CN111944083A

CN111944083A - Preparation method of modified macroporous acidic cation exchange resin

Info

Publication number: CN111944083A
Application number: CN201910395833.5A
Authority: CN
Inventors: 蔡依进; 王兴路; 卢方亮; 杨朔; 郑吉振; 孙华; 张月凤; 李文强
Original assignee: Shandong Chenxin New Energy Co ltd
Current assignee: Shandong Chenxin New Energy Co ltd
Priority date: 2019-05-14
Filing date: 2019-05-14
Publication date: 2020-11-17
Anticipated expiration: 2039-05-14
Also published as: CN111944083B

Abstract

The invention belongs to the technical field of energy chemical catalysis, and provides a preparation method of modified macroporous acidic cation exchange resin, which comprises the following steps: firstly, pre-polymerizing acrylic monomers into a macromolecular plasticizer in an aqueous solution, then adding inorganic whisker to polymerize styrene and divinylbenzene into macroporous white spheres, sulfonating the white spheres into acidic cation exchange resin, and then complexing the acidic cation exchange resin with amphoteric metal oxide to form the elastic cation exchange resin spheres with stable structures and macropores and regular channels.

Description

Preparation method of modified macroporous acidic cation exchange resin

Technical Field

The invention belongs to the technical field of energy chemical catalysis, and particularly discloses a preparation method of a modified macroporous acidic cation exchange resin.

Background

Polyoxymethylene dimethyl ether, english name: polyoxymethylene dimethyl ethers, PODE or DMMn for short, are low molecular weight acetal polymers with dimethoxymethane as the matrix and methyleneoxy as the main chain, and the general formula is shown as follows: CH3O (CH2O) nCH 3. The polyoxymethylene dimethyl ethers with the polymerization degree of 3-8, DMM3-8 for short, is used for cleaning diesel blending components, has physical properties similar to diesel, and is used for blending into the diesel without modifying an oil supply system of a vehicle engine. The cetane number of the diesel oil reaches 76, the oxygen content is 47-50%, the diesel oil is free of sulfur and aromatic hydrocarbon, the diesel oil can be blended in the diesel oil by 10-20%, the cold filter plugging point of the diesel oil can be obviously reduced, the combustion quality of the diesel oil in an engine can be improved, and the thermal efficiency is improved. Meanwhile, DMM3, DMM4 and DMM5 are solvents with extremely strong dissolving capacity, and are applied to paint, coating, printing ink, adhesives, cleaning agents, electrolyte solvents and the like.

The polymethoxy dimethyl ether is prepared by reacting methanol or methylal with formaldehyde solution, trioxymethylene or paraformaldehyde in the presence of an acid catalyst, only cation exchange resin is applied to synthesis and production of the polymethoxy dimethyl ether in a plurality of acid catalysts, and the polymethoxy dimethyl ether has the advantages of multiple aspects, has no corrosion to equipment (fixed bed catalysis and fluidized bed catalysis can be arranged), has no wastewater generation, is green and environment-friendly, can be applied to a plurality of forms (powder, ring, rod, spherical particle, fiber and the like), can be repeatedly applied and is easy to regenerate after being inactivated, and has great industrial application prospect; however, the existing cation exchange resin catalyst has partial defects: low catalytic ability, low utilization degree, low mechanical strength, low high temperature resistance, easy inactivation, difficult adjustment of acid strength and easy generation of more impurities.

In order to fully exert the catalytic function of the cation exchange resin on the industrial road of the polymethoxy dimethyl ether, the cation exchange resin catalyst needs to be optimized and improved.

Disclosure of Invention

(1) The purpose of the invention is as follows: the invention aims to provide a preparation method of modified macroporous cation exchange resin, which is applied to synthesis of polymethoxy dimethyl ether and has the advantages of strong malleability, high catalytic activity, stable high-temperature performance, less impurity generation, stable synthetic liquid, easy separation and the like. Solves the basic problems of the current polymethoxy dimethyl ether synthesis process and the later separation.

(2) The technical scheme is as follows: the preparation method of the modified macroporous acidic cation exchange resin comprises the following steps: firstly, pre-polymerizing acrylic monomers into a macromolecular plasticizer in an aqueous solution, then adding inorganic whisker to polymerize styrene and divinylbenzene into macroporous white spheres, sulfonating the white spheres into acidic cation exchange resin, and then complexing the acidic cation exchange resin with amphoteric metal oxide to form the elastic cation exchange resin spheres with stable structure and macropores and regular channels

(3) The technical effects are as follows: the preparation method of the modified macroporous acidic cation exchange resin has the advantages of easily available raw materials, high toughness, high catalytic activity, stable high-temperature performance, less impurity generation, stable and easily separated synthetic liquid and the like when the prepared modified macroporous acidic cation exchange resin is applied to synthesis of polymethoxy dimethyl ether. Solves the basic problems of the current polymethoxy dimethyl ether synthesis process and the later separation.

The concrete aspects are as follows:

1. the invention adopts plasticizer, inorganic whisker and amphoteric metal oxide salt pre-polymerized by acrylic monomers, and has the advantages of easily obtained raw materials, simple use and lower product modification cost.

2. The modified macroporous acidic cation exchange resin prepared by the invention has high toughness and is not easy to break.

3. The modified macroporous acidic cation exchange resin prepared by the invention is applied to synthesis of polymethoxy dimethyl ether, and has smooth molecular motion and large catalytic capacity.

4. The modified macroporous acidic cation exchange resin prepared by the invention has stable high-temperature performance, is applied to synthesis of polymethoxy dimethyl ether, generates less impurities, and is stable and easy to separate synthetic liquid.

The specific implementation mode of the invention is as follows:

example 1: the plasticizer is prepared by dissolving 300g of water, 0.5g of polyvinyl alcohol, 8g of methyl acrylate and 0.5g of benzoyl peroxide in a 500mL stainless steel polymerization kettle, stirring, heating to 80 ℃, and reacting at constant temperature for 5 hours.

Example 2: polymerization: then 6g of calcium carbonate whiskers are added, the temperature is raised to 60 ℃, an organic phase mixture consisting of 57g of styrene (the styrene content is more than or equal to 99%), 20g of divinylbenzene (the divinylbenzene content is 50%), 30g of No. 32 white oil and 0.5g of benzoyl peroxide is added, the mixture is stirred and heated to 86 ℃, and the constant temperature reaction is carried out for 10 hours. And filtering the reaction product, and airing at room temperature (the water content is less than or equal to 3%) to obtain 110g of dry polymer white balls, wherein the polymer with the particle size range of 0.3-6.0 mm accounts for 85.2%. Example 3: pore structure purification, namely putting 110g of dry white spheres into a Soxhlet extractor, hermetically connecting the extractor with a 500mL round-bottom flask filled with 250mL of toluene, heating the toluene in the flask, and extracting the white spheres for 2.5 hours. The white ball was transferred to another 500ml flask, 250ml of water was added, and the mixture was heated to 80 ℃ and stirred for 1 hour. Suck the bottle out, take the white ball out, place in 80C oven dry to moisture content <1% example 4: sulfonation, adding 50g of purified dry polymer white balls and 100g of 120% fuming sulfuric acid into a 500mL round-bottom flask, stirring and heating to 85 ℃, reacting at constant temperature for 6 hours, slowly heating to 120 ℃, reacting at constant temperature for 5 hours, and cooling. Then transferring the sulfonated materials into 500ml in batches, controlling the temperature below 40 ℃, and after the transfer is finished, extracting the water phase in the flask.

Example 5: coordination and addition: adding 200ml of ethanol into the treated acidic resin, adding 10g of anhydrous aluminum chloride, heating and refluxing for 10 hours, then dropwise adding deionized water into the kettle at the temperature of less than 40 ℃, and then pumping out the water phase until the liquid is neutral. Then the product in the kettle is centrifugally filtered and dried to obtain the modified hydrogen type macroporous cation exchange resin. The main physical properties are shown in Table 1.

Example 6 evaluation of stability of sulfonic acid group: 20g of the resin was taken out and boiled in 200ml of isopropyl alcohol at a stirring rate of 300 rpm for 500 hours under normal pressure at a temperature of 82.5 ℃ and taken out, and the sulfonic acid group-dropping rate and the mass of the floating powder in the isopropyl alcohol solution were measured, and the results are shown in Table 1. Example 7 evaluation of catalytic Activity for Synthesis of polyoxymethylene dimethyl ethers: 10ml of the dried resin catalyst is taken and put into a 1000mm pressure reactor for the synthetic reaction of the polymethoxy dimethyl ether. The results of activity, conversion, selectivity and separation of materials of the catalyst obtained under the reaction conditions of methylal/trioxane =2.1 (mass ratio), time 2 hours, reaction temperature 40 ℃, 60 ℃, 80 ℃, 100 ℃, 120 ℃, stirring rate 120 rpm and pressure 0-1.0MPa are shown in Table 2, the conversion rate graph is shown in FIG. 1, and the impurity formation rate graph is shown in FIG. 2.

10ml of the comparative catalyst is respectively taken and put into a 1000mm pressure reactor for the synthetic reaction of the polymethoxy dimethyl ether. The reaction conditions were methylal/trioxane =2.1 (mass ratio), time was 2 hours, reaction temperature was 40 ℃, 60 ℃, 80 ℃, 100 ℃, 120 ℃, stirring rate was 120 rpm, and the catalyst activity, conversion rate, selectivity, and material separation were performed under a pressure of 0.3MPa, and the results are shown in table 2. The conversion rate is shown in the graph of FIG. 1, and the impurity formation rate is shown in the graph of FIG. 2.

TABLE 1

Item	Example samples	Comparative sample
			Lot or model number	Modified ion exchange resin 1#	CT175 macroporous ion exchange resin
Appearance of the product	Yellowish brown spherulites	Dark gray spherulites
			Particle size/mm	0.3-0.8	0.3-1.2
Exchange Capacity/mmol. g-1	4.58	4.71
			Sulfonic acid group falling rate/mmol g-1 h-1	0.6X10^-4	4.4X10^-4
Mass/g of floating powder	No detection	0.015g (ratio 0.075%)

TABLE 2

Description of the drawings:

FIG. 1 is a graph of the conversion at different temperatures for the comparison of example sample No. 1 and comparative sample (CT 175), with the abscissa being the temperature from 40 ℃ to 120 ℃ and the ordinate being the conversion from 50% to 100%;

FIG. 2 is a graph showing the impurity formation rate at different temperatures in comparison of example sample No. 1 and comparative sample (CT 175), with the abscissa representing the temperature from 40 ℃ to 120 ℃ and the ordinate representing the impurity formation rate from 0.0% to 5.0%;

specifically, the following description is provided:

the invention solves the problems that when one or more of paraformaldehyde, trioxymethylene, formaldehyde aqueous solution, methanol, methylal, dimeric formaldehyde dimethyl ether and the like are taken as raw materials to produce polymethoxy dimethyl ether at present, the reaction activity of a molecular sieve catalyst is low, and the product is difficult to form; catalysts such as liquid acid and ionic liquid are not easy to separate, so that products are decomposed during subsequent separation, and equipment is seriously corroded; the existing macroporous ion exchange resin is used, catalyst particles are easy to break, acid groups are easy to fall off and inactivate, the catalytic efficiency is low, the impurity generation rate is high, and the like, so that the cost is high, and residual formaldehyde in the product is not easy to apply. The acidic macroporous cation exchange resin prepared by modification according to the design scheme has the advantages of easily obtained raw materials and simple preparation process, is used as a catalyst, is applied to the preparation of polymethoxy dimethyl ether, and preliminarily embodies the following compared with the existing macroporous cation exchange resin: strong toughness, high catalytic activity, stable high-temperature performance, less impurity generation, stable and easily separated synthetic liquid and the like. Solves the basic problems of the current polymethoxy dimethyl ether synthesis process and the later separation.

Finally, it is to be noted that: although the present invention has been described in detail with reference to the foregoing examples, it will be apparent to those skilled in the art that changes may be made in the embodiments and equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The preparation process of modified macroporous acid cation exchange resin includes the following steps: firstly, methyl acrylate monomers are prepolymerized into a macromolecular plasticizer in an aqueous solution, then styrene and divinylbenzene are polymerized into macroporous white spheres under the condition of adding inorganic whisker, then the white spheres are sulfonated into acidic cation exchange resin, and then the acidic cation exchange resin is complexed by using amphoteric metal oxide to form the elastic cation exchange resin spheres with stable structure and macropores and regular channels.

2. The plasticizer raw material as claimed in claim 1, wherein the acrylic monomer includes acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, etc.

3. The inorganic whiskers used for the regular channel former as claimed in claim 1 include calcium carbonate whiskers, calcium sulfate whiskers, zinc oxide whiskers, etc.

4. The salt of an amphoteric metal oxide for an acid site complexing agent as claimed in claim 1 comprising: zinc chloride, aluminum chloride, zinc sulfate, aluminum sulfate, and the like.

5. The acrylic monomer to styrenic monomer ratio as claimed in claims 1 and 2 is 0.05 to 0.5.

6. The acrylic monomer as claimed in claims 1 and 2 has a degree of polymerization of 15 to 150.

7. The ratio of inorganic whiskers to styrenic monomers as claimed in claims 1 and 3 is from 0.05 to 0.25.

8. The ratio of the salt of an amphoteric metal oxide to the dry cation exchange resin as claimed in claims 1 and 4 is from 0.05 to 1.0.

9. The solvents for complexing with amphoteric metal oxides as claimed in claim 1 include: methanol, ethanol, isopropanol, and the like.

10. The temperature at which the amphoteric metal oxide complexes according to claim 1 are complexed is: 60 ℃ to 100 ℃.

11. Types of modified acidic cation exchange resins prepared according to claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 that can be used in catalytic reactions include: ester synthesis, ether synthesis, epoxy compound synthesis, olefin hydration, aldol condensation reaction, and the like.