阅读说明：本技术 一种铃兰醛的制备方法 (Preparation method of lilial ) 是由 郭云峰 桂振友 蔺海政 郭斌 孔令晓 张迪 于 2021-09-16 设计创作，主要内容包括：本发明提供一种制备铃兰醛的方法。所述方法为叔丁基苯和α-甲基丙烯醛在Ti-K(Na)/F-Meso-SiO-(2)非均相催化剂催化下合成得到铃兰醛。本发明所用的催化剂通过F元素对载体的改性,进一步增强了催化剂B酸酸性,同时K和/或Na对Ti金属的掺杂有效提高了Ti金属的催化活性,本发明所用催化剂由于其兼具B酸和L酸位,两种酸性活性中心协同催化,使工艺条件温和、反应时间短、催化剂易于回收利用,也解决了传统催化剂使用后产生大量废酸和固废的问题。(The invention provides a method for preparing lilial. The method is that tert-butyl benzene and alpha-methylacrolein are added in Ti-K (Na)/F-Meso-SiO 2 Synthesizing under the catalysis of a heterogeneous catalyst to obtain the lilial. The catalyst used in the invention further enhances the acidity of the catalyst B by modifying the carrier through the F element, and simultaneously effectively improves the catalytic activity of Ti metal by doping the Ti metal with K and/or Na.)

1. The method for preparing the lilial is characterized in that tert-butyl benzene and alpha-methylacrolein are added into Ti-K (Na)/F-Meso-SiO₂Synthesizing under the catalysis of a heterogeneous catalyst to obtain the lilial.

2. The method of claim 1, wherein the Ti-k (na)/F-Meso-SiO is present in an amount sufficient to reduce the formation of lilial₂The catalyst takes F modified mesoporous silica as a carrier and takes K and/or Na doped Ti metal as an active center;

and/or, the catalyst supports Ti metal under alkaline conditions, preferably at a pH of 8-10, more preferably 8.5-9.0.

3. The method for producing lilial according to claim 1 or 2, characterized in that the step of producing lilial is: adding Ti-K (Na)/F-Meso-SiO to tert-butyl benzene₂The catalyst and alpha-methylacrolein are heated to react to obtain the reaction liquid containing the lilial.

4. The method for producing muguet aldehyde according to claim 3, wherein the content of α -methacrolein in t-butylbenzene is 25 to 40 wt%, preferably 30 to 36 wt%, more preferably 32 to 34 wt%; the Ti-K (Na)/F-Meso-SiO₂The amount of the catalyst is 1-8.0 wt%, preferably 2-6 wt%, more preferably 3-4 wt% of the mass of the tert-butyl benzene;

and/or the reaction temperature is 45-80 ℃, preferably 50-60 ℃, more preferably 52-55 ℃; the reaction time is 1 to 3 hours, preferably 1.5 to 2.0 hours; the pressure is normal pressure.

5. Ti-K (Na)/F-Meso-SiO₂A method for preparing a catalyst for use in the method according to any one of claims 1 to 3, characterized in that the method for preparing a catalyst comprises the steps of:

s1: ti metal loading: putting mesoporous silicon dioxide into water, adding ammonia water to adjust the pH value of a system to be alkaline, and adding Ti salt for loading;

s2: and (3) loading a modification auxiliary agent: adding KF and/or NaF load into the S1 system, removing solvent, drying, and calcining to obtain the target catalyst.

6. The method of claim 5, wherein the mass of the mesoporous silica in S1 in water is 10-30 wt%, preferably 15-20 wt%, more preferably 16-17 wt%;

and/or, the ammonia water of S1 is strong ammonia water, preferably strong ammonia water with the concentration of 26 wt%;

and/or S1 adjusting the pH value of the system to 8.0-10.0, preferably 8.5-9.0;

and/or, S1 the Ti salt is titanium tetrachloride and/or titanium nitrate, preferably titanium tetrachloride;

preferably, the Ti salt is TiO₂The amount is 1-5 wt%, preferably 1.5-3.0 wt%, more preferably 1.8-2.0 wt% of mesoporous silica;

and/or the temperature of S1 is 10-40 ℃, preferably 15-30 ℃, more preferably 20-22 ℃; the loading time is 0.5-3h, preferably 2.0-2.5 h.

7. The method for preparing the catalyst according to claim 3, wherein the amount of KF and/or NaF in S2 is 0.1-0.6 wt%, preferably 0.2-0.3 wt% of the amount of mesoporous silica;

and/or the time for loading the modification auxiliary agent of S2 is 2-5h, preferably 3-4 h;

and/or S2 placing the solution in a rotary evaporation bottle to quickly evaporate the solvent by high-temperature reduced pressure distillation and further performing rotary evaporation drying;

preferably, the temperature of the reduced pressure distillation is 100-150 ℃, preferably 130-140 ℃, and the vacuum degree is 20-50kPaA, preferably 30-35 kPaA; the drying time is 0.5-2.0h, preferably 1.0-1.5 h;

and/or the roasting temperature of S2 is 400-600 ℃, preferably 450-500 ℃; the roasting time is 2-6h, preferably 3-4 h.

8. A lilial produced by the method for producing a lilial according to any one of claims 1 to 3, or catalytically produced by the catalyst obtained by the method for producing a catalyst according to any one of claims 4 to 7.

Technical Field

The invention belongs to the field of organic synthesis, and particularly relates to a preparation method of lilial.

Background

Lilial (C)₁₄H₂₀O) has the fragrance of lily and lily, the fragrance is soft and fresh, the fragrance is lasting, and the lily aldehyde is a pure artificially synthesized monomer spice and is not found in the nature at present. The preparation of the traditional convallaria majalis essence needs to use a large amount of hydroxycitronellal, convallaldehyde, lyral,Congol aldehyde, lily of the valley pyran and the like. With the limitation of IFRA on the dosage of hydroxycitronellal, the use of lyral is forbidden by European Union due to its allergenicity, and the market promotion of the production capacity is slow due to the late appearance of lilac pyrane, so that lilac aldehyde becomes the main perfume for blending lilac essence at present, and the annual demand of lilac essence in the market is more than twenty-thousand tons at present. The molecular structure of lilial is as follows:

although the prior methods for synthesizing the lilial have a lot of problems and defects, the process technology has a few problems and defects, so that the research of a process route which has the advantages of short steps, simple operation, high yield, low cost, environmental friendliness and suitability for industrial production is very necessary.

The existing synthetic routes of the lilial mainly comprise the following steps: the first method is to carry out aldol condensation reaction on benzaldehyde and n-propionaldehyde and then carry out hydrogenation reaction to obtain the product convallaldehyde, and the method has high yield, but the cost of the route is higher due to the relatively higher price of the p-tert-butyl benzaldehyde. The second one is that benzaldehyde and propionaldehyde are used as raw materials, a-methyl cinnamic aldehyde is generated by condensation in dilute alkali liquor, aldehyde is hydrogenated into 2-methyl phenylpropyl alcohol by a catalyst, then tert-butyl chloride or isobutene is used for alkylation reaction, and finally the product is added into a mixture consisting of copper chromite and liquid wax, and the mixture is heated, dehydrogenated and fractionated under reduced pressure to obtain the lilac aldehyde. The third one is that tert-butyl benzene and alpha-methylacrolein are used as raw materials to react at low temperature to prepare lilac aldehyde (see the following formula specifically), the catalyst used at present is a compound of titanium tetrachloride and boron trifluoride diethyl etherate, the method only has one-step reaction to synthesize lilac aldehyde, the obtained product has high purity and good quality, but the current route has the defects of low yield, a large amount of Lewis acid is used as the catalyst in the reaction, a large amount of waste acid is generated in the post-treatment process, and the cost for treating three wastes is high, so before the development of a novel catalyst, the third route can not realize industrialization temporarily.

In view of the foregoing, a more efficient and green preparation method is needed to improve production efficiency. Based on the advantages and disadvantages of the three process routes, the third process route has the advantages of short process flow, less side reactions and high product purity, and has great potential for industrialization in the future.

Disclosure of Invention

The invention aims to provide a preparation method of lilial, which has the advantages of mild process conditions (low temperature and normal pressure), short reaction time, easy recycling of a catalyst and the like. Under the optimal condition, the method can achieve the reaction conversion rate of more than 98.0 percent (calculated by alpha-methylacrolein), the yield of more than 97 percent, the reaction temperature of 52-55 ℃ and the reaction pressure of normal pressure.

In order to achieve the above purpose, the technical scheme provided by the invention is as follows:

a process for preparing lilial from tert-butyl benzene and alpha-methylacrolein in Ti-K (Na)/F-Meso-SiO₂Synthesizing under the catalysis of a heterogeneous catalyst to obtain the lilial.

In the present invention, the Ti-K (Na)/F-Meso-SiO₂The catalyst takes F modified mesoporous silica as a carrier and takes K and/or Na doped Ti metal as an active center.

In the present invention, the catalyst supports Ti metal under alkaline conditions, preferably at a pH of 8 to 10, more preferably 8.5 to 9.0. Ammonia water is used for adjusting the pH value of the system to 8-10, and on the one hand, SiO is used under the pH condition₂The surface is negatively charged and can be used to provide sites for subsequent Ti metal ion loading, and on the other hand, is through NH₃Forming a water-soluble complex by coordination with Ti ions to avoid precipitation of the Ti ions under alkaline conditions

In the invention, the preparation method of the lilial comprises the following steps: adding Ti-K (Na)/F-Meso-SiO to tert-butyl benzene₂The catalyst and alpha-methylacrolein are heated to react to obtain the reaction liquid containing the lilial.

In the present invention, the content of the α -methacrolein in the tert-butyl benzene is 25 to 40 wt%, preferably 30 to 36 wt%, more preferably 32 to 34 wt%; the Ti-K (Na)/F-Meso-SiO₂The amount of the catalyst is 1-8.0 wt%, preferably 2-6 wt%, more preferably 3-4 wt% of the mass of the tert-butyl benzene; the reaction temperature is 45-80 ℃, preferably 50-60 ℃, and more preferably 52-55 ℃; the reaction time is 1 to 3 hours, preferably 1.5 to 2.0 hours; the pressure is normal pressure.

Ti-K (Na)/F-Meso-SiO used in the invention₂The catalyst has rich mesoporous pore canals, provides sufficient reaction space for catalytic reaction, and is characterized in that: by utilizing the characteristic that the isoelectric point of the surface of the silicon dioxide is about 8, the silicon hydroxyl-Si-OH on the surface of the silicon dioxide can be deprotonated to be changed into negatively charged-Si-O after the pH of the system is adjusted to be 8-10^-Thus, the charge effect provided by the positively charged metal cation is exactly what we know then is the metal ion Ti⁴⁺Precipitation occurs under alkaline conditions, and Ti is avoided by ammonia complexation⁴⁺Thereby achieving Ti⁴⁺High-dispersion loading of metals by charge action under alkaline conditions, followed by addition of KF and/or NaF, negatively charged F^-The carrier can be loaded on the carrier through the action of charges to modify the carrier, so that the acidity of the B acid of the carrier is enhanced, the number of acid sites of the B acid is increased, the Ti metal is doped by K/Na ions, the activity of the Ti metal is improved, the loss of metal components can be avoided through the rapid evaporation of a solvent, the effective load is realized, and the Ti-K (Na)/F-Meso-SiO with high dispersion and high activity is obtained after roasting₂A catalyst. Because the catalyst has rich B acid sites and L acid sites, the two acid active centers are effectively cooperated, and the activity of the catalyst is obviously improved.

Another object of the inventionIn order to provide Ti-K (Na)/F-Meso-SiO₂A method for preparing a catalyst.

In the present invention, the Ti-K (Na)/F-Meso-SiO₂The preparation method of the catalyst comprises the following steps:

s1: ti metal loading: putting mesoporous silicon dioxide into water, adding ammonia water to adjust the pH value of a system to be alkaline, and adding Ti salt for loading;

s2: and (3) loading a modification auxiliary agent: adding KF and/or NaF load into the S1 system, removing solvent, drying, and calcining to obtain the target catalyst.

In the invention, the ammonia water added in the S1 has two functions, namely, the ammonia coordination of Ti ions can be realized, the phenomenon that Ti precipitates too early under an alkaline condition to cause uneven metal dispersion is avoided, and the electroneutrality of the surface of a silicon oxide pore channel can be changed, so that silicon hydroxyl on the surface of the silicon oxide pore channel is deprotonated and negatively charged and is Ti (NH) with positive charge₃)₂ ⁴⁺The ions lay a foundation for realizing high dispersion load of Ti through the action of charges.

In the present invention, the mass of the mesoporous silica in S1 in water is 10 to 30 wt%, preferably 15 to 20 wt%, more preferably 16 to 17 wt%.

In the present invention, the aqueous ammonia described in S1 is concentrated aqueous ammonia, preferably concentrated aqueous ammonia having a concentration of 26 wt%.

In the invention, S1 is used for adjusting the pH value of the system to 8.0-10.0, preferably 8.5-9.0.

In the invention, the Ti salt in S1 is titanium tetrachloride and/or titanium nitrate, preferably titanium tetrachloride; preferably, the Ti salt is TiO₂The amount is 1-5 wt%, preferably 1.5-3.0 wt%, and more preferably 1.8-2.0 wt% of the mesoporous silica.

In the invention, the temperature of S1 is 10-40 ℃, preferably 15-30 ℃, and more preferably 20-22 ℃; the loading time is 0.5-3h, preferably 2.0-2.5 h.

In the present invention, the amount of KF and/or NaF in S2 is 0.1 to 0.6 wt%, preferably 0.2 to 0.3 wt%, of the amount of mesoporous silica.

In the invention, the time for loading the modification auxiliary agent S2 is 2-5h, preferably 3-4 h.

In the invention, S2 is to put the solution into a rotary evaporation bottle to quickly evaporate the solvent by high-temperature reduced pressure distillation and further to carry out rotary evaporation drying; preferably, the temperature of the reduced pressure distillation is 100-150 ℃, preferably 130-140 ℃, and the vacuum degree is 20-50kPaA, preferably 30-35 kPaA; the drying time is 0.5-2.0h, preferably 1.0-1.5 h.

In the invention, the roasting temperature of S2 is 400-600 ℃, preferably 450-500 ℃; the roasting time is 2-6h, preferably 3-4 h.

The invention adopts F modified mesoporous SiO₂Ti-K (Na)/F-Meso-SiO prepared by one-pot method by taking metal Ti doped with K and/or Na as active center as carrier₂The heterogeneous catalyst is used for efficiently catalyzing tert-butyl benzene and alpha-methylacrolein to prepare the lilial under the low-temperature condition. Compared with the traditional catalyst for preparing the lilial by the method, the catalyst used by the invention further enhances the acid acidity of the catalyst B by modifying the carrier by the F element, and simultaneously, the doping of the K and/or Na to the Ti metal effectively improves the catalytic activity of the Ti metal. In addition, the catalyst used in the method can be separated and recycled through filtration, so that the problems of a large amount of waste acid and solid waste generated after the traditional catalyst is used are solved, and the three-waste treatment cost is greatly reduced.

It is still another object of the present invention to provide lilial.

The lilial is prepared by the method for preparing the lilial or is prepared by the catalyst obtained by the method for preparing the catalyst.

Compared with the prior art, the invention has the advantages that:

(1) the process conditions are mild (the temperature is low and is only 52-55 ℃, the pressure is normal), the reaction time is short, the catalyst is easy to recycle, the used catalyst can be separated and recycled through filtration, the problem that a large amount of waste acid and solid waste are generated after the traditional catalyst is used is solved, and the three-waste treatment cost is greatly reduced.

(2) Under the optimal condition, the reaction conversion rate can reach more than 98.0 percent by the alpha-methylacrolein, and the yield reaches more than 97 percent.

Detailed description of the invention

The following examples are not intended to limit the scope of the present invention, and modifications and equivalents may be made thereto without departing from the spirit and scope of the present invention, which is defined in the appended claims.

The raw materials used in the examples are conventional in the art, the purity specification used is analytical or chemical purity, and the raw material source information:

mesoporous silica, alpha-methylacrolein, p-tert-butylbenzene, concentrated ammonia water, titanium tetrachloride, titanium nitrate, potassium fluoride and sodium fluoride are all purchased from Shanghai Allantin Biotech Co., Ltd.

The following test methods were used:

the lilial is analyzed by a GC-9800 chromatograph under the chromatographic conditions that: a weakly polar chromatography column; the initial temperature is 100 ℃, the temperature is kept for 2min, the temperature is programmed to 260 ℃ at the speed of 10 ℃/min, and the temperature is kept for 5 min; the temperature of the gasification chamber is 300 ℃, and the temperature of the detection chamber is 300 ℃; FID detection; the sample size was 0.2. mu.l.

Example 1

1) Preparation of Ti-K (Na)/F-Meso-SiO₂Catalyst:

to 200g of deionized water was added 32g (16 wt%) of mesoporous silica Meso-SiO₂Concentrated ammonia (26 wt%) was added dropwise to adjust the pH of the system to 9.0, and 1.37g of titanium tetrachloride (Meso-SiO) was added₂1.8% by mass with TiO₂Gauge) was added, the temperature was raised to 21 ℃ and stirred for 2.0 hours, and 0.064g of NaF (Meso-SiO) was added₂0.2 wt%) of the weight, continuously stirring for 3h, then placing the solution in a rotary evaporation bottle, adjusting the temperature to 130 ℃, evaporating the solvent to dryness under the pressure of 30kPa (absolute pressure), then continuously drying by rotary evaporation for 1.5h, finally taking out the solid, placing the solid in a muffle furnace, and roasting for 4h at the temperature of 500 ℃ to obtain the Ti-Na/F-Meso-SiO₂A catalyst.

2) Preparation of lilial

To 200g of t-butylbenzene was added 64g of a-methacrolein (32 wt%), followed by 6.0g of Ti-Na/F-Meso-SiO₂(3.0wt％)And (3) placing the catalyst in a 0.5L reactor, raising the reaction temperature to 55 ℃, maintaining the reaction pressure at normal pressure, reacting for 1.5h, and analyzing the product obtained after the reaction to calculate the conversion rate to be 98.3% and the yield to be 97.3%.

3) Evaluation of catalyst:

repeatedly applying the catalyst according to the step 2), wherein the conversion rate and yield data after different application times are as follows:

number of times of catalyst application	Conversion rate of reaction/%)	Yield/%
			20	98.1	97.1
40	97.9	96.9
			60	97.8	96.8

As can be seen from the above table, the catalyst still has high catalytic activity after being reused for many times.

Example 2

1) Preparation of Ti-K/F-Meso-SiO₂Catalyst:

to 200g of deionized water was added 34g (17 wt%) of mesoporous silica Meso-SiO₂Adding concentrated ammonia (26 wt%) dropwise to adjust system pH to 8.5, adding 2.52g titanium nitrate (Meso-SiO)₂2.0 wt% of the mass as TiO₂Gauge) was added, the temperature was raised to 20 ℃ and stirred for 2.5 hours, 0.102g of KF (Meso-SiO) was added₂0.3 wt%) of the weight, continuously stirring for 4h, then placing the solution in a rotary evaporation bottle, adjusting the temperature to 140 ℃, evaporating the solvent to dryness under the pressure of 35kPa (absolute pressure), then continuously drying by rotary evaporation for 1.0h, finally taking out the solid, placing the solid in a muffle furnace, and roasting for 3h at the temperature of 450 ℃ to obtain the Ti-K/F-Meso-SiO₂A catalyst.

2) Preparing lilial:

to 200g of t-butylbenzene was added 68g of alpha-methacrolein (34 wt%), followed by 8.0g of Ti-K/F-Meso-SiO₂(4.0 wt%) catalyst, placing in a 0.5L reactor, raising reaction temperature to 52 deg.C, maintaining reaction pressure at normal pressure, reacting for 2.0h, and analyzing the obtained product after reaction to obtain reaction conversion rate of 98.1% and yield of 97.1%.

Example 3

1) Preparation of Ti-Na/F-Meso-SiO₂Catalyst:

20g (10 wt%) of mesoporous silica Meso-SiO was added to 200g of deionized water₂Adding concentrated ammonia (26 wt%) dropwise to adjust system pH to 8, adding 2.37g titanium tetrachloride (Meso-SiO)₂5.0 wt% of the mass as TiO₂Gauge) is added, the temperature is raised to 30 ℃, the mixture is stirred for 0.5h, and 0.12g of NaF (Meso-SiO) is added₂0.6 wt%) of the weight, continuously stirring for 2h, then placing the solution in a rotary evaporation bottle, adjusting the temperature to 150 ℃, drying the solvent by distillation under the pressure of 20kPa (absolute pressure), then continuously drying by rotary evaporation for 0.5h, finally taking out the solid, placing the solid in a muffle furnace, and roasting for 6h at the temperature of 400 ℃ to obtain the Ti-Na/F-Meso-SiO₂A catalyst.

2) Preparing lilial:

to 200g of t-butylbenzene was added 50g of alpha-methacrolein (25 wt%), followed by 4.0g of Ti-Na/F-Meso-SiO₂(2.0 wt%) catalyst, placing in a 0.5L reactor, raising reaction temperature to 80 deg.C, maintaining reaction pressure at normal pressure, reacting for 1.0h to obtain product, analyzing and calculating reaction conversion rate to 95.6%, and collectingThe rate was 94.6%.

Example 4

1) Preparation of Ti-K/F-Meso-SiO₂Catalyst:

40g (20 wt%) of mesoporous silica Meso-SiO was added to 200g of deionized water₂Adding concentrated ammonia water (26 wt%) dropwise to adjust system pH to 10.0, adding 1.48g titanium nitrate (Meso-SiO)₂1.0 wt% of the mass as TiO₂Gauge) was added, the mixture was heated to 10 ℃ and stirred for 3.0 hours, and 0.04g of KF (Meso-SiO) was added₂0.1 wt%) of the weight, continuously stirring for 5h, then placing the solution in a rotary evaporation bottle, adjusting the temperature to 100 ℃, evaporating the solvent to dryness under the pressure of 45kPa (absolute pressure), then continuously drying by rotary evaporation for 2.0h, finally taking out the solid, placing the solid in a muffle furnace, and roasting for 2h at 550 ℃ to obtain the Ti-K/F-Meso-SiO₂A catalyst.

2) Preparing lilial:

to 200g of t-butylbenzene was added 72g of alpha-methacrolein (36 wt%), followed by 16.0g of Ti-K/F-Meso-SiO₂(8.0 wt%) catalyst, placing in a 0.5L reactor, raising the reaction temperature to 45 deg.C, maintaining the reaction pressure at normal pressure, reacting for 3.0h, and analyzing the obtained product after reaction to obtain a reaction conversion rate of 90.1% and a yield of 89.2%.

Example 5

1) Preparation of Ti-Na/F-Meso-SiO₂Catalyst:

to 200g of deionized water, 60g (30 wt%) of mesoporous silica Meso-SiO was added₂Concentrated ammonia (26 wt%) was added dropwise to adjust the pH of the system to 9.5, and 4.27g of titanium tetrachloride (Meso-SiO) was added₂3.0 wt% of the mass as TiO₂Gauge) was added, the temperature was raised to 40 ℃ and stirred for 2.0h, 0.24g of NaF (Meso-SiO) was added₂0.4 wt%) of the weight, continuously stirring for 4h, then placing the solution in a rotary evaporation bottle, adjusting the temperature to 120 ℃, evaporating the solvent to dryness under the pressure of 50kPa (absolute pressure), then continuously drying by rotary evaporation for 2.0h, finally taking out the solid, placing the solid in a muffle furnace, and roasting for 5h at the temperature of 600 ℃ to obtain the Ti-Na/F-Meso-SiO₂A catalyst.

2) Preparing lilial:

to 200g of tert-butyl benzene80g of alpha-methacrolein (40 wt%) was added, followed by 12.0g of Ti-K/F-Meso-SiO₂(6.0 wt%) of catalyst, placing the mixture in a 0.5L reactor, raising the reaction temperature to 60 ℃, maintaining the reaction pressure at normal pressure, reacting for 1.0h, and analyzing the obtained product after the reaction to calculate that the reaction conversion rate is 96.4% and the yield is 95.4%.

Example 6

1) Preparation of Ti-K/F-Meso-SiO₂Catalyst:

to 200g of deionized water was added 30g (15 wt%) of mesoporous silica Meso-SiO₂Adding concentrated ammonia (26 wt%) dropwise to adjust system pH to 8.0, adding 1.67g titanium nitrate (Meso-SiO)₂1.5% by mass with TiO₂Gauge) at 15 deg.C, stirring for 2.0h, adding 0.06g KF (Meso-SiO)₂0.4 wt%) of the weight, continuously stirring for 3h, then placing the solution in a rotary evaporation bottle, adjusting the temperature to 110 ℃, drying the solvent by distillation under the pressure of 25kPa (absolute pressure), then continuously drying by rotary evaporation for 0.5h, finally taking out the solid, placing the solid in a muffle furnace, and roasting for 2h at 520 ℃ to obtain the Ti-K/F-Meso-SiO₂A catalyst.

2) Preparing lilial:

to 200g of t-butylbenzene was added 60g of alpha-methacrolein (30 wt%), followed by 2.0g of Ti-K/F-Meso-SiO₂(1.0 wt%) catalyst, placing in a 0.5L reactor, raising reaction temperature to 70 deg.C, maintaining reaction pressure at normal pressure, reacting for 3.0h, and analyzing the obtained product after reaction to obtain reaction conversion rate of 97.0% and yield of 96.0%.

Comparative example 1

The only difference compared to example 1 was the replacement of the catalyst with the equivalent mass of the prior art conventional catalyst titanium tetrachloride.

The above catalyst was used to prepare lilial, and the other procedures were the same as in example 1. The product obtained after the reaction was analyzed, and the reaction conversion rate calculated by the analysis was 65%, and the yield of lilial was 54%.

Comparative example 2

Compared with example 1, the difference is only that NaF or KF is not added in the process of preparing the catalyst, and the catalyst is not used.

Bellaldehyde was prepared using equal mass of the above catalyst and the other procedure was the same as in example 1. The reaction conversion rate of the product obtained after the reaction is calculated to be 81 percent and the yield of the lilial is 72 percent after the product is analyzed.

Comparative example 3

The only difference from example 1 is that example 1 is used to prepare Ti-K/F-Meso-SiO₂In the catalyst process, the pH of the reaction system is not adjusted.

The other procedures were the same as in example 1. The reaction conversion rate of the product obtained after the reaction is calculated to be 79 percent and the yield of the lilial is 56 percent after the product is analyzed.

The results of the above examples and comparative examples show that the preparation method of lilial of the present invention has mild process conditions, short reaction time, easy catalyst recycling, and solves the problem of large amount of waste acid and solid waste generated after the traditional catalyst is used.