Catalyst for synthesizing linalyl acetate, preparation method and application

Abstract

The invention relates to the technical field of chemical catalysts, in particular to a catalyst for synthesizing linalyl acetate, a preparation method and application, the catalyst comprises a Ti-doped mesoporous molecular sieve SBA-15 skeleton, and heteropoly acid is loaded in the Ti-doped mesoporous molecular sieve SBA-15 skeleton. According to the catalyst, Ti is introduced into an SBA-15 molecular sieve to form a Ti-O-Si structure, and moderate and strong Lewis acid sites are generated in a framework; then, by utilizing the huge specific surface area and uniform pore structure of the mesoporous molecular sieve SBA-15, a smooth diffusion path is provided for linalool and acetic anhydride molecules while a dispersion space is provided for heteropolyacid, so that the internal diffusion limitation is effectively reduced, the reaction efficiency is improved, and the side reaction is reduced; and finally, heteropolyacid with extremely strong Bronsted acidity is loaded and cooperates with Lewis acidic sites, so that the efficiency of catalytic esterification reaction is improved, and the problems that an existing catalyst for synthesizing linalyl acetate is low in catalytic efficiency, high in cost, easy to corrode equipment, easy to pollute the environment, unrecyclable and poor in safety are solved.

Description

Technical Field

[0001] This invention relates to the field of chemical catalyst technology, specifically to a catalyst for the synthesis of linalyl acetate, its preparation method, and its application. Background Technology

[0002] Linaloyl acetate is an important monomeric fragrance ingredient. Due to its unique aroma characteristics, it is an indispensable component in many fragrance formulations and a common fragrance-enhancing ingredient in daily cosmetics, perfumes, soaps, shampoos, and shower gels. For example, linaloyl acetate is often used as a base fragrance in the formulation of bergamot, lavender, bitter orange blossom, orange leaf, jasmine, and mixed lavender essential oils, establishing the overall aroma framework. Furthermore, in lilac, osmanthus, linden blossom, and oriental fragrances, it is often used as a top note, playing a harmonizing and modifying role in the aroma. With the continuous expansion of the fragrance and flavor market and the increasing demands of consumers for aroma quality, the demand for linaloyl acetate is also growing. Therefore, developing efficient, environmentally friendly, and economical methods for synthesizing linaloyl acetate is of great significance for meeting market demand and promoting the development of the fragrance and flavor industry.

[0003] Currently, in the fragrance industry, the synthesis of linalyl acetate mainly employs the direct acetylation reaction of linalool and acetic anhydride in the presence of phosphoric acid. This method is based on the nucleophilic substitution reaction between the hydroxyl group in linalool and the acetyl group in acetic anhydride under the catalysis of phosphoric acid, producing linalyl acetate and acetic acid. This method has been applied to a certain extent in long-term production practice and possesses a certain degree of maturity and stability. However, with the continuous growth of market demand and increasingly stringent environmental requirements, some technical problems with this method have gradually become prominent, severely restricting the development of linalyl acetate production. First, due to the long reaction time catalyzed by phosphoric acid, the decomposition and isomerization of linalool increase significantly, posing great difficulties for product purification, resulting in low yield and high cost. Second, in existing synthesis methods, the amount of phosphoric acid catalyst used is large, and since phosphoric acid is not recyclable, it not only increases the cost of raw materials but also wastes resources, resulting in poor economic efficiency. Simultaneously, during the reaction, phosphoric acid is corrosive to the reaction equipment, leading to a shortened equipment lifespan, and the post-processing is complex and causes serious environmental pollution.

[0004] Therefore, there is an urgent need to develop a new type of catalyst to solve the problems of catalysts used in traditional processes, thereby promoting the development of linalyl acetate production and meeting market demand for linalyl acetate. Summary of the Invention

[0005] To address the problems of low catalytic efficiency, high cost, easy corrosion of equipment, easy environmental pollution, non-recyclability, and poor safety of catalysts used in the synthesis of linalyl acetate in existing technologies, this invention provides a catalyst, preparation method, and application for the synthesis of linalyl acetate.

[0006] To achieve the above objectives, the present invention employs the following technical solution: The present invention provides a catalyst for the synthesis of linalyl acetate, comprising a Ti-doped mesoporous molecular sieve SBA-15 framework, wherein the Ti-doped mesoporous molecular sieve SBA-15 framework is loaded with heteropoly acids.

[0007] Optionally, the heteropolyacid is one or more of phosphotungstic acid, phosphomolybdic acid, and silicotungstic acid.

[0008] Optionally, in the Ti-doped mesoporous molecular sieve SBA-15 framework, the molar ratio of silicon atoms to titanium atoms is (10-30):1.

[0009] The present invention also provides a method for preparing a catalyst for the synthesis of linalyl acetate as described above, comprising: The triblock copolymer P123 was dissolved in a first hydrochloric acid solution to obtain a first mixture; Tetrabutyl orthosilicate and tetrabutyl titanate are dissolved in a second hydrochloric acid solution to obtain a second mixture; The second mixture is added to the first mixture to obtain a mixed reaction solution; The mixed reaction solution was subjected to crystallization, cooling, filtration, washing, drying and calcination in sequence to obtain the Ti-doped mesoporous molecular sieve SBA-15 framework. Ti-doped mesoporous molecular sieve SBA-15 framework was impregnated in a heteropoly acid solution, filtered, dried, and calcined a second time to obtain a catalyst for the synthesis of linalyl acetate.

[0010] Optionally, the first hydrochloric acid solution has a concentration of 1.75-1.8 mol / L.

[0011] Optionally, the molar ratio of tetraethyl orthosilicate to tetrabutyl titanate is (10-30):1; and the second hydrochloric acid solution has a concentration of 1.8-2.3 mol / L.

[0012] Optionally, in the mixed reaction solution, the total molar amount of tetrabutyl orthosilicate and tetrabutyl titanate to the molar ratio of triblock copolymer P123, hydrochloric acid and water is (0.95-1):(0.016-0.017):(5.74-5.89):(175.4-175.7).

[0013] Optionally, the crystallization treatment temperature is 100-120℃ and the crystallization time is 24-36h; the first calcination temperature is 500-600℃ and the first calcination time is 5-6h.

[0014] Optionally, in the heteropolyacid solution, the mass ratio of heteropolyacid to Ti-doped mesoporous molecular sieve SBA-15 framework is 10%-25%, and the mass ratio of Ti-doped mesoporous molecular sieve SBA-15 framework to water is 1:(15-20); the secondary calcination temperature is 150-200℃, and the secondary calcination time is 2-4h.

[0015] The applications of the above-mentioned catalysts used in the synthesis of linalyl acetate in the preparation of linalyl acetate include: Linalool and acetic anhydride are mixed in a molar ratio of 1:(1.8-2.2), and a catalyst for the synthesis of linalool acetate is added. The mixture is reacted at 70-90°C for 4-8 hours to obtain linalool acetate. The amount of catalyst added for the synthesis of linalool acetate is 3wt.%-8wt.% of the amount of linalool.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a catalyst for the synthesis of linaloacetate. This catalyst utilizes the synergistic effect of a Ti-doped mesoporous molecular sieve SBA-15 framework and its supported heteropolyacids. First, the Ti-doped SBA-15 framework introduces Ti into the SBA-15 molecular sieve to form a Ti-O-Si structure, generating medium-to-strong Lewis acid sites within the framework. Second, the large specific surface area and uniform pore structure of the SBA-15 mesoporous molecular sieve provide ample and suitable dispersion space for the heteropolyacids, achieving not only high loading of the heteropolyacids but also effectively preventing their aggregation and maintaining their properties. The presence of linalool and acetic anhydride hinders the stability and activity of the catalyst. Simultaneously, due to the small molecular size of linalool and acetic anhydride, the mesoporous channels of the Ti-doped mesoporous molecular sieve SBA-15 provide smooth diffusion pathways for these molecules, allowing reactants and products to rapidly enter and exit active sites. This effectively reduces internal diffusion limitations, further improving reaction efficiency and reducing side reactions. Furthermore, the supported heteropolyacid possesses extremely strong Brønsted acidity, which synergizes with the Lewis acid sites of the mesoporous molecular sieve, significantly enhancing the efficiency of catalytic esterification reactions, giving the catalyst excellent overall catalytic performance. Compared to existing phosphoric acid catalysts, this catalyst features high activity, recyclability, environmental friendliness, non-corrosiveness to equipment, low cost, and mild reaction conditions, effectively promoting the development of linalyl acetate production and meeting market demand.

[0017] This invention also provides a method for preparing the catalyst for the synthesis of linalyl acetate as described above. This method uses triblock copolymer P123 as a template agent dissolved in a first hydrochloric acid solution, providing a favorable template environment for the subsequent construction of an ordered mesoporous structure. The unique molecular structure of triblock copolymer P123 guides the ordered assembly of tetraethyl orthosilicate and tetrabutyl titanate under specific conditions, forming a Ti-doped mesoporous molecular sieve with a uniform pore structure. This molecular sieve possesses a Ti-O-Si structure and a large specific surface area, enabling the generation of medium-to-strong Lewis acid sites within the framework. Finally, the supported heteropolyacid with extremely strong Brønsted acidity synergistically enhances the efficiency of the esterification reaction. The stable structure allows the catalyst to maintain good catalytic performance even after multiple uses, improving catalyst reusability and reducing production costs. This method is simple, easy to operate, has mild reaction conditions, and is low-cost, providing a highly feasible industrial production route for the synthesis of linalyl acetate.

[0018] The above-mentioned catalyst for the synthesis of linalyl acetate is used in the preparation of linalyl acetate. This catalyst has the characteristics of high activity, recyclability, environmental protection and pollution-free, non-corrosive to equipment, low cost, and mild reaction conditions. It has been verified that under the optimal synthesis conditions, the conversion rate of linalool is not less than 95%, and the yield of linalyl acetate is not less than 88%, which can better meet the market demand for linalyl acetate and promote the development of related downstream industries. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a method for preparing a catalyst for the synthesis of linalyl acetate according to the present invention. Detailed Implementation

[0020] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0021] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0022] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0023] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0024] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0025] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0026] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0027] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0028] This invention discloses a catalyst for the synthesis of linalyl acetate, comprising a Ti-doped mesoporous molecular sieve SBA-15 framework, wherein the Ti-doped mesoporous molecular sieve SBA-15 framework is loaded with heteropoly acids; preferably, the heteropoly acids are one or more of phosphotungstic acid, phosphomolybdic acid and silicotungstic acid; in the Ti-doped mesoporous molecular sieve SBA-15 framework, the molar ratio of silicon atoms to titanium atoms is (10-30):1.

[0029] This catalyst utilizes the synergistic effect of a Ti-doped mesoporous molecular sieve SBA-15 framework and its supported heteropolyacids. Specifically, the Ti-doped SBA-15 framework introduces Ti into the SBA-15 molecular sieve to form a Ti-O-Si structure, generating medium-to-strong Lewis acid sites within the framework. Secondly, the large specific surface area and uniform pore structure of the SBA-15 mesoporous molecular sieve provide ample and suitable dispersion space for the heteropolyacids, enabling not only high loading of heteropolyacids but also effectively preventing their aggregation, thus ensuring the catalyst's stability and... Furthermore, due to the small molecular size of linalool and acetic anhydride, the mesoporous channels of the Ti-doped mesoporous molecular sieve SBA-15 provide smooth diffusion pathways for linalool and acetic anhydride molecules, allowing reactants and products to rapidly enter and exit active sites, effectively reducing internal diffusion limitations, further improving reaction efficiency, and reducing the occurrence of side reactions. Secondly, the supported heteropolyacid possesses extremely strong Brønsted acidity, which synergistically enhances the efficiency of catalytic esterification reactions with the Lewis acid sites of the mesoporous molecular sieve, giving the catalyst excellent overall catalytic performance. Compared with existing phosphoric acid catalysts, this catalyst features high catalyst activity, recyclability, environmental friendliness, non-corrosiveness to equipment, low cost, and mild reaction conditions, effectively promoting the development of linalyl acetate production and meeting market demand for linalyl acetate.

[0030] See Figure 1 The present invention also provides a method for preparing a catalyst for the synthesis of linalyl acetate as described above, comprising: S1: Dissolve the triblock copolymer P123 in a first hydrochloric acid solution to obtain a first mixture, specifically: triblock copolymer P123 (EO) 20 PO 70 EO 20 Add a hydrochloric acid solution with a concentration of 1.75-1.8 mol / L to the reaction flask, and stir in a water bath at 30-40℃ for 4-5 hours to completely dissolve the triblock copolymer P123 and obtain the first mixture.

[0031] S2: Tetrabutyl orthosilicate and tetrabutyl titanate are dissolved in a second hydrochloric acid solution to obtain a second mixture. Specifically, tetrabutyl orthosilicate and tetrabutyl titanate are placed in a reaction flask, and a hydrochloric acid solution with a concentration of 1.8-2.3 mol / L is added. The mixture is stirred in a water bath at 30-40℃ for 2-3 hours to obtain the second mixture. The molar ratio of tetrabutyl orthosilicate to tetrabutyl titanate is n, where n ranges from 10 to 30, representing the molar ratio of silicon to titanium atoms in the SBA-15 framework of the Ti-doped mesoporous molecular sieve.

[0032] S3: Add the second mixture to the first mixture to obtain a mixed reaction solution, specifically: The second mixture is added dropwise to the first mixture, and the mixture is stirred at 30-40℃ for 6-8 hours to obtain a mixed reaction solution. The molar ratio of the total molar amount of tetrabutyl orthosilicate and tetrabutyl titanate to the molar amount of triblock copolymer P123, hydrochloric acid, and water in the mixed reaction solution is (0.95-1):(0.016-0.017):(5.74-5.89):(175.4-175.7).

[0033] S4: The mixed reaction solution was sequentially subjected to crystallization, cooling, filtration, washing, drying, and a single calcination to obtain the Ti-doped mesoporous molecular sieve SBA-15 framework, specifically as follows: The mixture was placed in a high-pressure autoclave lined with polytetrafluoroethylene and crystallized in an oven at 100-120℃ for 24-36 hours. After crystallization, it was removed, cooled, filtered, washed until neutral, dried at room temperature, and then placed in a muffle furnace for calcination at 500-600℃ for 5-6 hours to remove the template agent, thus obtaining the Ti-doped mesoporous molecular sieve SBA-15 framework.

[0034] S5: The Ti-doped mesoporous molecular sieve SBA-15 framework was impregnated in a heteropoly acid solution, filtered, dried, and calcined a second time to obtain a catalyst for the synthesis of linalyl acetate, specifically: Prepare a heteropolyacid solution by deionizing water; Ti-doped mesoporous molecular sieve SBA-15 framework was added to a heteropoly acid solution, stirred at room temperature for 3-4 hours, filtered, dried at 80-100℃ for 2-4 hours, and then calcined in a muffle furnace at 150-200℃ for 2-4 hours to obtain a catalyst for the synthesis of linalyl acetate. The mass ratio of Ti-doped SBA-15 framework to water was 1:(15-20), and the mass percentage of heteropoly acid to Ti-doped SBA-15 framework was 10%-25%.

[0035] The applications of the above-mentioned catalysts used in the synthesis of linalyl acetate in the preparation of linalyl acetate include: Linalool and acetic anhydride are mixed at a molar ratio of 1:(1.8-2.2), and a catalyst for the synthesis of linaloacetate is added. The reaction is carried out at 70-90℃ for 4-8 hours to obtain linaloacetate. The amount of catalyst added is 3wt.%-8wt.% of the amount of linalool. After the reaction is completed, the catalyst is filtered out and can be recycled.

[0036] Example 1 Weigh 5g of triblock copolymer P123 (EO) 20 PO 70 EO 20 Add 150 mL of 1.8 mol / L hydrochloric acid to reaction flask A, and stir in a 40°C water bath for 5 h to completely dissolve the triblock copolymer P123, thus obtaining the first mixture.

[0037] Weigh 10.16 g of tetraethyl orthosilicate and 0.55 g of tetrabutyl titanate into reaction flask B, add 15 mL of 1.8 mol / L hydrochloric acid, and stir in a water bath at 40 °C for 2 h to obtain the second mixture.

[0038] The second mixture in reaction flask B was added dropwise to the first mixture in reaction flask A. After stirring at 40°C for 6 hours, a mixed reaction solution was obtained. The mixed reaction solution was placed in a high-pressure reactor lined with polytetrafluoroethylene and crystallized in an oven at 100°C for 36 hours. After cooling, filtration, washing until neutral, and drying at room temperature, it was placed in a muffle furnace and calcined at 550°C for 5 hours to remove the template agent, thus obtaining the Ti-doped mesoporous molecular sieve SBA-15 framework, denoted as Ti-SBA-15(30).

[0039] 1g of phosphotungstic acid (HPW) was weighed and added to 75g of deionized water to prepare a solution. Then, more than 5g of the prepared Ti-doped mesoporous molecular sieve SBA-15 framework Ti-SBA-15(30) was added. The mixture was stirred at room temperature for 3 h, filtered, dried at 100℃ for 2 h, and then calcined in a muffle furnace at 200℃ for 4 h to obtain a catalyst for the synthesis of linalyl acetate, denoted as 20% HPW / Ti-SBA-15(30).

[0040] The reaction was carried out in a three-necked flask. Linalool and acetic anhydride were mixed in a molar ratio of 1:1.8, and a catalyst for the synthesis of linal acetate was added. The reaction was carried out at 70°C and atmospheric pressure for 6 hours to obtain linal acetate. The mass percentage of the catalyst added for the synthesis of linal acetate was 5 wt.% of the linalool. The conversion rate of linalool was 92%, and the yield of linal acetate was 83%. After the reaction was completed, the catalyst was filtered out and could be recycled more than 5 times.

[0041] Example 2 Weigh 5g of triblock copolymer P123 (EO) 20 PO 70 EO 20 Add 150 mL of 1.75 mol / L hydrochloric acid to reaction flask A, and stir in a 30°C water bath for 5 h to completely dissolve the triblock copolymer P123, thus obtaining the first mixture.

[0042] Weigh 10.16 g of tetraethyl orthosilicate and 0.55 g of tetrabutyl titanate into reaction flask B, add 15 mL of 2.3 mol / L hydrochloric acid, and stir in a 30 °C water bath for 3 h to obtain the second mixture.

[0043] The second mixture in reaction flask B was added dropwise to the first mixture in reaction flask A, and the mixture was stirred at 30°C for 8 hours. The mixture was then placed in a high-pressure reactor lined with polytetrafluoroethylene and crystallized in an oven at 120°C for 24 hours. After crystallization, the mixture was removed, cooled, filtered, washed until neutral, and dried at room temperature. The mixture was then placed in a muffle furnace and calcined at 500°C for 6 hours to remove the template agent, resulting in a Ti-doped mesoporous molecular sieve SBA-15 framework, denoted as Ti-SBA-15 (30).

[0044] Weigh 0.5g of silicotungstic acid (HSiW) and add it to 100g of deionized water to prepare a solution. Then add more than 5g of the prepared Ti-doped mesoporous molecular sieve SBA-15 framework Ti-SBA-15(30), stir at room temperature for 4h, filter, dry at 80℃ for 4h, transfer to a muffle furnace and calcine at 150℃ for 4h. This catalyst is used to synthesize linalyl acetate and is denoted as 10% HSiW / Ti-SBA-15(30).

[0045] The reaction was carried out in a three-necked flask. Linalool and acetic anhydride were mixed in a molar ratio of 1:2, and a catalyst for the synthesis of linalyl acetate was added. The reaction was carried out at 80°C and atmospheric pressure for 4 hours to obtain linalyl acetate. The catalyst was added at a mass percentage of 8 wt.% of the linalool. The conversion rate of linalool was 90%, and the yield of linalyl acetate was 81%. After the reaction was completed, the catalyst was filtered out. The catalyst could be recycled more than 5 times.

[0046] Example 3 Weigh 5g of triblock copolymer P123 (EO) 20 PO 70 EO 20 Add 150 mL of 1.75 mol / L hydrochloric acid to reaction flask A, and stir in a 40°C water bath for 4 hours to completely dissolve the triblock copolymer P123, thus obtaining the first mixture.

[0047] Weigh 10.00g of tetraethyl orthosilicate and 0.82g of tetrabutyl titanate into reaction flask B, add 15mL of 2mol / L hydrochloric acid, and stir in a 40℃ water bath for 3h to obtain the second mixture.

[0048] The second mixture in reaction flask B was added dropwise to the first mixture in reaction flask A, and stirring was continued at 40°C for 6 hours. The mixed reaction solution was placed in a high-pressure reactor lined with polytetrafluoroethylene and crystallized in an oven at 100°C for 36 hours. After cooling, filtration, washing until neutral, and drying at room temperature, it was placed in a muffle furnace and calcined at 550°C for 5 hours to remove the template agent, thus obtaining the Ti-doped mesoporous molecular sieve SBA-15 framework, denoted as Ti-SBA-15 (20).

[0049] Weigh 0.75g of phosphotungstic acid (HPW) and add it to 100g of deionized water to prepare a solution. Then add more than 5g of the prepared Ti-doped mesoporous molecular sieve SBA-15 framework Ti-SBA-15(20), stir at room temperature for 3h, filter, dry at 100℃ for 3h, and calcine in a muffle furnace at 150℃ for 4h to obtain a catalyst for the synthesis of linalyl acetate, denoted as 15% HPW / Ti-SBA-15(20).

[0050] The reaction was carried out in a three-necked flask. Linalool and acetic anhydride were mixed in a molar ratio of 1:2, and a catalyst for the synthesis of linalyl acetate was added. The reaction was carried out at 90°C and atmospheric pressure for 6 hours to obtain linalyl acetate. The catalyst was added at a mass percentage of 6 wt.% of the linalool. The conversion rate of linalool was 95%, and the yield of linalyl acetate was 88%. After the reaction was completed, the catalyst was filtered out. The catalyst could be recycled more than 5 times.

[0051] Example 4 Weigh 5g of triblock copolymer P123 (EO) 20 PO 70 EO 20 Add 150 mL of 1.75 mol / L hydrochloric acid to reaction flask A, and stir in a 40°C water bath for 5 h to completely dissolve the triblock copolymer P123, thus obtaining the first mixture.

[0052] Weigh 10.00g of tetraethyl orthosilicate and 0.82g of tetrabutyl titanate into reaction flask B, add 15mL of 1.8mol / L hydrochloric acid, and stir in a 40℃ water bath for 2h to obtain the second mixture.

[0053] The second mixture in reaction flask B was added dropwise to the first mixture in reaction flask A, and stirring was continued at 40°C for 7 hours. The mixed reaction solution was then placed in a high-pressure reactor lined with polytetrafluoroethylene and crystallized in an oven at 120°C for 24 hours. After cooling, filtration, washing until neutral, and drying at room temperature, it was then placed in a muffle furnace and calcined at 600°C for 5 hours to remove the template agent, yielding the Ti-doped mesoporous molecular sieve SBA-15 framework, denoted as Ti-SBA-15 (20).

[0054] 1g of phosphomolybdic acid (HPMo) was weighed and added to 75g of deionized water to prepare a solution. Then, more than 5g of the prepared Ti-doped mesoporous molecular sieve SBA-15 framework Ti-SBA-15(20) was added. The mixture was stirred at room temperature for 4h, filtered, dried at 100℃ for 4h, and then calcined in a muffle furnace at 200℃ for 2h to obtain a catalyst for the synthesis of linalyl acetate, denoted as 20% HPMo / Ti-SBA-15(20).

[0055] The reaction was carried out in a three-necked flask. Linalool and acetic anhydride were mixed in a molar ratio of 1:2.2, and a catalyst for the synthesis of linalyl acetate was added. The reaction was carried out at 90°C and atmospheric pressure for 8 hours to obtain linalyl acetate. The catalyst was added at a mass percentage of 3 wt.% of linalool. The conversion rate of linalool was 94%, and the yield of linalyl acetate was 85%. After the reaction was completed, the catalyst was filtered out. The catalyst could be recycled more than 5 times.

[0056] Example 5 Weigh 4.7g of triblock copolymer P123 (EO) 20 PO 70 EO 20 Add 150 mL of 1.76 mol / L hydrochloric acid to reaction flask A, and stir in a 30°C water bath for 5 h to completely dissolve the triblock copolymer P123, thus obtaining the first mixture.

[0057] Weigh 9.55g of tetraethyl orthosilicate and 1.56g of tetrabutyl titanate into reaction flask B, add 15mL of 2.2mol / L hydrochloric acid, and stir in a 30℃ water bath for 3h to obtain the second mixture.

[0058] The second mixture in reaction flask B was added dropwise to the first mixture in reaction flask A, and the mixture was stirred at 30°C for 8 hours. The mixture was then placed in a high-pressure reactor lined with polytetrafluoroethylene and crystallized in an oven at 110°C for 36 hours. After crystallization, the mixture was removed, cooled, filtered, washed until neutral, and dried at room temperature. The mixture was then placed in a muffle furnace and calcined at 600°C for 6 hours to remove the template agent, resulting in the Ti-doped mesoporous molecular sieve SBA-15 framework, denoted as Ti-SBA-15 (10).

[0059] Weigh 0.75g of phosphomolybdic acid (HPMo) and add it to 80g of deionized water to prepare a solution. Then add more than 5g of the prepared Ti-doped mesoporous molecular sieve SBA-15 framework Ti-SBA-15(10), stir at room temperature for 3h, filter, dry at 100℃ for 4h, and calcine in a muffle furnace at 200℃ for 3h to obtain a catalyst for the synthesis of linalyl acetate, denoted as 15% HPMo / Ti-SBA-15(10).

[0060] The reaction was carried out in a three-necked flask. Linalool and acetic anhydride were mixed in a molar ratio of 1:2, and a catalyst for the synthesis of linalyl acetate was added. The reaction was carried out at 90°C and atmospheric pressure for 6 hours to obtain linalyl acetate. The catalyst was added at a mass percentage of 5 wt.% of the linalool. The conversion rate of linalool was 94%, and the yield of linalyl acetate was 86%. After the reaction was completed, the catalyst was filtered out. The catalyst could be recycled more than 5 times.

[0061] Example 6 Weigh 5g of triblock copolymer P123 (EO) 20 PO 70 EO 20 Add 150 mL of 1.75 mol / L hydrochloric acid to reaction flask A, and stir in a 40°C water bath for 4 hours to completely dissolve the triblock copolymer P123, thus obtaining the first mixture.

[0062] Weigh 9.07 g of tetraethyl orthosilicate and 1.48 g of tetrabutyl titanate into reaction flask B, add 15 mL of 2.3 mol / L hydrochloric acid, and stir in a 40 °C water bath for 2 h to obtain the second mixture.

[0063] The second mixture in reaction flask B was added dropwise to the first mixture in reaction flask A, and the mixture was stirred at 40°C for 6 hours. The mixture was then placed in a high-pressure reactor lined with polytetrafluoroethylene and crystallized in an oven at 100°C for 36 hours. After crystallization, the mixture was removed, cooled, filtered, washed until neutral, and dried at room temperature. The mixture was then placed in a muffle furnace and baked at 550°C for 5 hours to remove the template agent, resulting in the Ti-doped mesoporous molecular sieve SBA-15 framework, denoted as Ti-SBA-15 (10).

[0064] Weigh 1.25g of silicotungstic acid (HSiW) and add it to 95g of deionized water to prepare a solution. Then add more than 5g of the prepared Ti-doped mesoporous molecular sieve SBA-15 framework Ti-SBA-15(10), stir at room temperature for 3h, filter, dry at 90℃ for 3h, transfer to a muffle furnace and calcine at 150℃ for 4h to obtain a catalyst for the synthesis of linalyl acetate, denoted as 25% HSiW / Ti-SBA-15(10).

[0065] The reaction was carried out in a three-necked flask. Linalool and acetic anhydride were mixed in a molar ratio of 1:2.1, and a catalyst for the synthesis of linalyl acetate was added. The reaction was carried out at 90°C and atmospheric pressure for 6 hours to obtain linalyl acetate. The catalyst was added at a mass percentage of 6 wt.% of the linalool. The conversion rate of linalool was 93%, and the yield of linalyl acetate was 83%. After the reaction was completed, the catalyst was filtered out. The catalyst could be recycled more than 5 times.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.

Claims

1. A catalyst for the synthesis of linalyl acetate, characterized in that, The invention includes a Ti-doped mesoporous molecular sieve SBA-15 framework, wherein the Ti-doped mesoporous molecular sieve SBA-15 framework is loaded with heteropoly acids.

2. The catalyst for synthesizing linalyl acetate according to claim 1, characterized in that, The heteropolyacid is one or more of phosphotungstic acid, phosphomolybdic acid, and silicotungstic acid.

3. The catalyst for synthesizing linalyl acetate according to claim 1, characterized in that, In the Ti-doped mesoporous molecular sieve SBA-15 framework, the molar ratio of silicon atoms to titanium atoms is (10-30):

1.

4. A method for preparing a catalyst for the synthesis of linalyl acetate as described in any one of claims 1-3, characterized in that, include: The triblock copolymer P123 was dissolved in a first hydrochloric acid solution to obtain a first mixture; Tetrabutyl orthosilicate and tetrabutyl titanate are dissolved in a second hydrochloric acid solution to obtain a second mixture; The second mixture is added to the first mixture to obtain a mixed reaction solution; The mixed reaction solution was subjected to crystallization, cooling, filtration, washing, drying and calcination in sequence to obtain the Ti-doped mesoporous molecular sieve SBA-15 framework. Ti-doped mesoporous molecular sieve SBA-15 framework was impregnated in a heteropoly acid solution, filtered, dried, and calcined a second time to obtain a catalyst for the synthesis of linalyl acetate.

5. The method for preparing the catalyst for synthesizing linalyl acetate according to claim 4, characterized in that, The first hydrochloric acid solution has a concentration of 1.75-1.8 mol / L.

6. The method for preparing the catalyst for synthesizing linalyl acetate according to claim 5, characterized in that, The molar ratio of tetraethyl orthosilicate to tetrabutyl titanate is (10-30):1; the second hydrochloric acid solution has a concentration of 1.8-2.3 mol / L.

7. The method for preparing the catalyst for synthesizing linalyl acetate according to claim 6, characterized in that, In the mixed reaction solution, the total molar amount of tetrabutyl orthosilicate and tetrabutyl titanate to the molar ratio of triblock copolymer P123, hydrochloric acid and water is (0.95-1):(0.016-0.017):(5.74-5.89):(175.4-175.7).

8. The method for preparing the catalyst for synthesizing linalyl acetate according to claim 4, characterized in that, The crystallization treatment temperature is 100-120℃, and the crystallization time is 24-36h; the first calcination temperature is 500-600℃, and the first calcination time is 5-6h.

9. The method for preparing the catalyst for synthesizing linalyl acetate according to claim 4, characterized in that, In the heteropoly acid solution, the mass ratio of heteropoly acid to Ti-doped mesoporous molecular sieve SBA-15 framework is 10%-25%, and the mass ratio of Ti-doped mesoporous molecular sieve SBA-15 framework to water is 1:(15-20); the secondary calcination temperature is 150-200℃, and the secondary calcination time is 2-4h.

10. The use of the catalyst for the synthesis of linalyl acetate according to any one of claims 1-3 in the preparation of linalyl acetate, characterized in that, include: Linalool and acetic anhydride are mixed in a molar ratio of 1:(1.8-2.2), and a catalyst for the synthesis of linalool acetate is added. The mixture is reacted at 70-90°C for 4-8 hours to obtain linalool acetate. The amount of catalyst added for the synthesis of linalool acetate is 3wt.%-8wt.% of the amount of linalool.

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