A catalyst special for synthesis of sec-butyl acetate, a preparation method and application thereof

Abstract

This invention belongs to the field of catalyst technology, and provides a dedicated catalyst for the synthesis of sec-butyl acetate, its preparation method, and its application. The invention first mixes water and a dispersant to obtain an aqueous phase. A functional monomer, a porogen, and an initiator are then added sequentially to the aqueous phase to carry out a polymerization reaction, yielding a prepolymer. The prepolymer is then mixed with a sulfonating agent and subjected to a sulfonation reaction to obtain a sulfonated resin. Finally, the sulfonated resin is mixed with a solvent and subjected to heat treatment to obtain the catalyst. The functional monomer includes a first monomer, a second monomer, and a crosslinking monomer. The second monomer includes at least one selected from butyl acrylate, butyl methacrylate, ethyl acrylate, and 2-ethylhexyl acrylate. This invention significantly reduces the catalyst's adsorption and reactivity to polycarbonate hydrocarbons, extends the catalyst's lifespan, and improves the selectivity of the catalyst for the synthesis of sec-butyl acetate.

Description

Technical Field

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

[0002] sec-butyl acetate (SBAC) has a wide range of applications and is consumed in large quantities due to its low toxicity and good performance. For example, SBAC can be used as a high-octane gasoline additive; industrially, it is used as a solvent in the manufacture of nitrocellulose lacquer, acrylic lacquer, and polyurethane lacquer; SBAC is also used in the manufacture of celluloid products, coated paper, and paint; it is used as a volatile solvent in printing inks; and it is used as a fast-drying agent in photosensitive materials. Industry insiders estimate that the demand for SBAC in coatings is approximately 3,000 tons per year, its application in printing inks is approximately 2,000-4,000 tons per year, and its use as a solvent to replace methyl isobutyl ketone (MIBK) is approximately 5,000 tons per year.

[0003] Generally, sec-butyl acetate is synthesized through two methods: esterification (alcoholization) and olefin addition (acid-olefin addition). Generally speaking, the esterification method uses sec-butanol, a raw material, which is currently expensive, resulting in low industrial value. The olefin addition method utilizes the reaction of butene and acetic acid in the presence of an ion-exchange resin catalyst to produce sec-butyl acetate. Compared with other liquid or solid acids, ion-exchange resin catalysts have superior catalytic performance, are easily separated from the product, are reusable, do not corrode equipment, and do not cause pollution, thus offering significant advantages. However, ion-exchange resin catalysts still have some problems that need improvement, such as insufficient specificity for various reactions, insufficient selectivity for the main reaction in the synthesis of sec-butyl acetate, and the tendency of superimposed side reactions to clog catalyst pores, leading to a shortened catalyst lifespan.

[0004] Therefore, there is an urgent need to develop a dedicated catalyst for the synthesis of sec-butyl acetate based on the acid-olefin addition method, which not only has strong reaction selectivity but also prevents byproducts from clogging the catalyst pores, thus effectively extending the catalyst's service life. Summary of the Invention

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a dedicated catalyst for the synthesis of sec-butyl acetate, its preparation method, and its application. The catalyst provided by this invention effectively improves the conversion rate and selectivity of the sec-butyl acetate reaction, achieving a butene conversion rate of up to 92% and a sec-butyl acetate selectivity of up to 99.4%. Simultaneously, by controlling the catalyst pore structure, by-reaction products are less likely to clog the catalyst pores, thus extending the catalyst's lifespan (230-248 days when activity begins to decline).

[0006] The first aspect of the present invention provides a method for preparing a catalyst specifically for the synthesis of sec-butyl acetate.

[0007] Specifically, a method for preparing a catalyst specifically for the synthesis of sec-butyl acetate includes the following steps: (1) Mix water and dispersant to obtain an aqueous phase; (2) The functional monomer, porogen and initiator are mixed and added to the aqueous phase to carry out a polymerization reaction to obtain a prepolymer; The oil phase includes functional monomers, initiators, and porogens, wherein the porogen accounts for 20-30% of the total mass of the oil phase. (3) The prepolymer and sulfonating agent are mixed and subjected to sulfonation reaction to obtain sulfonated resin; (4) The sulfonated resin is mixed with a solvent and subjected to heat treatment to obtain the catalyst; In step (2), the functional monomer includes a first monomer, a second monomer, and a crosslinking monomer; The second monomer includes at least one of butyl acrylate, butyl methacrylate, ethyl acrylate, and 2-ethylhexyl acrylate.

[0008] This invention introduces a polar second monomer containing double-bonded conjugations into the resin polymer chain, which increases the catalyst's adsorption of reactants and its compatibility with butene, acetic acid, and the product sec-butyl acetate. It significantly reduces the catalyst's adsorption and reactivity with polyalkylene hydrocarbons (byproducts), thereby greatly improving the selectivity of the catalyst for the synthesis of sec-butyl acetate and extending its lifespan. Furthermore, by controlling the proportion of pore-forming agent added, the catalyst's pore structure is controlled while simultaneously increasing its specific surface area.

[0009] Preferably, in step (1), the dispersant includes at least one of sodium dodecylbenzenesulfonate, disodium lauryl sulfonate monosuccinate, potassium monododecyl phosphate, and gelatin.

[0010] More preferably, in step (1), the dispersant is disodium lauryl sulfosuccinate monoester.

[0011] Preferably, in step (1), the mass of the dispersant accounts for 10-20% of the total mass of the aqueous phase.

[0012] More preferably, in step (1), the mass of the dispersant accounts for 15-20% of the total mass of the aqueous phase.

[0013] Preferably, in step (2), the mass ratio of the first monomer, the second monomer, and the crosslinking monomer is 60-90:10-40:3-10.

[0014] More preferably, in step (2), the mass ratio of the first monomer, the second monomer, and the crosslinking monomer is 71-80:23-30:6-10.

[0015] Preferably, in step (2), the first monomer includes styrene.

[0016] Preferably, in step (2), the second monomer is butyl acrylate and / or butyl methacrylate.

[0017] Preferably, in step (2), the crosslinking monomer includes at least one of divinylbenzene, divinyltoluene, divinylnaphthalene, ethylene glycol dimethacrylate, and diethylene glycol dimethacrylate.

[0018] More preferably, in step (2), the crosslinking monomer is divinylbenzene.

[0019] Preferably, in step (2), the first monomer, the second monomer, the crosslinking monomer and the initiator are mixed evenly and then added to the aqueous phase.

[0020] Preferably, in step (2), the initiator includes at least one of benzoyl peroxide, azobisisobutyronitrile, diisobutyronitrile peroxide, and tert-butyl peroxide.

[0021] Preferably, in step (2), the initiator accounts for 0.3-0.8% of the total mass of the oil phase.

[0022] Preferably, in step (2), the mass of the pore-forming agent accounts for 20-30% of the total mass of the oil phase.

[0023] More preferably, in step (2), the mass of the pore-forming agent accounts for 22-30% of the total mass of the oil phase.

[0024] Preferably, in step (2), the polymerization reaction includes the following steps: first, heating to 60-80℃ and reacting for 2-4 hours, then heating to 75-95℃ and reacting for 3-5 hours, and finally heating to 85-105℃ and reacting for 1-3 hours.

[0025] More preferably, in step (2), the polymerization reaction includes the following steps: first, heating to 70-80℃ and reacting for 3-4 hours, then heating to 85-95℃ and reacting for 4-5 hours, and finally heating to 95-105℃ and reacting for 2-3 hours.

[0026] Preferably, in step (2), after the polymerization reaction is completed, the pore-forming agent is extracted and dried.

[0027] Preferably, in step (2), the pore-forming agent includes at least one of isooctane, sec-butyl acetate, n-butyl acetate, and tert-butyl acetate.

[0028] More preferably, in step (2), the pore-forming agent is isooctane and sec-butyl acetate.

[0029] More preferably, in step (2), the pore-forming agent is isooctane and sec-butyl acetate in a mass ratio of (1-3):1.

[0030] More preferably, in step (2), the pore-forming agent is isooctane and sec-butyl acetate in a mass ratio of 1.5-2.5:1.

[0031] Preferably, in step (3), the sulfonating agent is added dropwise until it covers the catalyst.

[0032] Preferably, in step (3), the sulfonating agent includes at least one of fuming sulfuric acid, concentrated sulfuric acid, sulfur trioxide, and chlorosulfonic acid.

[0033] More preferably, in step (3), the sulfonating agent is fuming sulfuric acid.

[0034] More preferably, in step (3), the sulfonating agent is fuming sulfuric acid with a mass fraction of 15-30%.

[0035] Preferably, in step (3), the sulfonation reaction temperature is 70-120°C, and / or the sulfonation reaction time is 12-18h.

[0036] Preferably, in step (4), the solvent is water.

[0037] Preferably, in step (4), the heat treatment involves mixing the sulfonated resin with a solvent, soaking it at 90-110°C for 5-15 hours, and then separating the solid and liquid components to obtain the catalyst.

[0038] A second aspect of the present invention provides a catalyst specifically for the synthesis of sec-butyl acetate.

[0039] A catalyst specifically for the synthesis of sec-butyl acetate is prepared using the method described above.

[0040] A third aspect of the present invention provides an application of a catalyst specifically for the synthesis of sec-butyl acetate.

[0041] Application of a special catalyst for the synthesis of sec-butyl acetate in the preparation of sec-butyl acetate.

[0042] Preferably, the method for preparing sec-butyl acetate is an acid-olefin addition method.

[0043] Preferably, the raw materials for the preparation of the acid-olefin addition method include acetic acid and butene.

[0044] More preferably, the raw materials for the preparation of the acid-olefin addition method include acetic acid and butene in a molar ratio of 1-3:1.

[0045] More preferably, the raw materials for the preparation of the acid-olefin addition method include acetic acid and butene in a molar ratio of 2:1.

[0046] Preferably, the reaction temperature of the acid-alkene addition method is 80-90℃.

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention first mixes water and a dispersant to obtain an aqueous phase. A functional monomer, a porogen, and an initiator are then added sequentially to the aqueous phase to conduct a polymerization reaction, yielding a prepolymer. The prepolymer is then mixed with a sulfonating agent and subjected to a sulfonation reaction to obtain a sulfonated resin. Finally, the sulfonated resin is mixed with a solvent and subjected to heat treatment to obtain a catalyst. The functional monomer includes a first monomer, a second monomer, and a crosslinking monomer. The second monomer includes at least one of butyl acrylate, butyl methacrylate, ethyl acrylate, and 2-ethylhexyl acrylate. This invention introduces a polar second monomer into the resin polymer chain. Its double-bonded conjugation helps increase the catalyst's adsorption of reactants and its compatibility with butene, acetic acid, and the product sec-butyl acetate. It significantly reduces the catalyst's adsorption and reactivity to polyalkylene hydrocarbons (byproducts), thereby greatly improving the selectivity of the catalyst for the synthesis of sec-butyl acetate and extending the catalyst's lifespan. Furthermore, by controlling the proportion of the porogen added, the catalyst's pore structure is controlled while simultaneously increasing the catalyst's specific surface area. Using the catalyst of this invention, the butene conversion rate can reach 86-92%, the selectivity of sec-butyl acetate can reach 98.1-99.4%, and the running time can reach 230-248 days when the activity begins to decline. Detailed Implementation

[0048] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0049] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0050] Example 1 A method for preparing a catalyst specifically for the synthesis of sec-butyl acetate includes the following steps: (1) Add 10L of water to a 30L reactor, start stirring, add 15 parts of disodium lauryl sulfosuccinate monoester (dispersant, the amount of dispersant added is 15% of the aqueous phase) to obtain the aqueous phase.

[0051] (2) Take styrene (first monomer), butyl acrylate (second monomer), and divinylbenzene (crosslinking agent) in a mass ratio of 74:20:6, add a porogen (14.6 parts isooctane and 7.4 parts sec-butyl acetate, the porogen mass accounts for 22% of the total mass of the oil phase), and 0.5 parts benzoyl peroxide (initiator, the initiator mass accounts for 0.5% of the total mass of the oil phase, wherein the oil phase is composed of functional monomers, initiators and porogens), mix evenly, and then add to the aqueous phase, wherein the mass of the oil phase is 1 / 4 of the aqueous phase, and carry out the following polymerization reaction: first heat to 70℃, react for 3h, then heat to 85℃, react for 4h, and finally heat to 95℃, react for 2h. After the reaction is completed, filter and dry, extract the porogen with dichloroethane, and dry.

[0052] (3) Add 20% fuming sulfuric acid to the above product until it covers the surface of the white particles, and carry out sulfonation reaction. Control the reaction to gradually increase the temperature, keep it at 70°C for 2 hours, then increase the temperature to 90°C and keep it at 6 hours, then increase the temperature to 110°C and keep it at 4 hours. Finally, wash the product with water until it is neutral and set aside for later use.

[0053] (4) The above product was soaked in hot water at 100°C for 10 hours, and then the catalyst was separated. The above catalyst product was numbered YXC-1.

[0054] Example 2 A method for preparing a dedicated catalyst for the synthesis of sec-butyl acetate differs from Example 1 in that the mass ratio of styrene monomer to butyl acrylate is adjusted from 74:20 to 60:34. The catalyst product is designated YXC-2.

[0055] Example 3 A method for preparing a dedicated catalyst for the synthesis of sec-butyl acetate differs from Example 1 in that the mass ratio of styrene monomer to butyl acrylate is adjusted from 74:20 to 80:14. The catalyst product is designated YXC-3.

[0056] Comparative Example 1 A method for preparing a catalyst specifically for the synthesis of sec-butyl acetate differs from Example 1 in that the second monomer, butyl acrylate, is replaced with an equal mass of styrene.

[0057] Comparative Example 2 A method for preparing a catalyst specifically for the synthesis of sec-butyl acetate differs from Example 1 in that the porogen (a mixture of isooctane and sec-butyl acetate) is replaced with an equal mass of sec-butanol.

[0058] Comparative Example 3 A method for preparing a catalyst specifically for the synthesis of sec-butyl acetate differs from Example 1 in that the mass of the pore-forming agent accounts for 15% of the total mass of the oil phase.

[0059] Comparative Example 4 A method for preparing a catalyst specifically for the synthesis of sec-butyl acetate differs from Example 1 in that the mass of the pore-forming agent accounts for 35% of the total mass of the oil phase.

[0060] Product effectiveness test 1. Physicochemical properties of catalysts The physicochemical properties of the catalysts prepared in the above examples and comparative examples were tested respectively. The ion exchange capacity of the catalysts was determined by titration, the specific surface area and pore size of the catalysts were determined by the BET method, and the average particle size of the catalysts was determined by a laser particle size analyzer.

[0061] The test results are as follows: Table 1. Physicochemical property test results of catalysts in each example and comparative example.

[0062] As shown in the table above, the catalysts prepared in Examples 1-3 of this invention have an ion exchange capacity of 4.7-5.2 mmol / g and a specific surface area of ​​42-45 m². 2 / g, with a pore size of 35-38nm and an average particle size of 0.52-1.25mm.

[0063] 2. Catalytic performance of the catalyst Take 200 mL of fresh resin catalyst from each of the above examples and comparative examples, and place them in a fixed-bed reactor with an inner diameter of 25 mm and a length of 440 mm. Acetic acid and butene are precisely pumped in as raw materials to synthesize sec-butyl acetate, wherein the acid-to-butene molar ratio is 2.0, the reaction temperature is 85 °C, and the space velocity is 2 h⁻¹. -1 The pressure was 2 MPa. Data on the synthesis of sec-butyl acetate under different catalysts were measured to evaluate the activity and selectivity of each catalyst. The conversion and selectivity of sec-butyl acetate were determined using gas chromatography with internal standard method. The duration at which catalyst activity begins to decline refers to a 5% decrease in catalyst activity with no signs of recovery and a continued decline beginning.

[0064] The test results are as follows: Table 2. Effects of the catalysts used in each example and comparative example.

[0065] As shown in the table above, the catalysts prepared in Examples 1-3 of this invention achieve a butene conversion rate of 86-92% and a selectivity of sec-butyl acetate of 98.1-99.4%. The running time when the activity begins to decline is 230-248 days. This indicates that the resin catalyst prepared by this invention has high catalytic activity, high butene conversion rate and selectivity at medium and low temperatures (85℃), and long running time and lifespan, making it an excellent catalyst for the synthesis reaction of sec-butyl acetate.

[0066] The catalyst in Comparative Example 1 showed low selectivity for sec-butyl acetate, and byproducts easily clogged the catalyst pores, leading to catalyst deactivation and hindering efficient synthesis of sec-butyl acetate. The catalyst in Comparative Example 2 exhibited low butene conversion. The catalysts in Comparative Examples 3 and 4 not only showed low butene conversion but also low selectivity for sec-butyl acetate.

Claims

1. A method for preparing a catalyst, characterized in that, Includes the following steps: (1) Mix water and dispersant to obtain an aqueous phase; (2) The functional monomer, porogen and initiator are mixed and added to the aqueous phase to carry out a polymerization reaction to obtain a prepolymer; The oil phase includes functional monomers, initiators, and porogens, wherein the porogen accounts for 20-30% of the total mass of the oil phase. (3) The prepolymer and sulfonating agent are mixed and subjected to sulfonation reaction to obtain sulfonated resin; (4) The sulfonated resin is mixed with a solvent and subjected to heat treatment to obtain the catalyst; In step (2), the functional monomer includes a first monomer, a second monomer, and a crosslinking monomer; The second monomer includes at least one of butyl acrylate, butyl methacrylate, ethyl acrylate, and 2-ethylhexyl acrylate.

2. The preparation method according to claim 1, characterized in that, In step (2), the polymerization reaction includes the following steps: first, heating to 60-80℃ and reacting for 2-4 hours, then heating to 75-95℃ and reacting for 3-5 hours, and finally heating to 85-105℃ and reacting for 1-3 hours.

3. The preparation method according to claim 1, characterized in that, The mass ratio of the first monomer, the second monomer, and the crosslinking monomer is 60-90:10-40:3-10.

4. The preparation method according to claim 1, characterized in that, The first monomer includes styrene.

5. The preparation method according to claim 1, characterized in that, In step (2), the crosslinking monomer includes at least one of divinylbenzene, divinyltoluene, divinylnaphthalene, ethylene glycol dimethacrylate, and diethylene glycol dimethacrylate.

6. The preparation method according to claim 1, characterized in that, In step (2), the initiator accounts for 0.3-0.8% of the total mass of the oil phase.

7. The preparation method according to claim 1, characterized in that, In step (2), the pore-forming agent includes at least one of isooctane, sec-butyl acetate, n-butyl acetate, and tert-butyl acetate.

8. The preparation method according to claim 1, characterized in that, In step (4), the heat treatment involves mixing the sulfonated resin with a solvent, soaking it at 90-110°C for 5-15 hours, and then separating the solid and liquid components.

9. A catalyst, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. The use of the catalyst according to claim 9 in the preparation of sec-butyl acetate.

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