阅读说明：本技术 一种利用固体酸催化剂制备叔丁基甘油醚的方法 (Method for preparing tert-butyl glyceryl ether by using solid acid catalyst ) 是由 肖国民 刘雪萍 高李璟 韩菲 杨素 张进 魏瑞平 于 2021-08-11 设计创作，主要内容包括：本发明公开了一种利用固体酸催化剂制备叔丁基甘油醚的方法,属于有机合成技术领域,以甘油和叔丁醇为原料,以负载型磷钨酸固体酸为催化剂,在密闭耐压的反应器中一定温度下反应一段时间后,产物经常规分离得到叔丁基甘油醚,甘油转化率为76.3-93.2％,三叔丁基甘油醚(TTBG)的选择性为5.5-11.3％,二叔丁基甘油醚(DTBG)的选择性为30.1-45.7％。其中负载型磷钨酸固体酸催化剂以磷钨酸为活性组分,通过将载体与磷钨酸按一定质量比采用等体积浸渍法浸渍9-12h,然后烘干,于250-400℃焙烧2-4h得到。本发明通过筛选最优反应条件并利用磷钨酸改性催化剂,能够有效提高甘油转化生成叔丁基甘油醚时甘油的转化率和对多取代叔丁基甘油醚的选择性,且催化剂能够多次循环使用。(The invention discloses a method for preparing tert-butyl glyceryl ether by using a solid acid catalyst, which belongs to the technical field of organic synthesis, wherein glycerol and tert-butyl alcohol are used as raw materials, supported phosphotungstic acid solid acid is used as a catalyst, after reaction is carried out for a period of time at a certain temperature in a closed pressure-resistant reactor, the product is subjected to conventional separation to obtain the tert-butyl glyceryl ether, the glycerol conversion rate is 76.3-93.2%, the selectivity of tri-tert-butyl glyceryl ether (TTBG) is 5.5-11.3%, and the selectivity of di-tert-butyl glyceryl ether (DTBG) is 30.1-45.7%. The supported phosphotungstic acid solid acid catalyst is prepared by using phosphotungstic acid as an active component, impregnating a carrier and the phosphotungstic acid for 9-12h by an isometric impregnation method according to a certain mass ratio, drying, and roasting at the temperature of 250-400 ℃ for 2-4 h. According to the invention, through screening the optimal reaction conditions and utilizing the phosphotungstic acid modified catalyst, the conversion rate of glycerol and the selectivity of polysubstituted tert-butyl glyceryl ether during the conversion of glycerol into tert-butyl glyceryl ether can be effectively improved, and the catalyst can be recycled for multiple times.)

1. A method for preparing tert-butyl glyceryl ether by using a solid acid catalyst is characterized by comprising the following steps: the method comprises the following steps:

(1) reacting glycerol and tert-butyl alcohol with the mass ratio of substances of 1: 4-1: 12 and a solid acid catalyst accounting for 1-20% of the mass ratio of the glycerol in a closed pressure-resistant reactor to obtain a product;

(2) and (2) separating the product obtained in the step (1) to obtain tert-butyl glyceryl ether.

2. The method for preparing tert-butyl glyceryl ether by using a solid acid catalyst as claimed in claim 1, wherein: in the step (1), the concrete steps are as follows: adding glycerol, tert-butyl alcohol and a supported phosphotungstic acid solid acid catalyst into a high-pressure reaction kettle by using N₂Purging for more than three times, and removing air from the high-pressure reaction kettle to perform reaction.

3. The method for preparing tert-butyl glyceryl ether by using a solid acid catalyst as claimed in claim 1, wherein: in the step (1), the reaction conditions are as follows: reacting for 8-12 h at the autogenous pressure of 0-2 MPa and the temperature of 80-120 ℃.

4. The method for preparing tert-butyl glyceryl ether by using a solid acid catalyst as claimed in claim 1, wherein: in the step (2), the product comprises tri-tert-butyl glycerol ether and di-tert-butyl glycerol ether, wherein the selectivity of the tri-tert-butyl glycerol ether is 5.5-11.3%, and the selectivity of the di-tert-butyl glycerol ether is 30.1-45.7%.

5. The method for preparing tert-butyl glyceryl ether by using a solid acid catalyst as claimed in claim 1, wherein: in the step (1), the solid acid catalyst is a supported phosphotungstic acid solid acid catalyst, the supported phosphotungstic acid solid acid catalyst takes phosphotungstic acid as an active component, and the supported phosphotungstic acid solid acid catalyst is obtained by adopting an isometric impregnation method for a carrier and phosphotungstic acid.

6. The method for preparing tert-butyl glyceryl ether by using a solid acid catalyst as claimed in claim 5, wherein: the carrier is one of zirconium dioxide, tin dioxide or silicon dioxide.

7. The method for preparing tert-butyl glyceryl ether by using a solid acid catalyst as claimed in claim 5, wherein: the supported phosphotungstic acid solid acid catalyst is obtained by the following method: adding the carrier and phosphotungstic acid into water, and stirring at room temperature; and standing, drying and roasting the stirred material in sequence to obtain the supported phosphotungstic acid solid acid catalyst.

8. The method for preparing tert-butyl glyceryl ether by using a solid acid catalyst as claimed in claim 5, wherein: the mass ratio of the addition amount of the carrier to the phosphotungstic acid is 1: 0.1-0.3; the volume of the corresponding deionized water was calculated from its water absorption for each 1g of carrier.

9. The method for preparing tert-butyl glyceryl ether by using a solid acid catalyst as claimed in claim 7, wherein: the catalyst calcination temperature is 250-400 ℃, and the calcination time is 2-4 h.

Technical Field

The invention belongs to the technical field of organic synthesis, and particularly relates to a method for preparing tert-butyl glyceryl ether by using a solid acid catalyst.

Background

With the increasing energy crisis and environmental pollution, biodiesel, as a renewable resource, has been researched and produced by more and more countries. However, for every 1 ton of biodiesel produced, 0.1 ton of glycerol is produced as a by-product, and it is therefore necessary to convert it into value-added chemicals by means of appropriate techniques. The development and utilization of the biodiesel byproduct glycerol are improved, and the comprehensive utilization rate and the economical efficiency of the whole process can be improved.

Glyceryl ethers are currently known as valuable alternative fuel additives. The di-substituted tert-butyl glyceryl ether and the tri-substituted tert-butyl glyceryl ether are suitable additives mixed into diesel oil and biodiesel, because the di-substituted tert-butyl glyceryl ether and the tri-substituted tert-butyl glyceryl ether belong to nonpolar substances, have good solubility and low viscosity, and can be mixed and dissolved with the nonpolar substances such as diesel oil and the like. Meanwhile, the oxygen content of the disubstituted tert-butyl glycerol ether and the oxygen content of the trisubstituted tert-butyl glycerol ether are respectively 23.5 percent and 18.5 percent, which are far higher than the oxygen content of 11 percent of the biodiesel. The two can be used as fuel additives, the emission of particulate matters, carbon monoxide and hydrocarbon can be greatly reduced, and the performance of the engine at low temperature can be improved. Therefore, the method for efficiently producing the polysubstituted tert-butyl glycerol ether has great potential in solving the problem of excess glycerol. The etherification reaction of glycerol and tert-butyl alcohol can obtain tert-butyl glycerol ether mixture containing mono-tert-butyl glycerol ether, di-tert-butyl glycerol ether and tri-tert-butyl glycerol ether.

There is currently active research on the conversion of glycerol to tert-butyl glycerol ether. The patent with application number 201310643671.5 discloses a preparation method of a binuclear acidic ionic liquid immobilized SBA-15 molecular sieve catalyst for synthesizing tert-butyl glyceryl ether, which can obtain about 70% of glycerin conversion rate and 40% of multi-substituted tert-butyl glyceryl ether selectivity; however, the method has complicated steps for preparing the catalyst, and increases the complexity of the reaction and the reaction cost. Cristian Miranda et al (Cristian Miranda et al. sulfonated graphene acid catalysts for the glycerol validation [ J ]. Applied Catalysis A, General,2019,580: 167-.

In the existing method, when the tert-butyl glyceryl ether is generated by converting glycerol, the preparation process of the used catalyst is complex, the raw materials are expensive, the glycerol conversion rate is low, the selectivity of the polysubstituted tert-butyl glyceryl ether is low, and in addition, the reaction for generating the tert-butyl glyceryl ether by converting glycerol is carried out at high temperature and high pressure, so that the skeleton structure of the existing catalyst is easy to collapse, the catalyst cannot be recycled for multiple times, and the recovery rate is low.

Disclosure of Invention

The purpose of the invention is as follows: the invention provides a method for preparing tert-butyl glyceryl ether by using a solid acid catalyst, aiming at the problems of low glycerol conversion rate, low selectivity of multi-substituted tert-butyl glyceryl ether and low recovery rate of a reaction catalyst at high temperature and high pressure when glycerol is converted to generate tert-butyl glyceryl ether in the prior art.

The technical scheme is as follows: a method for preparing tert-butyl glyceryl ether by using a solid acid catalyst comprises the following steps:

(1) reacting glycerol and tert-butyl alcohol with the mass ratio of substances of 1: 4-1: 12 and a solid acid catalyst accounting for 1-20% of the mass ratio of the glycerol in a closed pressure-resistant reactor to obtain a product;

(2) and (2) separating the product obtained in the step (1) to obtain tert-butyl glyceryl ether.

Further, in the step (1), the specific steps are as follows: adding glycerol, tert-butyl alcohol and a supported phosphotungstic acid solid acid catalyst into a high-pressure reaction kettle by using N₂Purging for more than three times, and removing air from the high-pressure reaction kettle to perform reaction.

Further, in the step (1), the reaction conditions are as follows: reacting for 8-12 h at the autogenous pressure of 0-2 MPa and the temperature of 80-120 ℃.

Further, in the step (2), the product comprises tri-tert-butyl glycerol ether, di-tert-butyl glycerol ether and glycerol, wherein the selectivity of the tri-tert-butyl glycerol ether is 5.5-11.3%, and the selectivity of the di-tert-butyl glycerol ether is 30.1-45.7%.

Further, in the step (1), the solid acid catalyst is a supported phosphotungstic acid solid acid catalyst, the supported phosphotungstic acid solid acid catalyst takes phosphotungstic acid as an active component, and the supported phosphotungstic acid solid acid catalyst is obtained by using an isometric impregnation method for a carrier and phosphotungstic acid.

Further, the carrier is one of zirconium dioxide, tin dioxide or silicon dioxide.

Further, the supported phosphotungstic acid solid acid catalyst is obtained by the following method: adding the carrier and phosphotungstic acid into water, and stirring at room temperature; and standing, drying and roasting the stirred material in sequence to obtain the supported phosphotungstic acid solid acid catalyst.

Further, the adding mass ratio of the carrier to the phosphotungstic acid is 1: 0.1-0.3; the volume of the corresponding deionized water was calculated from its water absorption for each 1g of carrier.

Furthermore, the calcination temperature of the catalyst is 250-400 ℃, and the calcination time is 2-4 h.

Has the advantages that: by selecting appropriate reaction substrates, the need for solvents (i.e., dioxane, dimethyl sulfoxide) and the limitations of mass transfer phenomena in the reaction system are avoided. When glycerol is converted to tert-butyl glyceryl etherThe acid sites have higher requirements, and the proportion of the acid sites on the surface of the carrier can be effectively adjusted by loading phosphotungstic acid on the surface of the oxide, so that the etherification reaction can be effectively promoted, and the conversion rate of glycerol and the selectivity of the polysubstituted tert-butyl glyceryl ether are greatly increased; in addition, the modified supported catalyst has stable structure and still has good catalytic effect after being recycled for many times,the economy of the preparation process is improved.

Detailed Description

The technical solution of the present invention is further described with reference to the following specific embodiments.

A method for preparing tert-butyl glyceryl ether by using a solid acid catalyst comprises the following steps:

(1) reacting glycerol and tert-butyl alcohol with the mass ratio of 1: 4-1: 12 and a supported phosphotungstic acid solid acid catalyst accounting for 1-20% of the mass ratio of the glycerol in a closed pressure-resistant reactor to obtain a product;

(2) and (2) separating the product obtained in the step (1) to obtain tert-butyl glyceryl ether.

In the step (1), adding the reaction materials and the supported phosphotungstic acid solid acid catalyst into a 100mL stainless steel high-pressure reaction kettle, and using N₂Purging the high-pressure reaction kettle for three times to remove air, and reacting at the autogenous pressure of 0-2 MPa, the temperature of 80-120 ℃ and the time of 8-12 h.

In the step (2), the product is separated conventionally to obtain tert-butyl glyceryl ether. The conversion rate of glycerol is 76.3-93.2%, the selectivity of tri-tert-butyl glycerol ether (TTBG) is 5.5-11.3%, and the selectivity of di-tert-butyl glycerol ether (DTBG) is 30.1-45.7%.

In the step (1), the supported phosphotungstic acid solid acid catalyst takes phosphotungstic acid as an active component, and is obtained by adopting an isometric impregnation method for a carrier and phosphotungstic acid according to a certain mass ratio. Wherein, the carrier is one of zirconium dioxide, tin dioxide or silicon dioxide.

The preparation method of the supported phosphotungstic acid solid acid catalyst comprises the following steps: adding the carrier and phosphotungstic acid into water, and stirring at room temperature; and standing, drying and roasting the stirred materials in sequence to obtain the required catalyst.

The adding mass ratio of the carrier to the phosphotungstic acid is 1: 0.1-0.3; the volume of the corresponding deionized water was calculated from its water absorption for each 1g of carrier.

The roasting temperature of the catalyst is 250-400 ℃, and the roasting time is 2-4 h.

Example 1

The preparation method of the supported phosphotungstic acid solid acid catalyst comprises the following steps:

(1) pretreating the carrier: ZrO 2 is mixed with₂Placing the powder in a muffle furnace, roasting for 2 hours at 400 ℃, and removing impurities in the powder to improve the purity of the carrier;

(2) 5g of the calcined ZrO were taken₂Adding 0.500g of phosphotungstic acid into 1.5mL of deionized water, and stirring for 1h at normal temperature; loading of phosphotungstic acid to ZrO by stirring₂A surface;

(3) standing the material obtained in the step (2) at normal temperature for 8h to completely impregnate the active component, and then drying in a drying oven at 110 ℃ for 12h to completely remove the water;

(4) roasting the dried solid substance in air at 250 ℃ for 4h to obtain a catalyst with 10 wt% of theoretical loading capacity of phosphotungstic acid, which is recorded as (10) HPW/ZrO₂。

The (10) HPW/ZrO prepared in example 1₂Application of the catalyst in preparation of tert-butyl glyceryl ether by catalysis of glycerol:

4.144g of glycerol, 33.354g of tert-butanol and 0.414g of (10) HPW/ZrO₂Adding the catalyst into a 100mL stainless steel high-pressure reaction kettle, and adding N₂Repeatedly purging the reaction kettle for 3 times to remove air, reacting for 11h at 100 ℃, taking a small amount of reaction solution after the reaction is finished, and measuring the conversion rate of the glycerol to be 74.05 percent and the selectivity of the polysubstituted tert-butyl glycerol ether to be 42.32 percent.

Reacting the (10) HPW/ZrO₂The catalyst is recovered after centrifugation, washing, drying and roasting, is continuously used as the catalyst to be applied to the reaction for preparing the tert-butyl glyceryl ether by catalyzing the glycerol, and a small amount of reaction solution is taken after repeated recovery and repeated application for 4 times, and the conversion rate of the glycerol is determined to be 65.14%. The modified supported catalyst still has good catalytic effect after being recycled for many times.

Example 2

The preparation method of the supported phosphotungstic acid solid acid catalyst comprises the following steps:

(1) pretreating the carrier: ZrO 2 is mixed with₂Placing in a muffle furnace, roasting at 400 deg.C for 2 hr to removeImpurities in the powder are removed, and the purity of the carrier is improved;

(2) 5g of the calcined ZrO were taken₂Adding 0.750g of phosphotungstic acid into 1.5mL of deionized water, and stirring for 1h at normal temperature; loading of phosphotungstic acid to ZrO by stirring₂A surface;

(3) standing the material obtained in the step (2) at normal temperature for 8h to completely impregnate the active component, and then drying in an oven at 100 ℃ for 12h to completely remove water;

(4) roasting the dried solid substance in air at 300 ℃ for 3h to obtain a catalyst with 15 wt% of phosphotungstic acid theoretical loading, which is recorded as (15) HPW/ZrO₂。

The (15) HPW/ZrO prepared in example 2₂Application of the catalyst in preparation of tert-butyl glyceryl ether by catalysis of glycerol:

4.144g of glycerol, 33.354g of tert-butanol and 0.414g of (15) HPW/ZrO₂Adding the catalyst into a 100mL stainless steel high-pressure reaction kettle, and adding N₂Repeatedly purging the reaction kettle for 3 times to remove air, reacting for 8h at 120 ℃, taking a small amount of reaction solution after the reaction is finished, and measuring the conversion rate of the glycerol to be 88.30 percent and the selectivity of the polysubstituted tert-butyl glycerol ether to be 48.39 percent.

Reacting (15) HPW/ZrO₂The catalyst is recovered after centrifugation, washing, drying and roasting, is continuously used as the catalyst to be applied to the reaction for preparing the tert-butyl glyceryl ether by the catalysis of the glycerol, and a small amount of reaction solution is taken after repeated recovery and repeated application for 4 times, and the conversion rate of the glycerol is determined to be 77.55%. The modified supported catalyst still has good catalytic effect after being recycled for many times.

Example 3

The preparation method of the supported phosphotungstic acid solid acid catalyst comprises the following steps:

(1) 5g of SnO were sampled₂Adding 0.5g of phosphotungstic acid into 5mL of deionized water, and stirring for 12h at normal temperature; loading phosphotungstic acid to SnO by stirring₂A surface;

(2) standing the material obtained in the step (1) at normal temperature for 10h to completely impregnate the active component, and then drying the material in a drying oven at the temperature of 110 ℃ for 12h to completely remove the water;

(3) roasting the dried solid substance in air at 400 ℃ for 3h to obtain a catalyst with 10 wt% of phosphotungstic acid theoretical loading, which is recorded as (10) HPW/SnO₂。

The (10) HPW/SnO prepared in example 3₂Application of the catalyst in preparation of tert-butyl glyceryl ether by catalysis of glycerol:

6.216g of glycerol, 30.019g of tert-butanol and 0.932g of (10) HPW/SnO₂Adding the catalyst into a 100mL stainless steel high-pressure reaction kettle, and adding N₂Repeatedly purging the reaction kettle for 3 times to remove air, reacting for 8h at 110 ℃, taking a small amount of reaction solution after the reaction is finished, and measuring the conversion rate of the glycerol to be 75.24 percent and the selectivity of the polysubstituted tert-butyl glyceryl ether to be 36.11 percent.

Reacting (10) HPW/SnO₂The catalyst is recovered after centrifugation, washing, drying and roasting, is continuously used as the catalyst to be applied to the reaction for preparing the tert-butyl glyceryl ether by catalyzing the glycerol, and a small amount of reaction solution is taken after repeated recovery and repeated application for 4 times, and the conversion rate of the glycerol is determined to be 68.52%. The modified supported catalyst still has good catalytic effect after being recycled for many times.

Example 4

The preparation method of the supported phosphotungstic acid solid acid catalyst comprises the following steps:

(1) 5g of SnO were sampled₂Adding 1g of phosphotungstic acid into 5mL of deionized water, and stirring for 12h at normal temperature; loading phosphotungstic acid to SnO by stirring₂A surface;

(2) standing the material obtained in the step (1) at normal temperature for 12h to completely impregnate the active component, and then drying the material in a drying oven at 100 ℃ for 10h to completely remove the water;

(3) roasting the dried solid substance in air at 300 ℃ for 4h to obtain a catalyst with the theoretical loading of phosphotungstic acid of 20 wt%, which is recorded as (20) HPW/SnO₂。

The (20) HPW/SnO prepared in example 4₂Application of the catalyst in preparation of tert-butyl glyceryl ether by catalysis of glycerol:

5g of glycerol, 32.195g of tert-butanol and 0.75g of (20) HPW/SnO₂Adding the catalyst into a 100mL stainless steel high-pressure reaction kettle, and adding N₂Repeatedly purging the reaction kettle for 3 times to remove air, reacting at 100 ℃ for 9 hours, taking a small amount of reaction solution after the reaction is finished, and determining that the conversion rate of the glycerol is 82.32% and the selectivity of the polysubstituted tert-butyl glyceryl ether is 38.51%.

Reacting (20) HPW/SnO₂The catalyst is recovered after centrifugation, washing, drying and roasting, is continuously used as the catalyst to be applied to the reaction for preparing the tert-butyl glyceryl ether by catalyzing the glycerol, and a small amount of reaction solution is taken after repeated recovery and repeated application for 4 times, and the conversion rate of the glycerol is determined to be 75.30%. The modified supported catalyst still has good catalytic effect after being recycled for many times.

Example 5

The preparation method of the supported phosphotungstic acid solid acid catalyst comprises the following steps:

(1) taking 5g of SiO₂Adding 0.75g of phosphotungstic acid into 10mL of deionized water, and stirring for 12h at normal temperature; loading phosphotungstic acid to SiO by stirring₂A surface;

(2) standing the material obtained in the step (1) at room temperature for 10h to completely soak the active components, and then drying the material in a drying oven at the temperature of 110 ℃ for 12h to completely remove the water;

(3) roasting the dried solid substance in air at 400 ℃ for 4h to obtain a catalyst with 15 wt% of phosphotungstic acid theoretical loading, which is recorded as (15) HPW/SiO₂。

The (15) HPW/SiO prepared in example 5₂Application of the catalyst in preparation of tert-butyl glyceryl ether by catalysis of glycerol:

4.144g of glycerol, 33.354g of tert-butanol and 0.414g of (15) HPW/SiO₂Adding the catalyst into a 100mL stainless steel high-pressure reaction kettle, and adding N₂Repeatedly purging the reaction kettle for 3 times to remove air, reacting for 8h at 110 ℃, taking a small amount of reaction solution after the reaction is finished, and measuring the conversion rate of the glycerol to be 90.80 percent and the selectivity of the polysubstituted tert-butyl glycerol ether to be 56.00 percent.

Reacting (15) HPW/SiO₂The catalyst is recovered after centrifugation, washing, drying and roasting, and then the catalyst is recoveredThe catalyst is continuously used in the reaction for preparing the tert-butyl glyceryl ether by catalyzing the glycerol, a small amount of reaction solution is taken after repeated recovery and repeated application for 4 times, and the conversion rate of the glycerol is determined to be 83.25%. The modified supported catalyst still has good catalytic effect after being recycled for many times.

Example 6

The preparation method of the supported phosphotungstic acid solid acid catalyst comprises the following steps:

(1) taking 5g of SiO₂Adding 1.25g of phosphotungstic acid into 10mL of deionized water, stirring at normal temperature for 12h, and loading the phosphotungstic acid to SiO by stirring₂A surface;

(2) standing the material obtained in the step (1) at room temperature for 12h to remove part of water, and then drying in an oven at 110 ℃ for 10h to completely remove the water;

(3) roasting the dried solid substance in air at 350 ℃ for 3h to obtain a catalyst with 25 wt% of phosphotungstic acid theoretical loading, which is recorded as (25) HPW/SiO₂。

The (25) HPW/SiO prepared in example 6₂Application of the catalyst in preparation of tert-butyl glyceryl ether by catalysis of glycerol:

3.5g of glycerol, 33.804g of tert-butanol and 0.525g of (25) HPW/SiO₂Adding the catalyst into a 100mL stainless steel high-pressure reaction kettle, and adding N₂Repeatedly purging the reaction kettle for 3 times to remove air, reacting for 11h at 100 ℃, taking a small amount of reaction solution after the reaction is finished, and measuring the conversion rate of the glycerol to be 71.69% and the selectivity of the polysubstituted tert-butyl glyceryl ether to be 35.87%.

Reacting (25) HPW/SiO₂The catalyst is recovered after centrifugation, washing, drying and roasting, is continuously used as the catalyst to be applied to the reaction for preparing the tert-butyl glyceryl ether by the catalysis of the glycerol, and a small amount of reaction solution is taken after repeated recovery and repeated application for 4 times, and the conversion rate of the glycerol is measured to be 60.34%. The modified supported catalyst still has good catalytic effect after being recycled for many times.

From examples 1 to 6, it is understood that the conversion rate of glycerol increases and then decreases, and the selectivity of polysubstituted tert-butyl glyceryl ether increases and then decreases with the increase of the loading amount of phosphotungstic acid on the carrier, and that the catalytic effect is best when the loading amount of phosphotungstic acid on the carrier is 15% of the mass of the carrier and the addition amount of the catalyst is 10% of the mass of glycerol, that is, the conversion rate of glycerol is the highest, and the selectivity of polysubstituted tert-butyl glyceryl ether is the highest. In addition, when the mass ratio of the catalyst to the reaction substrate glycerol is 1:10, the conversion rate of the obtained glycerol is the highest, and the selectivity of the polysubstituted tert-butyl glycerol ether is the highest.

Comparative examples

Non-modified SiO₂Application of the catalyst in preparation of tert-butyl glyceryl ether by catalysis of glycerol:

4.144g of glycerol, 33.354g of tert-butanol and 0.414g of SiO₂Adding the catalyst into a 100mL stainless steel high-pressure reaction kettle, and adding N₂Repeatedly purging the reaction kettle for 3 times to remove air, reacting for 8h at 110 ℃, taking a small amount of reaction solution after the reaction is finished, and measuring the conversion rate of the glycerol to be 16.55 percent and the selectivity of the polysubstituted tert-butyl glycerol ether to be 1.04 percent.

Reacting the SiO₂The catalyst is recovered after centrifugation, washing, drying and roasting, is continuously used as the catalyst to be applied to the reaction for preparing the tert-butyl glyceryl ether by catalyzing the glycerol, a small amount of reaction solution is taken after repeated recovery and repeated application for 2 times, the conversion rate of the glycerol is measured to be 13.93%, and a small amount of reaction solution is taken after repeated recovery and repeated application for 4 times, and the conversion rate of the glycerol is measured to be 10.06%.

From the above results, the glycerol conversion ratios of examples 1, 2, 3, 4, 5, and 6, which demonstrate the effectiveness of the present invention, are: 74.05%, 88.30%, 75.24%, 82.32%, 90.80%, 71.69%, and the selectivity of the multi-substituted tert-butyl glyceryl ether is 42.32%, 48.39%, 36.11%, 38.51%, 56.00%, 35.87%; the conversion of glycerol in the comparative example was 16.55%, and the selectivity to polysubstituted tert-butyl glycerol ether was 1.04%. It is easy to see that the synthetic process route of the invention greatly improves the conversion rate of the glycerol and the selectivity of the polysubstituted tert-butyl glycerol ether.