CN108940278B - Method for preparing prenol through prenyl acetate transesterification reaction - Google Patents

Abstract

The invention relates to a method for preparing prenol through prenyl acetate transesterification. The method is characterized in that a transesterification reaction is catalyzed by adopting a solid acid catalyst. The solid acid catalyst is one or more than two of the following: the supported noble metal catalyst comprises a composite oxide formed by one or two of silicon dioxide or aluminum trioxide and cerium dioxide, and a supported noble metal catalyst taking one or more of the composite oxide or the cerium dioxide as a carrier, wherein the noble metal component is one or more of iridium, gold and rhodium, and the supported noble metal catalyst contains or does not contain an auxiliary agent which is one or two of iron or cobalt. The synthesis method adopted by the invention can ensure that the isoamylene acetate and the methanol are converted and esterified into the isopentenol with high conversion rate and high selectivity under certain pressure and temperature under the catalysis of the prepared solid acid catalyst.

Description

Method for preparing prenol through prenyl acetate transesterification reaction

Technical Field

The invention relates to a method for preparing prenol through prenyl acetate transesterification.

Background

The isopentenol is a colorless oily liquid and is an important intermediate of medicines, pesticides and spices, and the chemical name of the isopentenol is 3-methyl-3-buten-1-ol. In the traditional industrial field, the method is mainly used for producing isophytol, DV pyrethrin, citral and downstream products thereof, and the like, and in recent years, the novel application is used for synthesizing TPEG and the like which are raw materials of third-generation cement water reducing agents and polycarboxylic acid water reducing agents.

The synthetic route for preparing the isopentenol by the acetic acid foreign body alkene ester transesterification reaction has the advantages of simple process conditions, mild reaction conditions, few byproducts, lower production cost and environmental friendliness, is an efficient and economic synthetic method, and has the specific reaction formula shown in the following formula:

the solid acid catalyst is the most industrially used acid catalyst, and is widely used for catalytic cracking of hydrocarbons, catalytic structuring of olefins, alkylation of aromatic hydrocarbons and olefins, polymerization of olefins with each other, transesterification of ester alcohols, and the like. As an environment-friendly catalyst, the preparation method of the solid acid catalyst is generally simple, an impregnation method and a precipitation method are generally adopted, and the solid acid catalysts with different acid strengths can be prepared according to different raw materials and different mutual mixing amounts, so that the requirements of different reactions are met. So far, few documents report that a solid acid catalyst is used for catalyzing the reaction of converting acetic acid isoamylene ester into isopentenol. Therefore, the solid acid catalyst for preparing the isopentenol by the prenyl acetate transesterification reaction has certain practical significance for future industrial application.

Disclosure of Invention

The invention aims to provide a method for preparing prenol through prenyl acetate transesterification. The method is characterized in that a transesterification reaction is catalyzed by adopting a solid acid catalyst. The solid acid catalyst is one or more than two of the following: the supported noble metal catalyst comprises a composite oxide formed by one or two of silicon dioxide or aluminum trioxide and cerium dioxide, and a supported noble metal catalyst taking one or more of the composite oxide or the cerium dioxide as a carrier, wherein the noble metal component is one or more of iridium, gold and rhodium, and the supported noble metal catalyst contains or does not contain an auxiliary agent which is one or two of iron or cobalt. The catalyst prepared by the invention can ensure that the isoamylene acetate and methanol are converted and esterified into the isopentenol with high conversion rate and high selectivity under certain pressure and temperature.

The invention is realized by the following technical scheme:

the invention provides a method for preparing prenol through prenyl acetate transesterification. The method is characterized in that a transesterification reaction is catalyzed by adopting a solid acid catalyst. The solid acid catalyst is one or more than two of the following:

a composite oxide of cerium oxide and one or both of silicon dioxide and aluminum trioxide,

one or more of the composite oxide or the cerium dioxide is/are used as a carrier of the supported noble metal catalyst, and the noble metal component is one or more of iridium, gold and rhodium;

the supported noble metal catalyst contains or does not contain an auxiliary agent, and the auxiliary agent is one or two oxides of iron or cobalt.

The mass content of the cerium dioxide in the composite oxide is 5-50%, preferably 10-30%;

the mass loading amount of the noble metal in the supported noble metal catalyst is 0.01-5%, preferably 0.01-2%;

the mass content of the auxiliary agent in the supported noble metal catalyst is 0-10%, usually 1-10%, preferably 2-8% calculated by metal simple substance.

The preparation of the composite oxide adopts an isometric impregnation method, and the specific process is as follows: one or two of silicon dioxide or aluminum trioxide is used as a carrier, and then a proportioned soluble cerium salt aqueous solution is subjected to incipient wetness impregnation on the carrier for 5-24 hours, dried in an oven at 60-100 ℃ for more than 10 hours, and calcined in a muffle furnace at 300-600 ℃ for 1-10 hours to obtain the composite oxide.

The preparation of the load type noble metal catalyst adopts an isometric impregnation method, and the specific process is as follows: the method comprises the steps of impregnating a soluble precious metal precursor aqueous solution onto a carrier in an incipient wetness manner, adding or not adding one or two of soluble metal salts of iron or cobalt into the soluble precious metal precursor aqueous solution, wherein the impregnation time is 5-24 hours, drying the soluble precious metal precursor aqueous solution in an oven at 60-100 ℃ for more than 10 hours, and calcining the soluble precious metal precursor aqueous solution in a muffle furnace at 300-400 ℃ for 2-5 hours to obtain the supported precious metal catalyst.

The finally prepared supported noble metal catalyst is prepared in H₂And (3) reducing at the temperature of 200-600 ℃ for 0.5-5 h.

The prenyl alcohol preparation reaction by the conversion esterification of the prenyl acetate is carried out in a batch high-pressure reaction kettle or a fixed bed reactor.

The reaction conditions of the catalyst in the batch high-pressure reaction kettle are as follows: the reaction raw material is a mixed solution of isoamylene acetate and methanol, wherein the mass concentration of the isoamylene acetate is 10-70%, the hydrogen pressure is 0.1-10 MPa, the reaction temperature is 100-200 ℃, the reaction time is 1-10 h, and the mass ratio of the catalyst amount to the reaction raw material is 1-10%.

The reaction conditions of the catalyst in the fixed bed reactor are as follows: the reaction raw material is a mixed solution of isoamylene acetate and normal alcohol of C1-C4, wherein the mass concentration of the isoamylene acetate is 10-80%, the hydrogen pressure is 1-5 MPa, the reaction temperature is 100-200 ℃, the reaction time is 10-200 h, and the catalyst dosage relative to the volume space velocity of the reaction liquid is 1-5 g.

According to said method, it is characterized in that: the normal alcohol of C1-C4 is one or more of methanol, ethanol, propanol and n-butanol, and the corresponding acetate is one or more of methyl acetate, ethyl acetate, propyl acetate and butyl acetate.

Detailed Description

Example 1 (comparative example)

The catalyst is CeO purchased from the national medicine group₂Selecting an intermittent reaction kettle, wherein the catalytic reaction conditions are as follows: 0.5g of isoamylene acetate was mixed with 1.0mL of methanol, 50mg of a catalyst was added thereto, and the reaction was carried out at a temperature of 140 ℃ to carry out the reactionThe pressure is 4Mpa, and the reaction time is 1.5 h;

example 2

Using a catalyst of CeO₂The preparation method comprises the following specific steps of (1) loading noble metal Ir (the mass fraction of Ir is 2%) on a carrier: the proportioned chloroiridic acid aqueous solution is subjected to primary wet impregnation on a carrier for 24 hours, dried in an oven at 80 ℃ for 12 hours and calcined in a muffle furnace at 350 ℃ for 2 hours to prepare 2 percent Ir/CeO₂A solid acid catalyst. The prepared catalyst is reduced for 2 hours at 350 ℃ in a hydrogen atmosphere. The reaction conditions are as follows: 0.5g of isoamylene acetate is mixed with 1.0mL of methanol, 50mg of catalyst is added, the reaction temperature is 140 ℃, the reaction pressure is 4Mpa, and the reaction time is 1.5 h.

Example 3 (comparative example)

The carrier CeO₂By conversion to TiO₂Other conditions were the same as in example 2.

Example 4 (comparative example)

The carrier CeO₂By conversion to ZrO₂Other conditions were the same as in example 2.

Example 5 (comparative example)

The carrier CeO₂By conversion to Al₂O₃Other conditions were the same as in example 2.

Example 6

The supported amount of the noble metal Ir was changed to 5%, and the other conditions were the same as in example 2.

Example 7 (comparative example)

The noble metal Ir was changed to Au, and the other conditions were the same as in example 3.

Example 8 (comparative example)

The noble metal Ir was changed to Ru and other conditions were the same as in example 3.

Example 9

The reaction time was extended to 2h, and the other conditions were the same as in example 2.

Example 10

Using a catalyst of CeO₂Noble metal Ir (the mass fraction of Ir is 2%) is loaded on the carrier, and iron is added as an auxiliary agent (the mass fraction is 5%). The preparation process comprises the following steps: proportionally mixing chloroiridic acid aqueous solution and ferric nitrate aqueous solutionMixing, soaking in 80 deg.C oven for 15h, drying for 15h, and calcining in muffle furnace at 350 deg.C for 2h to obtain 2% Ir-5% Fe/CeO₂A solid acid catalyst. The catalyst reduction conditions and reaction conditions were the same as in example 1.

Example 11

The additive Fe was changed to Co, cobalt nitrate was used as a precursor, and the other conditions were the same as in example 10.

Example 12

Soaking the proportioned chloroiridic acid aqueous solution (calculated according to the mass fraction of Ir of 2%) to Al in an incipient wetness manner₂O₃Soaking on a powder carrier for 10h, drying in an oven at 80 ℃ for 16h, and calcining in a muffle furnace at 350 ℃ for 3 h to obtain Ir/Al₂O₃. Mixing the prepared cerous nitrate aqueous solution (according to the formula of CeO)₂Calculated as 30% mass fraction) to Ir/Al₂O₃Soaking for 6h, drying in an oven at 80 deg.C for 15h, and calcining in a muffle furnace at 450 deg.C for 2h to obtain 2% Ir-30% CeO₂/Al₂O₃A solid acid catalyst. A batch type high-pressure reaction kettle is selected, and the reduction conditions and the reaction conditions of the catalyst are the same as those of the example 2.

Example 13

Forming the SiO with 40-60 meshes₂As a carrier, CeO is supported on the carrier₂(the mass fraction is 10%) and the preparation process comprises the following steps: preliminarily soaking the proportioned cerous nitrate aqueous solution on a carrier for 6 hours, drying in a drying oven at 80 ℃ for 12 hours, and calcining in a muffle furnace at 450 ℃ for 2 hours to obtain 10 percent CeO₂/SiO₂A solid acid catalyst. Selecting a fixed bed reactor, wherein the reaction conditions are as follows: 10% isoamylene acetate solution (methanol as solvent), the raw material sample amount is 2mL/min, 2g catalyst is added, the reaction temperature is 130 ℃, the reaction pressure is 2Mpa, and the reaction time is 30 h.

Example 14

Mixing the prepared cerous nitrate aqueous solution (according to the formula of CeO)₂Calculated by 10 percent of mass fraction) and ferric nitrate aqueous solution (calculated by 5 percent of mass fraction of Fe element) are mixed evenly, and the impregnation liquid is impregnated to SiO 40-60 meshes above the solution in an incipient wetness manner₂In the immersion time ofDrying in an oven at 80 deg.C for 12h for 8h, and calcining at 450 deg.C in a muffle furnace for 2h to obtain 5% Fe-10% CeO₂/SiO₂A solid acid catalyst. Selecting a fixed bed reactor, wherein the reaction conditions are as follows: 10% isoamylene acetate solution (methanol as solvent), the raw material sample amount is 2mL/min, 2g catalyst is added, the reaction temperature is 130 ℃, the reaction pressure is 2Mpa, and the reaction time is 30 h.

Example 15

Soaking the proportioned chloroiridic acid aqueous solution (calculated according to the mass fraction of Ir of 1%) to the formed SiO with 40-60 meshes in an incipient wetness manner₂Soaking for 6h, drying in an oven at 80 ℃ for 12h, and calcining in a muffle furnace at 350 ℃ for 2h to obtain Ir/SiO₂. Mixing the prepared cerous nitrate aqueous solution (according to the formula of CeO)₂Calculated by mass fraction of 30%) is dipped into Ir/SiO₂Soaking for 5h, drying in an oven at 80 deg.C for 15h, calcining in a muffle furnace at 450 deg.C for 2h to obtain 1% Ir-30% CeO₂/SiO₂A solid acid catalyst. The prepared catalyst is reduced for 2 hours at 400 ℃ in a hydrogen atmosphere. The reaction conditions were the same as in example 13.

Example 16

The Ir loading was changed to 0.3% and the other conditions were the same as in example 15.

Example 17

Soaking the proportioned chloroiridic acid aqueous solution (calculated according to the mass fraction of Ir of 0.1%) to the formed SiO with 40-60 meshes in an incipient wetness manner₂Soaking for 6h, drying in an oven at 80 ℃ for 12h, and calcining in a muffle furnace at 350 ℃ for 2h to obtain Ir/SiO₂. Proportionally mixing ferric nitrate aqueous solution (calculated according to the mass fraction of Fe being 5%) and cerous nitrate aqueous solution (calculated according to CeO)₂Calculated by mass fraction of 30%) and dipping the dipping solution into Ir/SiO₂Soaking for 5h, drying in an oven at 80 deg.C for 15h, calcining in a muffle furnace at 450 deg.C for 2h to obtain 0.1% Ir-5% Fe/30% CeO₂/SiO₂A solid acid catalyst. The catalyst reduction conditions and reaction conditions were the same as in example 15.

Example 18

Adding CeO₂The mass fraction becomes 20%, whichThe conditions were the same as in example 15.

TABLE 1 comparison of catalytic Properties of prenyl acetate esterification to prenol

a. Others are

One or more of 1-pentene, pentadiene, 3-methyl-1-butene, acetic acid, etc.;

the above description is of the preferred embodiment of the present invention and is not intended to limit the invention in any way or manner. It should be understood that all changes, modifications and equivalents that can be made by one skilled in the art without departing from the spirit and scope of the invention as described above are equivalent embodiments of the invention; meanwhile, any changes, modifications and evolution of the equivalent changes of the above embodiments according to the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims (8)

1. A method for preparing prenol through prenyl acetate transesterification is characterized in that: the method adopts a noble metal catalyst to carry out catalytic transesterification reaction;

the noble metal catalyst is:

a composite oxide of ceria and one or both of silica and alumina, a supported noble metal catalyst in which one or both of the composite oxide and ceria is supported,

the noble metal component is one or more than two of iridium, gold and rhodium;

the supported noble metal catalyst contains or does not contain an auxiliary agent, and the auxiliary agent is one or two of iron or cobalt;

the mass content of cerium dioxide in the composite oxide is 5-50%;

the mass loading amount of the noble metal in the loaded noble metal catalyst is 0.01-5%;

the mass content of the auxiliary agent in the supported noble metal catalyst is 0-10% by metal simple substance.

2. The method of claim 1, wherein: the mass content of cerium dioxide in the composite oxide is 10-30%;

the mass loading of the noble metal in the loaded noble metal catalyst is 0.01-2%;

the mass content of the auxiliary agent in the supported noble metal catalyst is 2-8% by metal simple substance.

3. The method of claim 2, wherein:

the preparation of the composite oxide adopts an isometric impregnation method, and the specific process is as follows: one or two of silicon dioxide or aluminum trioxide is used as a carrier, and then a proportioned soluble cerium salt aqueous solution is subjected to incipient wetness impregnation on the carrier for 5-24 hours, dried in an oven at 60-100 ℃ for more than 10 hours, and calcined in a muffle furnace at 300-600 ℃ for 1-10 hours to obtain the composite oxide.

4. A method according to claim 3, characterized by:

the preparation of the load type noble metal catalyst adopts an isometric impregnation method, and the specific process is as follows: and (2) carrying out incipient wetness impregnation on the obtained composite oxide by using a soluble precious metal precursor aqueous solution, adding or not adding one or two of soluble metal salts of iron or cobalt into the soluble precious metal precursor aqueous solution, wherein the impregnation time is 5-24 h, drying in an oven at 60-100 ℃ for more than 10h, and calcining in a muffle furnace at 300-400 ℃ for 2-5 h to obtain the supported precious metal catalyst.

5. The method of claim 4, wherein: the finally prepared supported noble metal catalyst is prepared in H₂And (3) reducing at the temperature of 200-600 ℃ for 0.5-5 h.

6. The method according to any one of claims 1 to 5, wherein: the prenyl alcohol preparation reaction by the conversion esterification of the prenyl acetate is carried out in a batch high-pressure reaction kettle or a fixed bed reactor.

7. The method of claim 6, wherein:

the reaction conditions of the catalyst in the batch high-pressure reaction kettle are as follows: the reaction raw material is a mixed solution of isoamylene acetate and methanol, wherein the mass concentration of the isoamylene acetate is 10-70%, the hydrogen pressure is 0.1-10 MPa, the reaction temperature is 100-200 ℃, the reaction time is 1-10 h, and the mass ratio of the catalyst to the reaction raw material is 1-10%.

8. The method of claim 6, wherein:

the reaction conditions of the catalyst in the fixed bed reactor are as follows: the reaction raw material is a mixed solution of isoamylene acetate and normal alcohol of C1-C4, wherein the mass concentration of the isoamylene acetate is 10-80%, the hydrogen pressure is 1-5 MPa, the reaction temperature is 100-200 ℃, the reaction time is 10-200 h, and the catalyst dosage relative to the volume space velocity of the reaction liquid is 1-5 g.