: H Arzoumanian et al. used bipyridine bis-2-(methylbenzyl) dioxymolybdenum or tungsten analogs to react at room temperature in Oxygen Atom Transfer in Dialkyldioxo-molybdenum or-tungsten Complexes. A Case of Dialkyldioxo-Alkylalkylideneoxohydroxometal Tautomerism 1991, 1, 55-56 to generate 2-methylbenzaldehyde and 2-methylbenzyl alcohol as the main products. The reaction conditions of this method are relatively mild, but the synthesis method of the reactants is relatively complicated. T Sivakumar et al. synthesized palladium intercalated surfactant exchanged fluorotetrasilicic mica (Pd-HDP-TSM) by ion exchange of surfactant and TSM, palladium intercalation and in-situ reduction in Selective Hydrogenation of 2-Methylbenzaldehyde Using Palladium Particles Generated in situ in Surfactant Exchanged Fluorotetrasilicic Mica 2001, 9, 860–861, and used the catalyst to catalyze the continuous hydrogenation of 2-methylbenzaldehyde to generate the intermediate product 2-methylbenzyl alcohol. This method requires the use of hydrogen during the reaction, which is relatively dangerous. Wu Xianchun et al., in A New Route for the Synthesis of Benzyl Alcohol and Benzyl Ether from Benzene and Formaldehyde over Shape-Selective Catalysts. Fine Chemicals, 2001, 18(02):114., used benzene and formaldehyde aqueous solution as raw materials, HZSM-5 as catalyst, and reacted at 200°C to synthesize benzyl alcohol. The conversion rate of benzene was 51.98%, and the selectivity of benzyl alcohol reached 53.10%. This method is green and environmentally friendly, has great potential, and is a method that can replace the hydrolysis of benzyl chloride. However, the yield is too low and the process needs to be further optimized. Li Shuan and Wang Xueming, in Research on the Preparation Process of High-yield Benzyl Alcohol. Journal of Jiangsu Ocean University (Humanities and Social Sciences Edition), 1997(1):48-50., used benzyl chloride and sodium hydroxide to hydrolyze under the catalysis of TEBA, sodium formate or sodium acetate to prepare benzyl alcohol. The reaction temperature was 100-104°C, the reaction time was 5-6 hours, and the yield of benzyl alcohol could reach more than 90%, and the highest could reach 96%. In Novel preparation of palladium nanoclusters using metalnitrates and their catalysis for oxidative acetoxylation of toluene in the presence of molecular oxygen. Langmuir, 2002, 18(5): 1849-1855., Ebitani K et al. used toluene and glacial acetic acid as raw materials, and in the presence of palladium acetate-supported carbon catalyst, vapor-phase oxidized toluene to synthesize benzyl acetate, and then obtained benzyl alcohol through hydrolysis reaction. However, the yield was low, and the cost of noble metal as catalyst was high, which was not suitable for industrial production. In contrast, the method used in the present invention adopts the more common reactant o-methylbenzyl bromide, the reaction conditions are relatively safe, the reaction time is short, and the yield is high. Therefore, the present invention is of great significance for the synthesis of o-methylbenzyl alcohol. Summary of the invention
[0003] The invention discloses a method for preparing o-methylbenzyl alcohol. The method maintains an alkaline reaction environment by adding a certain proportion of organic base, uses water as a solvent, uses lignin as a catalyst, is carried out at a temperature not exceeding 10-100° C., and the reaction time is between 1 hour and 10 hours. Under this optimized condition, the yield of ortho-substituted benzyl bromide converted into corresponding benzyl alcohol can reach up to 96.88%.
[0004] This invention solves the problems existing in the prior art and provides a method for preparing benzyl alcohol. The invention uses melamine, ethylenediamine and triethylamine as raw materials respectively, has low cost and simple operation, and can effectively solve the problem of low selectivity in the preparation of benzyl alcohol.
[0005] The invention aims to provide a method for preparing benzyl alcohol, comprising contacting a raw material containing o-methylbenzyl bromide and an amine with a catalyst, reacting at a certain temperature for a certain time, and obtaining a product containing benzyl alcohol.
[0006] The catalyst is lignin
[0007] The raw material containing amine is one of melamine, ethylenediamine and triethylamine.
[0008] The molar ratio of o-methylbenzyl bromide to melamine is (1-10):1, and the amount of water added is 0.1-10 ml.
[0009] Optionally, the molar ratio of o-methylbenzyl bromide to melamine is any value between 0-10.
[0010] The reaction time of o-methylbenzyl bromide and melamine is 1-10 hours, and the reaction temperature is 75°C.
[0011] Optionally, the reaction time of o-methylbenzyl bromide and melamine is any value between 1 and 10 hours.
[0012] The molar ratio of o-methylbenzyl bromide to ethylenediamine is (1-10):1, the molar ratio of lignin to o-methylbenzyl bromide is (0-5):1, and the volume of the added solvent water is 0-10 mL.
[0013] Optionally, the molar ratio of o-methylbenzyl bromide to ethylenediamine is any value in the range of 1-10:1, the molar ratio of lignin to o-methylbenzyl bromide is any value in the range of 0.01-5.00, and the volume of the added solvent water is any value in the range of 0.1-5.0.
[0014] The reaction temperature of o-methylbenzyl bromide and ethylenediamine is 10-100° C., and the reaction time is 1-10 hours.
[0015] Optionally, the reaction temperature of o-methylbenzyl bromide and ethylenediamine is 0-100° C., and the reaction time is 1-10 hours.
[0016] The molar ratio of the o-methylbenzyl bromide to triethylamine is (0.1-5.0):1, and the molar ratio of lignin to o-methylbenzyl bromide is (0.01-5.00):1.
[0017] Optionally, the molar ratio of o-methylbenzyl bromide to triethylamine is any value in the range of 0.01-5.00, and the molar ratio of lignin to o-methylbenzyl bromide is any value in the range of 0-5.00.
[0018] The reaction temperature of o-methylbenzyl bromide and triethylamine is 10-100° C., and the reaction time is 1-10 hours.
[0019] Optionally, the reaction temperature of o-methylbenzyl bromide and triethylamine is 10-100° C., and the reaction time is 1-10 hours. BRIEF DESCRIPTION OF THE DRAWINGS The above are only several embodiments of the present invention and are not intended to limit the present application in any form. It should be pointed out that any technician familiar with the profession in this technical field can make several improvements and changes without departing from the principles of the present invention, and these improvements and changes are also considered to be within the scope of protection of the present invention.
[0020] Figure 1 The NMR of the product 1 H NMR spectrum.
[0021] Figure 2 It is the GC-MS spectrum of the product of Example 1.
[0022] Figure 3 It is the GC-MS spectrum of the product of Example 2.
[0023] Figure 4 It is the GC-MS spectrum of the product of Example 3.
[0024] Figure 5 It is the GC-MS spectrum of the product of Example 4.
[0025] Figure 6 This is the GC-MS spectrum of the product of Example 5.
[0026] Figure 7 This is the GC-MS spectrum of the product of Example 6.
[0027] Figure 8 This is the GC-MS spectrum of the product of Example 7.
[0028] Fig. 9 This is the GC-MS spectrum of the product of Example 8. DETAILED DESCRIPTION
[0029] The present invention will be further described in the following examples, but the present invention is not limited thereto.
[0030] Example 1
[0031] At room temperature, o-methylbenzyl bromide (107.9 mg, 0.583 mmol), melamine (18.8 mg, 0.149 mmol), and water (1 ml) were added to a flask equipped with a magnetic stirrer, and the temperature was raised to 75°C. The reaction temperature was maintained at 75°C for 2 hours and 30 minutes, and the reaction was carried out under closed condensation reflux to prevent the volatile raw materials from volatilizing. After the reaction was completed, the reaction was concentrated by rotary evaporation, dried to remove water, and the product was detected by GC-MS. The reaction results showed that the yield of benzyl alcohol was 68.72%.
[0032] Example 2
[0033] At room temperature, o-methylbenzyl bromide (77.3 mg, 0.42 mmol), melamine (52.8 mg, 0.42 mmol), and water (0.5 ml) were added to a flask equipped with a magnetic stirrer, and the temperature was raised to 75°C. The reaction temperature was maintained at 75°C for 2 hours and 45 minutes. The reaction was carried out under closed condensation reflux to prevent the volatile raw materials from volatilizing. After the reaction was completed, the reaction was concentrated by rotary evaporation, dried to remove water, and the product was detected by GC-MS. The reaction results showed that the yield of benzyl alcohol was 59.67%.
[0034] Example 3
[0035] The reaction conditions were the same as those in Example 1, except that the reaction time was 5 hours. The reaction results showed that the yield of benzyl alcohol was 96.88%.
[0036] Example 4
[0037] At room temperature, add o-methylbenzyl bromide (146.4 mg, 0.79 mmol), ethylenediamine (15.8 mg, 0.263 mmol), water (1 ml), 10.6 mg of lignin to a flask equipped with magnetic stirring, heat to 75°C, maintain the reaction temperature at 75°C, react for 2 hours and 30 minutes, and perform under closed condensation reflux to prevent volatile raw materials from volatilizing. After the reaction is completed, filter, concentrate the liquid, dissolve in methanol, precipitate by rotary evaporation, and detect the product by GC-MS. The reaction results show that the yield of benzyl alcohol is 55.95%.
[0038] Example 5
[0039] At room temperature, add o-methylbenzyl bromide (66.1 mg, 0.357 mmol), ethylenediamine (10.0 mg, 0.166 mmol), water (0.5 ml), 7.1 mg of lignin to a flask equipped with magnetic stirring, raise the temperature to 75°C, maintain the reaction temperature at 75°C, and react for 2 hours and 45 minutes under closed condensation reflux to prevent the volatile raw materials from volatilizing. After the reaction is completed, filter, concentrate the liquid, dissolve in methanol, precipitate by rotary evaporation, and detect the product by GC-MS. The yield of benzyl alcohol is 83.99%.
[0040] Example 6
[0041] The reaction conditions were the same as those in Example 5, except that the reaction time was 2 hours and the amount of water added was 1 ml. Reaction results: the yield of benzyl alcohol was 90.12%.
[0042] Example 7
[0043] At room temperature, add o-methylbenzyl bromide (138.7 mg, 0.75 mmol), triethylamine (19.6 mg, 0.194 mmol), water (1.0 ml), 0 mg lignin to a flask equipped with magnetic stirring, heat to 75 ° C, maintain the reaction temperature at 75 ° C, react for 5 hours, and conduct under closed condensation reflux to prevent volatile raw materials from volatilizing. After the reaction is completed, filter, concentrate the liquid, dissolve in methanol, precipitate by rotary evaporation, and the product is detected by GC-MS. The reaction results show that the yield of benzyl alcohol is 85.77%.
[0044] Example 8
[0045] At room temperature, add o-methylbenzyl bromide to a flask equipped with a magnetic stirrer. (0.3573mg, 2.089mmol), triethylamine (59.9mg, 0.592mmol), water (1.0ml), lignin 13.5mg, heated to 75℃, maintained at 75℃, reaction time 3 hours, closed condensation reflux to prevent volatile raw materials from volatilizing. After the reaction, filter, concentrate the liquid, dissolve in methanol, precipitate by rotary evaporation, and the product is detected by GC-MS. The reaction results show that the yield of benzyl alcohol is 79.37%.
Claims
1. A method for preparing benzyl alcohol, characterized in that The raw material containing o-methylbenzyl bromide and amine is contacted with a catalyst, and reacted at a certain temperature for a certain time to obtain a product containing benzyl alcohol.
2. The preparation method according to claim 1, characterized in that The catalyst in step (1) is lignin.
3. The preparation method according to claim 1, characterized in that The amine-containing raw material in step (1) is one of melamine, ethylenediamine and triethylamine.
4. The preparation method according to claim 1, characterized in that The molar ratio of o-methylbenzyl bromide to melamine in step (1) is (1-8):1, and the amount of water added is 0.5-8 ml.
5. The preparation method according to claim 1, characterized in that The reaction time of o-methylbenzyl bromide and melamine in step (1) is 1-10 hours, and the reaction temperature is 20-100°C.
6. The preparation method according to claim 1, characterized in that In step (1), the molar ratio of o-methylbenzyl bromide to ethylenediamine is (1-10):1, the molar ratio of lignin to o-methylbenzyl bromide is (0.05-5):1, and the volume of the added solvent water is 0.5-10 mL.
7. The preparation method according to claim 1, characterized in that The reaction temperature of the o-methylbenzyl bromide and ethylenediamine in step (1) is 10-100° C., and the reaction time is 1-10 hours.
8. The preparation method according to claim 1, characterized in that In step (1), the molar ratio of o-methylbenzyl bromide to triethylamine is (0.1-5.0):1, and the molar ratio of lignin to o-methylbenzyl bromide is (0-5.0):
1.
9. The preparation method according to claim 1, characterized in that The reaction temperature of the o-methylbenzyl bromide and triethylamine in step (1) is 10-100° C., and the reaction time is 1-10 hours.