A kind of synthetic method of cyclohexyloxyacetic acid ester

Abstract

The invention discloses a method for synthesizing cyclohexyl acetate. The method uses phenoxyacetic acid ester and hydrogen as raw materials, performs a hydrogenation reaction in the presence of a catalyst, and generates the cyclohexyl acetate. The catalyst is a supported catalyst and includes a carrier and a metal carbide, wherein the metal carbide contains at least two metal elements selected from In, Co, Ni and Zn. The method has a fast reaction rate and a short reaction time, and the catalyst used in the reaction can significantly inhibit the activation of the C-O bond of phenoxyacetic acid ester, reduce the occurrence of side reactions, and improve the reaction selectivity of the hydrogenation reaction and the yield of the target product cyclohexyl acetate.

Description

Technical Field

[0001] The invention relates to a method for synthesizing cyclohexyloxyacetic acid ester. Background Art

[0002] Cyclohexyl acetate compounds have important application value in industry. For example, allyl cyclohexyl acetate (CAS: 68901-15-5) is an important galbanum fragrance, which can emit a Persian base fragrance like green pineapple and green apple for a long time, and has good compound performance with other substances. It is widely used in daily chemicals, tobacco, food and other fields.

[0003] At present, the mainstream process for the production of allyl cyclohexyl acetate is the esterification and dehydration of cyclohexyl acetate and allyl alcohol. The reaction formula is as follows: However, due to the strong acidity of cyclohexyloxyacetic acid, it is easy to cause corrosion to equipment in actual production. In addition, when it undergoes esterification reaction with allyl alcohol, the acid in the reaction system will cause the allyl alcohol to undergo polymerization side reaction, resulting in a significant decrease in yield.

[0004] Chinese patent CN101798267A discloses a method for producing allyl cyclohexyl acetate, wherein ethyl cyclohexyl acetate is prepared by hydrogenation using ethyl phenoxyacetate as a raw material, and the hydrogenation catalyst is a carbon-supported noble metal catalyst (ruthenium, rhodium, palladium, platinum), and ethyl cyclohexyl acetate is then subjected to an ester exchange reaction with allyl alcohol under the action of a base to produce allyl cyclohexyl acetate. The synthetic route of the patent is as follows:

[0005] This method can effectively solve the problems of cyclohexyloxyacetic acid as raw material, easy corrosion of equipment and easy polymerization of allyl alcohol. However, the hydrogenation catalyst used in this method has low activity, resulting in too long time required for the first step of hydrogenation reaction; and due to the weak interaction between the carbon carrier and the metal, the service life of the hydrogenation catalyst is poor and the actual number of applications is small; at the same time, the catalyst is expensive and is subject to certain restrictions in industrial application.

[0006] Cheaper non-precious metal catalysts such as supported Ni-based and Co-based catalysts have the advantages of excellent benzene ring hydrogenation activity, stability and easy recovery, and are widely used in the field of fine chemicals. However, in addition to hydrogenating the benzene ring under high temperature and high pressure, this type of catalyst will also activate the CO bond on phenoxyacetate, causing the benzene ring on phenoxyacetate to fall off, reducing the selectivity of the hydrogenation reaction and the yield of the target product cyclohexyl acetate. Summary of the invention

[0007] In view of the shortcomings and deficiencies of the prior art, the present invention provides a method for synthesizing cyclohexyl acetate, which has a fast reaction rate and a short reaction time, can improve the reaction selectivity and yield of cyclohexyl acetate, is relatively low in cost, and is not prone to corrosion of equipment.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A method for synthesizing cyclohexyl acetate comprises taking phenoxyacetate and hydrogen as raw materials, carrying out a hydrogenation reaction in the presence of a catalyst to generate the cyclohexyl acetate, wherein the catalyst is a supported catalyst and comprises a carrier and a metal carbide, wherein the metal carbide contains at least two metal elements selected from In, Co, Ni and Zn.

[0010] In some embodiments, the metal carbide contains two metal elements, In and Ni, and the molar ratio of the In element to the Ni element is 1:1-3.

[0011] In some embodiments, the metal carbide contains two metal elements, In and Co, and the molar ratio of the In element to the Co element is 1:1-3.

[0012] In some embodiments, the metal carbide contains two metal elements, Zn and Ni, and the molar ratio of the Zn element to the Ni element is 1:1-3.

[0013] In some embodiments, the metal carbide is selected from InNi3C 0.5 、Co3InC 0.75 and ZnNi3C 0.7 A combination of one or more of .

[0014] In some embodiments, the support is selected from a combination of one or more of silica, alumina, titania, zirconia, cerium oxide, activated carbon and molecular sieves.

[0015] Preferably, the carrier is selected from silicon dioxide or titanium dioxide.

[0016] In some embodiments, the specific surface area of ​​the carrier is 50 to 500 m 2 / g.

[0017] In some embodiments, the mass percentage of the metal carbide in the catalyst is 1-50%.

[0018] The inventors have found through research that the use of a supported catalyst containing a metal carbide of at least two metal elements selected from In, Co, Ni and Zn can better inhibit the breaking of the CO bond in phenoxyacetate, thereby improving the selectivity of the hydrogenation reaction of phenoxyacetate and further increasing the yield of the target product cyclohexyloxyacetate, compared with the use of supported catalysts such as ordinary Ni nanoparticles or Co nanoparticles, or supported catalysts such as ordinary InNi alloys.

[0019] In some embodiments, the catalyst is prepared by a preparation method comprising the following steps: 1) adding a precipitant to a mixture of water, a carrier and at least two active metal salts for precipitation, and obtaining a supported metal oxide precursor after aging, filtering, drying and calcining; 2) subjecting the supported metal oxide precursor to a reduction carbonization treatment in an atmosphere of synthesis gas to obtain the supported catalyst; the active metal salt is selected from salts of In, Co, Ni or Zn.

[0020] In some embodiments, the active metal salt is selected from nitrates, sulfates, acetylacetonates or acetates of In, Co, Ni or Zn.

[0021] In some embodiments, in step 1), the precipitant is selected from a combination of at least one or more of sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonium bicarbonate, aqueous ammonia and urea.

[0022] Preferably, the precipitant is added in the form of an aqueous solution, and the molar concentration of the precipitant in the aqueous solution is 0.02 to 5 mol / L.

[0023] In some embodiments, in step 1), the precipitation temperature is 20-90°C.

[0024] In some embodiments, in step 1), the aging temperature is 20-90°C.

[0025] In some embodiments, in step 1), the precipitation time is 0.5 to 5 hours.

[0026] In some embodiments, in step 1), the aging time is 0.5 to 24 hours.

[0027] In some embodiments, the molar concentration of the active metal salt in the mixture is 0.05 to 10 mol / L.

[0028] In some embodiments, washing is performed before drying in step 1), and the washing is performed until the filtrate is neutral.

[0029] In some embodiments, in step 1), the calcination temperature is 300-600°C.

[0030] In some embodiments, in step 2), the molar ratio of carbon monoxide to hydrogen in the synthesis gas is 1:0.1-50.

[0031] In some embodiments, in step 2), the reduction carbonization temperature is 350-800°C.

[0032] In some embodiments, in step 2), the reduction carbonization time is 0.5 to 24 hours.

[0033] In some embodiments, the cyclohexyloxyacetic acid ester is selected from a combination of one or more of cyclohexyloxyacetic acid methyl ester, cyclohexyloxyacetic acid ethyl ester, cyclohexyloxyacetic acid allyl ester and cyclohexyloxyacetic acid hexyl ester.

[0034] In some embodiments, the synthesis method comprises the following steps: 1) adding the phenoxyacetic acid ester and the catalyst into a reactor, introducing nitrogen into the reactor to replace the air therein; 2) heating the reactor to a reaction temperature, introducing hydrogen into the reactor for reaction, and introducing hydrogen into the reactor continuously or intermittently during the reaction process to maintain a stable pressure in the reactor. This synthesis method is an intermittent method.

[0035] In some embodiments, in step 1), the mass ratio of the catalyst to phenoxyacetic acid ester is 1:5-1000.

[0036] In some embodiments, in step 2), the reaction temperature is 100-200°C.

[0037] In some embodiments, in step 2), the pressure is 0.5-6 MPa.

[0038] In some embodiments, in step 2), the reaction time is 1 to 36 hours.

[0039] In some embodiments, the synthesis method comprises the following steps: 1) loading the catalyst in a fixed bed reactor, introducing nitrogen into the fixed bed reactor to replace the air therein; 2) heating the fixed bed reactor to a reaction temperature, and then introducing hydrogen into the fixed bed reactor so that the pressure in the fixed bed reactor rises to the reaction pressure; 3) continuously introducing hydrogen and phenoxyacetic acid ester into the fixed bed reactor for reaction. This synthesis method is a continuous method.

[0040] In some embodiments, in step 2), the reaction temperature is 100-200°C.

[0041] In some embodiments, in step 2), the reaction pressure is 0.5-6 MPa.

[0042] In some embodiments, in step 3), the mass space velocity of the phenoxyacetic acid ester is 0.5 to 5 h -1 .

[0043] In some embodiments, in step 3), the molar ratio of hydrogen to phenoxyacetic acid ester is 3 to 40:1.

[0044] The present invention also provides the above-mentioned catalyst. The catalyst has high reaction activity and reaction selectivity, and when used for hydrogenation synthesis of cyclohexyloxyacetic acid ester, the reaction rate and reaction yield can be significantly improved, and the catalyst has good stability, and the catalyst activity will not be significantly reduced after being used 10 times in an intermittent reaction and after reacting for 500 hours in a continuous reaction.

[0045] Compared with the prior art, the present invention has the following advantages:

[0046] The invention adopts a supported catalyst including a carrier and a metal carbide, wherein the metal carbide contains at least two metal elements selected from In, Co, Ni and Zn, so that the reaction activity of the hydrogenation reaction of phenoxyacetic acid ester can be improved, the reaction rate can be accelerated, and the time of the hydrogenation reaction can be shortened. At the same time, the catalyst can significantly inhibit the activation of the CO bond of phenoxyacetic acid ester, reduce the occurrence of side reactions, and improve the reaction selectivity of the hydrogenation reaction and the yield of the target product cyclohexyloxyacetic acid ester. The synthesis method of the invention has a relatively low cost, and the reaction conditions are not easy to corrode the reaction equipment.

[0047] Compared with the noble metal catalysts of the conventional hydrogenation reaction, the catalyst of the present invention has lower cost and better catalytic activity, and can better inhibit the occurrence of the CO bond breaking side reaction of the reaction raw material cyclohexyloxyacetic acid ester, and the catalyst has better stability. After being used 10 times in the intermittent reaction and after reacting for 500 hours in the continuous reaction, the catalyst activity will not be significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 The supported metal carbide catalyst InNi3C in Preparation Example 1 0.5 / SiO2、Co3InC 0.75 / SiO2, ZnNi3C 0.7 / X-ray diffraction spectrum of SiO2;

[0049] Figure 2 The supported metal carbide catalyst InNi3C in Preparation Example 1 0.5 / SEM image of SiO2;

[0050] Figure 3 The supported metal carbide catalyst InNi3C in Preparation Example 1 0.5 / SiO2 500h stability test results. DETAILED DESCRIPTION

[0051] The present invention is further described below in conjunction with the examples. However, the present invention is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to the different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0052] Preparation Example 1

[0053] This preparation example provides a supported catalyst, and its preparation method is as follows:

[0054] 1) Weigh 0.99 kg of nickel nitrate hexahydrate, 0.443 kg of indium nitrate pentahydrate, and 10 kg of deionized water into a 50 L reactor, stir and dissolve at room temperature, then add 2.5 kg of silica sol with a mass concentration of 40 wt%, and continue stirring for 30 min; heat the reactor to 50 ° C and keep the temperature in the reactor unchanged; add 20 kg of sodium carbonate aqueous solution (molar concentration of 0.5 mol / L) into the reactor through a peristaltic pump for precipitation reaction, and the feeding time is 1 h; after the precipitation is completed, maintain the reactor at 50 ° C for aging treatment for 6 h; filter and wash the materials in the reactor until the filtrate shows neutrality; place the filter cake in a 100 ° C oven to dry, and then roast it in an air atmosphere at 400 ° C for 2 h to obtain In2O3-NiO / SiO2 precursor.

[0055] 2) 1 kg of the In2O3-NiO / SiO2 precursor prepared in step 1) was placed in a rotary furnace, and then a synthesis gas with a molar ratio of H2 to CO of 2 was introduced (the flow rate was 100 mL / min), and the temperature was raised to 450°C for reduction carbonization. After reacting for 4 h, the supported InNi3C was obtained. 0.5 / SiO2 catalyst.

[0056] The prepared supported InNi3C 0.5 The mass percentage of Ni in the / SiO2 catalyst is 16.2%, and the mass percentage of In is 10.1%. 0.5 The X-ray diffraction spectrum of / SiO2 catalyst is as follows Figure 1 As shown, it can be confirmed that the carrier SiO2 is loaded with InNi3C 0.5 . Loaded InNi3C 0.5 SEM images of the / SiO2 catalyst are shown in Figure 2 As shown, it can be seen that the morphology of the catalyst is a flake stacking structure.

[0057] In this preparation example, the nickel nitrate hexahydrate and indium nitrate pentahydrate in step 1) can be replaced by cobalt nitrate hexahydrate and indium nitrate pentahydrate or nickel nitrate hexahydrate and zinc nitrate hexahydrate, and the other conditions remain unchanged, and supported metal carbide catalysts of different compositions can be prepared, respectively, and are recorded as Co3InC 0.75 / SiO2, ZnNi3C 0.7 / SiO2.

[0058] In this preparation example, the silicon dioxide in step 1) can be replaced by aluminum oxide, titanium dioxide, zirconium dioxide, cerium oxide, activated carbon and ZSM-5 molecular sieve respectively, and the other conditions remain unchanged to obtain InNi3C with different carrier loads. 0.5 Catalysts, respectively InNi3C 0.5 / Al2O3, InNi3C 0.5 / TiO2, InNi3C 0.5 / ZrO2,InNi3C 0.5 / CeO2, InNi3C 0.5 / C, InNi3C 0.5 / ZSM-5.

[0059] Comparative Preparation Example 1

[0060] This comparative preparation example provides an alloy type supported catalyst, and its preparation method is as follows:

[0061] 1) Weigh 0.99 kg of nickel nitrate hexahydrate, 0.443 kg of indium nitrate pentahydrate, and 10 kg of deionized water into a 50 L reactor, stir and dissolve at room temperature, then add 2.5 kg of silica sol with a mass concentration of 40 wt%, and continue stirring for 30 min; heat the reactor to 50 ° C and keep the temperature in the reactor unchanged; add 20 kg of sodium carbonate aqueous solution (molar concentration of 0.5 mol / L) into the reactor through a peristaltic pump for precipitation reaction, and the feeding time is 1 h; after the precipitation is completed, maintain the reactor at 50 ° C for aging treatment for 6 h; filter and wash the materials in the reactor until the filtrate shows neutrality; place the filter cake in a 100 ° C oven to dry, and then roast it in an air atmosphere at 400 ° C for 2 h to obtain In2O3-NiO / SiO2 precursor.

[0062] 2) Place 1 kg of In2O3-NiO / SiO2 obtained in step 1) into a rotary furnace, introduce H2 (at a flow rate of 100 mL / min), raise the temperature to 450°C for reduction, and take it out after 4 hours to obtain a supported InNi3 / SiO2 catalyst.

[0063] According to plasma inductively coupled atomic absorption spectrometry analysis, the mass percentage of Ni in the prepared supported InNi3 / SiO2 catalyst is 16.9%, and the mass percentage of In is 10.8%.

[0064] In this comparative preparation example, the nickel nitrate hexahydrate and indium nitrate pentahydrate in step 1) can be replaced by cobalt nitrate hexahydrate and indium nitrate pentahydrate or nickel nitrate hexahydrate and zinc nitrate hexahydrate, and the other conditions remain unchanged. Supported metal catalysts of different compositions can be prepared, which are respectively recorded as Co3In / SiO2 and ZnNi3 / SiO2.

[0065] Comparative Preparation Example 2

[0066] This comparative preparation example provides a supported single metal carbide catalyst, and its preparation method is as follows:

[0067] 1) Weigh 0.433 kg of indium nitrate pentahydrate and 10 kg of deionized water into a 50 L reactor, stir and dissolve at room temperature, then add 2.5 kg of silica sol with a mass concentration of 40 wt%, and continue stirring for 30 min; heat the reactor to 50 ° C and keep the temperature in the reactor unchanged; add 5 kg of sodium carbonate aqueous solution (molar concentration of 0.5 mol / L) into the reactor through a peristaltic pump for precipitation reaction, and the feeding time is 1 h; after the precipitation is completed, maintain the reactor at 50 ° C for aging treatment for 6 h; filter and wash the materials in the reactor until the filtrate is neutral; dry the filter cake in a 100 ° C oven, and then calcine it in an air atmosphere at 400 ° C for 2 h to obtain an In2O3 / SiO2 precursor.

[0068] 2) Place 1 kg of the In2O3 / SiO2 precursor obtained in step 1) into a rotary furnace, then introduce a synthesis gas with a molar ratio of H2 to CO of 2 (at a flow rate of 100 mL / min), heat to 450°C for reduction and carbonization, and take out after reacting for 4 hours to obtain a supported InC / SiO2 catalyst.

[0069] Comparative Preparation Example 3

[0070] This comparative preparation example provides a supported single metal carbide catalyst, and its preparation method is as follows:

[0071] 1) Weigh 0.99 kg of nickel nitrate hexahydrate and 10 kg of deionized water into a 50 L reactor, stir and dissolve at room temperature, then add 2.5 kg of silica sol with a mass concentration of 40 wt%, and continue stirring for 30 min; heat the reactor to 50 ° C and keep the temperature in the reactor unchanged; add 15 kg of sodium carbonate aqueous solution (molar concentration of 0.5 mol / L) into the reactor through a peristaltic pump for precipitation reaction, and the feeding time is 1 h; after the precipitation is completed, maintain the reactor at 50 ° C for aging treatment for 6 h; filter and wash the materials in the reactor until the filtrate shows neutrality; dry the filter cake in a 100 ° C oven, and then roast it in an air atmosphere at 400 ° C for 2 h to obtain a NiO / SiO2 precursor.

[0072] 2) Place 1 kg of the NiO / SiO2 precursor obtained in step 1) into a rotary furnace, then introduce a synthesis gas with a molar ratio of H2 to CO of 2 (at a flow rate of 100 mL / min), heat to 450°C for reduction and carbonization, and take out after reacting for 4 hours to obtain a supported Ni3C / SiO2 catalyst.

[0073] Comparative Preparation Example 4

[0074] This comparative preparation example provides a supported molybdenum carbide catalyst, and its preparation method is as follows:

[0075] 1) Weigh 1.433 kg of ammonium molybdate, add 2.5 kg of silica sol with a mass concentration of 40 wt%, stir thoroughly, evaporate the water, and then calcine at 500 ° C in air atmosphere for 2 h to obtain MoO3 / SiO2 precursor.

[0076] 2) Place 1 kg of the NiO / SiO2 precursor obtained in step 1) into a rotary furnace, then introduce a synthesis gas with a molar ratio of H2 to CO of 2 (at a flow rate of 100 mL / min), heat to 650°C for reduction and carbonization, and take out after reacting for 4 hours to obtain a supported Mo2C / SiO2 catalyst.

[0077] Example 1

[0078] This embodiment provides a method for synthesizing methyl cyclohexylacetate, and the specific steps are as follows:

[0079] 0.3 kg of each catalyst in Table 1 (derived from Preparation Example 1, Comparative Preparation Examples 1-4) and 30 kg of methyl phenoxyacetate were put into a 50 L stainless steel reactor, replaced with nitrogen 5 times, and then the reactor was heated to 150 ° C. Hydrogen was introduced into the reactor, and the pressure of the reactor was controlled at 4 MPa. After 10 hours of reaction, heating was stopped. After cooling, the catalyst was separated from the reaction solution by filtration, and the quantitative analysis of the reaction solution was performed on an Agilent 7890 gas chromatograph, and the chromatographic column HP-INNOWax and FID detector were used for detection.

[0080] Table 1 shows the results of the reaction performance of each catalyst. As can be seen from Table 1, compared with the silica-supported alloy catalyst in Comparative Preparation Example 1, the supported single metal carbide catalyst in Comparative Preparation Examples 2-3, and the supported molybdenum carbide catalyst in Comparative Preparation Example 4, the catalyst of the present invention has significantly higher phenoxyacetic acid methyl ester conversion rate and cyclohexyloxyacetic acid methyl ester selectivity.

[0081] Table 1: Reaction performance results of the catalysts prepared in Preparation Example 1 and Comparative Preparation Examples 1-4

[0082] catalyst Methyl phenoxyacetate conversion rate (%) Cyclohexyloxyacetic acid methyl ester selectivity (%) <![CDATA[InNi3C 0.5 / SiO2]]> 99.9 93.3 <![CDATA[Co3InC 0.75 / SiO2]]> 99.9 90.7 <![CDATA[ZnNi3C 0.7 / SiO2]]> 99.8 91.6 <![CDATA[InNi3 / SiO2]]> 77.7 80.2 <![CDATA[Co3In / SiO2]]> 80.2 76.5 <![CDATA[ZnNi3 / SiO2]]> 75.6 81.4 <![CDATA[InC / SiO2]]> 0.1 21.2 <![CDATA[Ni3C / SiO2]]> 45.1 46.7 <![CDATA[Mo2C / SiO2]]> 21.4 16.5

[0083] Table 2 shows the reaction performance results of the catalysts prepared with different carriers in Preparation Example 1. 0.5 The catalysts all have good activity, among which silicon dioxide and titanium dioxide have the best performance.

[0084] Table 2: Reaction performance of different supported catalysts in Preparation Example 1

[0085] catalyst Methyl phenoxyacetate conversion rate (%) Cyclohexyloxyacetic acid methyl ester selectivity (%) <![CDATA[InNi3C 0.5 / SiO2]]> 99.9 93.3 <h2 style=";text-align:left;direction:ltr"><![CDATA[InNi3C <h2 style=";text-align:left;direction:ltr"> 0.5 <h2 style=";text-align:left;direction:ltr"> / Al2O3]]><h2 style=";text-align:left;direction:ltr"> 99.9 83.7 <![CDATA[InNi3C 0.5 / TiO2]]> 99.9 92.8 <![CDATA[InNi3C 0.5 / ZrO2]]> 97.6 89.2 <![CDATA[InNi3C 0.5 / CeO2]]> 93.5 88.4 <![CDATA[InNi3C 0.5 / C]]> 99.9 87.6 <![CDATA[InNi3C 0.5 / ZSM-5]]> 99.9 83.1

[0086] Example 2

[0087] Using the conditions of Example 1, the InNi3C 0.5 / SiO2 catalyst was used for the experiment. The results are shown in Table 3. It can be seen that after 10 times of catalyst application, InNi3C 0.5 / SiO2 catalyst showed no signs of deactivation, indicating that the catalyst has excellent stability.

[0088] Table 3: InNi3C 0.5 / SiO2 catalyst application performance

[0089]

[0090]

[0091] Example 3

[0092] Evaluation of InNi3C in a reactor 0.5 / SiO2 catalyst was used for the reaction performance of different phenoxyacetic acid esters. 0.5 / SiO2 catalyst and 30kg of phenoxyacetic acid ester in Table 4 were put into a 50L stainless steel reactor. After nitrogen replacement 5 times, the reactor was heated to 150°C, hydrogen was introduced, and the pressure of the reactor was controlled at 4MPa. After 10 hours of reaction, heating was stopped. After cooling, the catalyst was separated from the reaction liquid by filtration. The quantitative analysis of the reaction liquid was carried out on an Agilent 7890 gas chromatograph, and the chromatographic column HP-INNOWax and FID detector were used for detection.

[0093] The results are shown in Table 4. 0.5 / SiO2 catalyst has excellent activity for various phenoxyacetic acid esters.

[0094] Table 4: Effect of different substrates on reaction performance

[0095] Substrate Phenoxyacetic acid ester conversion rate (%) Cyclohexyl acetate selectivity (%) Methyl phenoxyacetate 99.9 93.3 Ethyl phenoxyacetate 99.9 93.8 Allyl phenoxyacetate 97.6 94.3 Hexyl phenoxyacetate 94.2 95.1

[0096] Example 4

[0097] The InNi3C prepared in Example 1 was investigated in a fixed bed reactor. 0.5 / SiO2 catalyst for the synthesis of methyl cyclohexyl acetate reaction performance. A stainless steel tube was used as the reactor, with an outer diameter of 45 mm, an inner diameter of 37 mm, and a length of 2200 mm. The catalyst loading was 1450 g (cylindrical: 3 mm in diameter, 5 mm in height; bulk density 0.8 g / mL). The reaction conditions were a reaction temperature of 150 ° C, a reaction pressure of 4 MPa, and a mass liquid hourly space velocity of methyl phenoxyacetate of 0.5 h -1 , hydrogen is the hydrogenating agent, and the molar ratio of hydrogen to methyl phenoxyacetate is 10. A 500-hour stability test was performed, and the results were as follows Figure 3 As shown in the figure, it can be seen that in the 500-hour stability test, methyl phenoxyacetate is basically completely converted, and the selectivity of methyl cyclohexylacetate is maintained at about 93%, indicating that the InNi3C prepared in Preparation Example 1 0.5 / SiO2 catalyst has excellent reaction activity and stability.

[0098] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

[0099] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

Claims

1. A method for synthesizing cyclohexyl acetate, which uses phenoxyacetic acid ester and hydrogen as raw materials, and performs a hydrogenation reaction in the presence of a catalyst to produce the cyclohexyl acetate, characterized in that: The catalyst is a supported catalyst and comprises a carrier and a metal carbide; the metal carbide contains two metal elements, In and Ni, and the molar ratio of the In element to the Ni element is 1:1-3, or the metal carbide contains two metal elements, In and Co, and the molar ratio of the In element to the Co element is 1:1-3, or the metal carbide contains two metal elements, Zn and Ni, and the molar ratio of the Zn element to the Ni element is 1:1-3; the carrier is selected from a combination of one or more of silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide, cerium oxide, activated carbon and molecular sieves; the mass percentage of the metal carbide in the catalyst is 1-50%.

2. The method for synthesizing cyclohexyloxyacetic acid ester according to claim 1, characterized in that: The metal carbide is selected from InNi3C 0.5 、Co3InC 0.75 and ZnNi3C 0.7 A combination of one or more of .

3. The method for synthesizing cyclohexyloxyacetic acid ester according to claim 1, characterized in that: The catalyst is prepared by a preparation method comprising the following steps: 1) adding a precipitant to a mixture of water, a carrier and at least two corresponding active metal salts for precipitation, and obtaining a supported metal oxide precursor after aging, filtering, drying and calcining; 2) performing a reduction carbonization treatment on the supported metal oxide precursor in an atmosphere of synthesis gas to obtain the supported catalyst; the active metal salt is selected from salts of In, Co, Ni or Zn.

4. The method for synthesizing cyclohexyloxyacetic acid ester according to claim 3, characterized in that: The active metal salt is selected from nitrate, sulfate, acetylacetonate or acetate of In, Co, Ni or Zn.

5. The method for synthesizing cyclohexyloxyacetic acid ester according to claim 1, characterized in that: The cyclohexyloxyacetic acid ester is selected from one or more combinations of cyclohexyloxyacetic acid methyl ester, cyclohexyloxyacetic acid ethyl ester, cyclohexyloxyacetic acid allyl ester and cyclohexyloxyacetic acid hexyl ester.

6. The method for synthesizing cyclohexyloxyacetic acid ester according to claim 1, characterized in that: The synthesis method comprises the following steps: 1) adding the phenoxyacetic acid ester and the catalyst into a reaction kettle, and introducing nitrogen into the reaction kettle to replace the air therein; 2) heating the reaction kettle to a reaction temperature, and then introducing hydrogen into the reaction kettle for reaction, and during the reaction process, introducing hydrogen into the reaction kettle continuously or intermittently so that the pressure in the reaction kettle is maintained stable.

7. The method for synthesizing cyclohexyloxyacetic acid ester according to claim 6, characterized in that: In step 1), the mass ratio of the catalyst to phenoxyacetic acid ester is 1:5-1000.

8. The method for synthesizing cyclohexyloxyacetic acid ester according to claim 6, characterized in that: In step 2), the reaction temperature is 100-200°C.

9. The method for synthesizing cyclohexyloxyacetic acid ester according to claim 6, characterized in that: In step 2), the pressure is 0.5-6 MPa.

10. The method for synthesizing cyclohexyloxyacetic acid ester according to claim 6, characterized in that: In step 2), the reaction time is 1 to 36 hours.

11. The method for synthesizing cyclohexyloxyacetic acid ester according to claim 1, characterized in that: The synthesis method comprises the following steps: 1) loading the catalyst into a fixed bed reactor, introducing nitrogen into the fixed bed reactor to replace the air therein; 2) heating the fixed bed reactor to a reaction temperature, and then introducing hydrogen into the fixed bed reactor so that the pressure in the fixed bed reactor rises to the reaction pressure; 3) continuously introducing hydrogen and phenoxyacetic acid ester into the fixed bed reactor for reaction.

12. The method for synthesizing cyclohexyloxyacetic acid ester according to claim 11, characterized in that: In step 2), the reaction temperature is 100-200°C.

13. The method for synthesizing cyclohexyloxyacetic acid ester according to claim 11, characterized in that: In step 2), the reaction pressure is 0.5-6 MPa.

14. The method for synthesizing cyclohexyloxyacetic acid ester according to claim 11, characterized in that: In step 3), the mass space velocity of the phenoxyacetic acid ester is 0.5 to 5 h -1 .

15. The method for synthesizing cyclohexyloxyacetic acid ester according to claim 11, characterized in that: In step 3), the molar ratio of hydrogen to phenoxyacetic acid ester is 3 to 40:1.

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