阅读说明：本技术 2,2,4-三甲基-3羟基戊酸甲酯的制备方法、钢结构用水性工业漆及其制备方法 (Preparation method of 2,2, 4-trimethyl-3-hydroxy methyl valerate, water-based industrial paint for steel structure and preparation method of water-based industrial paint ) 是由 卢小松 张世元 姜明秋 王永成 张润赟 于 2019-10-31 设计创作，主要内容包括：本发明涉及有机化合物合成及应用技术领域,具体涉及一种2,2,4-三甲基-3羟基戊酸甲酯的制备方法、钢结构用水性工业漆及其制备方法。本发明的2,2,4-三甲基-3羟基戊酸甲酯的制备方法,包括以下步骤：1)异丁醛在碱性催化剂作用下发生羟醛缩合反应,生成2,2,4-三甲基-3-羟基戊醛；将上述得到的2,2,4-三甲基-3-羟基戊醛与H<Sub>2</Sub>O<Sub>2</Sub>发生氧化反应得到2,2,4-三甲基-3羟基戊酸；<Sup>2</Sup>)将步骤1)制得的2,2,4-三甲基-3羟基戊酸和甲醇在强酸催化剂作用下反应得到2,2,4-三甲基-3羟基戊酸甲酯。本发明的2,2,4-三甲基-3羟基戊酸甲酯的制备方法,反应产物单一,无需进行多步分离,操作简单,同时本发明还提供了一种含有上述2,2,4-三甲基-3羟基戊酸甲酯的钢结构用水性工业漆及其制备方法。(The invention relates to the technical field of synthesis and application of organic compounds, in particular to a preparation method of 2,2, 4-trimethyl-3-hydroxy methyl valerate, an aqueous industrial paint for a steel structure and a preparation method thereof. The preparation method of the methyl 2,2, 4-trimethyl-3-hydroxypentanoate comprises the following steps: 1) isobutyraldehyde is subjected to aldol condensation reaction under the action of an alkaline catalyst to generate 2,2, 4-trimethyl-3-hydroxypentanal; subjecting the above to2,2, 4-trimethyl-3-hydroxypentanal with H 2 O 2 Carrying out oxidation reaction to obtain 2,2, 4-trimethyl-3-hydroxyvaleric acid; 2 ) Reacting the 2,2, 4-trimethyl-3-hydroxypentanoic acid prepared in the step 1) with methanol under the action of a strong acid catalyst to obtain 2,2, 4-trimethyl-3-hydroxypentanoic acid methyl ester. The preparation method of the 2,2, 4-trimethyl-3-hydroxy methyl valerate has the advantages of single reaction product, no need of multi-step separation and simple operation, and simultaneously provides the water-based industrial paint containing the 2,2, 4-trimethyl-3-hydroxy methyl valerate for the steel structure and the preparation method thereof.)

1. A preparation method of 2,2, 4-trimethyl-3-hydroxy methyl valerate is characterized by comprising the following steps:

1) preparation of 2,2, 4-trimethyl-3-hydroxypentanoic acid

Isobutyraldehyde undergoes aldol condensation reaction under the action of an alkaline catalyst to generate 2,2, 4-trimethyl-3-hydroxypentanal, and the reaction formula is as follows:

reacting the obtained 2,2, 4-trimethyl-3-hydroxypentanal with H₂O₂Oxidation takes place to give 2,2, 4-trimethyl-3-hydroxyvaleric acid, the reaction scheme being:

2) preparation of methyl 2,2, 4-trimethyl-3-hydroxypentanoate

Reacting the 2,2, 4-trimethyl-3-hydroxypentanoic acid prepared in the step 1) with methanol under the action of a strong acid catalyst to obtain 2,2, 4-trimethyl-3-hydroxypentanoic acid methyl ester, wherein the reaction formula is as follows:

2. the method for preparing methyl 2,2, 4-trimethyl-3-hydroxypentanoate according to claim 1, wherein in the step 1), the alkaline catalyst is NaOH, KOH, Ca (OH)₂、BA(OH)₂And LiOH, wherein the mass ratio of the isobutyraldehyde to the basic catalyst is 100: 1-3.

3. The method for preparing methyl 2,2, 4-trimethyl-3-hydroxypentanoate according to claim 1, wherein in the step 2), the strong acid catalyst is any one of sulfuric acid, hydrochloric acid and p-toluenesulfonic acid.

4. The method for preparing methyl 2,2, 4-trimethyl-3-hydroxypentanoate according to claim 1, wherein in the step 2), the amount of the strong acid catalyst is 0.2 to 0.5% by weight based on the total weight of the 2,2, 4-trimethyl-3-hydroxypentanoate and methanol, and the mass ratio of the 2,2, 4-trimethyl-3-hydroxypentanoate to the methanol is 1000: 200 to 400.

5. The method for preparing methyl 2,2, 4-trimethyl-3-hydroxypentanoate according to claim 1, wherein in the step 2), the esterification reaction temperature of 2,2, 4-trimethyl-3-hydroxypentanoate and methanol is 50 ℃ to 145 ℃, and the esterification reaction time is 10 hours to 30 hours.

6. The preparation method of methyl 2,2, 4-trimethyl-3-hydroxypentanoate according to claim 1, wherein in the step 2), 2, 4-trimethyl-3-hydroxypentanoate and methanol are mixed, a strong acid catalyst is added, the temperature is raised to 50-60 ℃, the mixture is fully stirred and dissolved to form a mixed solution, the mixed solution is stirred and slowly raised to 60-120 ℃, reflux is started, after 1-3 hours of reflux, the temperature at the bottom of the tower is stably raised to 140-145 ℃, the temperature at the top of the esterification tower is 120-125 ℃, the acid value of the esterification liquid is less than or equal to 4mgKOH/g, the esterification liquid is subjected to reduced pressure distillation to remove the methanol, the methanol is discharged at the top of the tower under the conditions that the temperature at the bottom of the tower is 110-125 ℃, the temperature at the top of the tower is 95-110 ℃, and the vacuum degree is-0.1-0.08 Mpa, the, to obtain the crude product of the 2,2, 4-trimethyl-3-hydroxy methyl valerate.

7. The preparation method of methyl 2,2, 4-trimethyl-3-hydroxypentanoate according to claim 6, characterized by adding alkali liquor to the obtained crude methyl 2,2, 4-trimethyl-3-hydroxypentanoate for alkali washing neutralization, wherein the addition amount of the alkali liquor is 3-10% of that of the crude methyl 2,2, 4-trimethyl-3-hydroxypentanoate, the temperature is 50-80 ℃, the time is 2-8 hours, and then performing primary oil-water separation; washing the oil phase obtained by primary oil-water separation, adding purified water, wherein the addition amount of water is 5-20% of the oil phase obtained by primary oil-water separation, the temperature is 60-95 ℃, the time is 2-6 hours, and then performing secondary oil-water separation; and (3) sequentially passing the oil phase obtained by secondary oil-water separation through a dehydration tower to finally obtain 2,2, 4-trimethyl-3-hydroxy methyl valerate, wherein the temperature of the bottom of the dehydration tower is 95-130 ℃.

8. An aqueous industrial paint containing 2,2, 4-trimethyl-3-hydroxy methyl valerate for a steel structure is characterized by comprising the following components: 400-600 parts of water-based acrylic resin, 1-4 parts of preservative, 1-3 parts of pH regulator, 4-10 parts of film-forming additive 2,2, 4-trimethyl-3-hydroxy methyl valerate, 1-3 parts of defoaming agent, 1-3 parts of thickener, 200-400 parts of filler, 30-100 parts of pigment, 50-100 parts of water, 2-6 parts of wetting agent, 2-6 parts of dispersing agent, 5-20 parts of flash rust inhibitor and 3-8 parts of fumed silica, wherein the 2,2, 4-trimethyl-3-hydroxy methyl valerate is prepared by the preparation method of 2,2, 4-trimethyl-3-hydroxy methyl valerate according to any one of claims 1-7.

9. The aqueous industrial paint containing 2,2, 4-trimethyl-3-methyl hydroxypentanoate for steel structures as claimed in claim 8, wherein the preservative is Kathon preservative, the pH regulator is any one or more of ammonia water, triethylamine or AMP-95, the dispersant is any one of polycarboxylate, sodium polyacrylate or polyether modified dimethyl siloxane, the defoamer is any one of oil-based defoamer, silicone defoamer or emulsion defoamer, the wetting agent is octylphenol polyoxyethylene ether or alkylphenol ethoxy sulfate, the thickener is polyurethane thickener, the filler is any one or more of 2500-mesh calcium bicarbonate, barium sulfate, talcum powder or mica powder, and the pigment is iron oxide red or titanium dioxide.

10. The preparation method of the water-based industrial paint containing the methyl 2,2, 4-trimethyl-3-hydroxypentanoate for the steel structure as claimed in any one of claims 8 or 9, characterized by comprising the steps of adding water into a container, adding a dispersing agent, a wetting agent, a defoaming agent, a film-forming aid, methyl 2,2, 4-trimethyl-3-hydroxypentanoate, a thickening agent and a pH regulator under the condition of stirring speed of 500-600 rpm, slowly adding a filler and a pigment, grinding the materials at a temperature of below 50 ℃ and a fineness of below 30 micrometers, adding a water-based acrylic resin and a preservative, and filtering to obtain the water-based industrial paint for the steel structure.

Technical Field

The invention relates to the technical field of synthesis and application of organic compounds, in particular to a preparation method of 2,2, 4-trimethyl-3-hydroxy methyl valerate, water-based industrial paint containing 2,2, 4-trimethyl-3-hydroxy methyl valerate for a steel structure and a preparation method of the water-based industrial paint.

Background

Steel is an important structural material in modern buildings, a plurality of large exhibition centers, stadiums, airport terminal buildings, television towers and the like all adopt steel structures as main structural forms, and the coating design of the steel structure buildings mainly adopts water-based industrial paint for corrosion prevention of the steel structures; however, the film forming auxiliary agent adopted in the prior water-based industrial paint for steel structures is mainly a composition of dodecyl alcohol ester (2,2, 4-trimethyl-1, 3 pentanediol-monoisobutyrate) and benzyl alcohol and ethylene glycol butyl ether, wherein the dodecyl alcohol ester mainly plays a role in film formation, the benzyl alcohol and the ethylene glycol butyl ether mainly play a role in assisting volatilization, this is mainly due to the fact that the volatilization speed of the dodecyl alcohol ester is relatively slow, and needs to be increased by benzyl alcohol and ethylene glycol butyl ether, but because benzyl alcohol and ethylene glycol butyl ether have relatively large taste and low film forming efficiency, the water-based industrial paint for the steel structure has relatively large taste and high VOC content, therefore, a film-forming assistant with low VOC content, high film-forming efficiency and high volatilization speed needs to be developed, and meanwhile, a water-based industrial paint containing the film-forming assistant for steel structures needs to be developed.

Disclosure of Invention

The invention aims to provide a preparation method of an efficient film-forming aid 2,2, 4-trimethyl-3-hydroxy methyl valerate, an aqueous industrial paint containing 2,2, 4-trimethyl-3-hydroxy methyl valerate for a steel structure and a preparation method of the aqueous industrial paint.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a preparation method of 2,2, 4-trimethyl-3-hydroxy methyl valerate comprises the following steps:

1) preparation of 2,2, 4-trimethyl-3-hydroxypentanoic acid

Isobutyraldehyde undergoes aldol condensation reaction under the action of an alkaline catalyst to generate 2,2, 4-trimethyl-3-hydroxypentanal, and the reaction formula is as follows:

2

reacting the obtained 2,2, 4-trimethyl-3-hydroxypentanal with H₂O₂Oxidation takes place to give 2,2, 4-trimethyl-3-hydroxyvaleric acid, the reaction scheme being:

2) preparation of methyl 2,2, 4-trimethyl-3-hydroxypentanoate

Reacting the 2,2, 4-trimethyl-3-hydroxypentanoic acid prepared in the step 1) with methanol under the action of a strong acid catalyst to obtain 2,2, 4-trimethyl-3-hydroxypentanoic acid methyl ester, wherein the reaction formula is as follows:

in the step 1), the basic catalyst is one or two of NaOH, KOH, Ca (OH)2, BA (OH)2 and LiOH, and the mass ratio of the isobutyraldehyde to the basic catalyst is 100: 1-3.

In the step 2), the strong acid catalyst is any one of sulfuric acid, hydrochloric acid or p-toluenesulfonic acid.

In the step 2), the amount of the strong acid catalyst is 0.2-0.5% of the total weight of the 2,2, 4-trimethyl-3-hydroxyvaleric acid and the methanol, and the mass ratio of the 2,2, 4-trimethyl-3-hydroxyvaleric acid to the methanol is 1000: 200 to 400.

In the step 2), the esterification reaction temperature of the 2,2, 4-trimethyl-3-hydroxypentanoic acid and methanol is 50-145 ℃, and the esterification reaction time is 10-30 hours.

In the step 2), 2, 4-trimethyl-3 hydroxypentanoic acid and methanol are mixed, a strong acid catalyst is added, the temperature is raised to 50-60 ℃, the mixture is fully stirred and dissolved to form a mixed solution, the mixed solution is stirred and slowly raised to 60-120 ℃, reflux is started, after the reflux is carried out for 1-3 hours, the temperature of the tower bottom is stably raised to 140-145 ℃, the temperature of the esterification tower top is 120-125 ℃, the acid value of the esterification liquid is less than or equal to 4mgKOH/g, the esterification liquid is subjected to reduced pressure distillation to remove the methanol, under the conditions that the temperature of the tower bottom is 110-125 ℃, the temperature of the tower top is 95-110 ℃, and the vacuum degree is-0.1-0.08 Mpa, the methanol is discharged from the tower top, and the 2,2, 4-trimethyl-3 hydroxypentanoic acid methyl ester is discharged.

Adding alkali liquor into the obtained 2,2, 4-trimethyl-3-hydroxy methyl valerate crude product for alkali washing neutralization, wherein the addition amount of the alkali liquor is 3-10% of that of the 2,2, 4-trimethyl-3-hydroxy methyl valerate crude product, the temperature is 50-80 ℃, the time is 2-8 hours, and then carrying out primary oil-water separation; washing the oil phase obtained by primary oil-water separation, adding purified water, wherein the addition amount of water is 5-20% of the oil phase obtained by primary oil-water separation, namely 5-20% of the crude product of 2,2, 4-trimethyl-3-hydroxy methyl valerate, the temperature is 60-95 ℃, the time is 2-6 hours, and then performing secondary oil-water separation; the oil phase obtained by secondary oil-water separation, namely the crude product of 2,2, 4-trimethyl-3-hydroxy methyl valerate, sequentially passes through a dehydration tower to finally obtain 2,2, 4-trimethyl-3-hydroxy methyl valerate, wherein the temperature of the bottom of the dehydration tower is 95-130 ℃; the alkali liquor is any one of KOH solution or NaOH solution.

An aqueous industrial paint containing 2,2, 4-trimethyl-3-hydroxy methyl valerate for steel structures comprises the following components: 400-600 parts of water-based acrylic resin, 1-4 parts of preservative, 1-3 parts of pH regulator, 4-10 parts of film-forming additive 2,2, 4-trimethyl-3-hydroxy methyl valerate, 1-3 parts of defoaming agent, 1-3 parts of thickener, 200-400 parts of filler, 30-100 parts of pigment, 50-100 parts of water, 2-6 parts of wetting agent, 2-6 parts of dispersing agent, 5-20 parts of flash rust inhibitor and 3-8 parts of fumed silica, wherein the 2,2, 4-trimethyl-3-hydroxy methyl valerate is prepared by any one of the preparation methods of the 2,2, 4-trimethyl-3-hydroxy methyl valerate.

The preservative is a Kathon preservative, the pH regulator is any one or more of ammonia water, triethylamine or AMP-95 (2-amino-2-methyl-1-propanol), the dispersant is any one of polycarboxylate, sodium polyacrylate or polyether modified dimethyl siloxane, and the defoamer is any one of a mineral oil-based defoamer, an organic silicon defoamer or an emulsion type defoamer.

The wetting agent is any one of octylphenol polyoxyethylene ether or alkylphenol ethoxy sulfate, the thickener is a polyurethane thickener, the filler is any one or more of 2500-mesh heavy calcium, barium sulfate, talcum powder or mica powder, and the pigment is any one of iron oxide red or titanium dioxide.

A preparation method of the water-based industrial paint containing the 2,2, 4-trimethyl-3-hydroxy methyl valerate for the steel structure comprises the following steps of adding water into a container, adding a dispersing agent, a wetting agent, a defoaming agent, a film forming aid 2,2, 4-trimethyl-3-hydroxy methyl valerate, a thickening agent and a pH regulator under the condition that the stirring speed is 500-600 rpm, slowly adding a filler and a pigment, grinding the materials at the temperature of below 50 ℃ and the fineness of below 30 micrometers, adding a water-based acrylic resin and a preservative, and filtering to obtain the water-based industrial paint for the steel structure.

The preparation method of the methyl 2,2, 4-trimethyl-3-hydroxypentanoate has the beneficial effects that:

according to the preparation method of the methyl 2,2, 4-trimethyl-3-hydroxypentanoate, isobutyraldehyde is subjected to aldol condensation reaction under the action of a basic catalyst to generate 2,2, 4-trimethyl-3-hydroxypentanal, and then the 2,2, 4-trimethyl-3-hydroxypentanal and H are subjected to aldol condensation reaction₂O₂Oxidation reaction is carried out to generate 2,2, 4-trimethyl-3 hydroxypentanoic acid, and the high-purity 2,2, 4-trimethyl-3 hydroxypentanoic acid is obtained through recrystallization, the reaction product is single, and no further reaction is neededThe production process is simplified by carrying out multi-step separation, the yield of the 2,2, 4-trimethyl-3-hydroxypentanoic acid is high, reactants and a catalyst are common chemical raw materials, and the production cost is low; and simultaneously, the prepared 2,2, 4-trimethyl-3-hydroxypentanoic acid and methanol are subjected to esterification reaction under the action of a strong acid catalyst to generate 2,2, 4-trimethyl-3-hydroxypentanoic acid methyl ester, the esterification reaction has few side reactions, high reaction rate, complete esterification and no byproduct, and the high-purity 2,2, 4-trimethyl-3-hydroxypentanoic acid methyl ester can be prepared.

In the preparation method of the methyl 2,2, 4-trimethyl-3-hydroxypentanoate, the esterification reaction is stopped when the acid value of the esterification liquid is less than or equal to 0.2mgKOH/g, the esterification reaction is complete, and the yield of the generated methyl 2,2, 4-trimethyl-3-hydroxypentanoate is higher.

According to the water-based industrial paint for the steel structure, 2,2, 4-trimethyl-3-hydroxy methyl valerate is used as a film forming aid, and due to the existence of a pentanoate group in the 2,2, 4-trimethyl-3-hydroxy methyl valerate, compared with an alcohol acid ester group in dodecyl alcohol ester (2,2, 4-trimethyl-1, 3 pentanediol monoisobutyrate), the compatibility of the 2,2, 4-trimethyl-3-hydroxy methyl valerate and an acrylic acid monomer is better, so that the viscosity reduction and plasticization effects of latex particles in the emulsion paint are better, and the film forming efficiency is higher and the volatilization speed is higher at a low temperature state compared with that of the dodecyl alcohol ester, so that the drying speed of a paint film of the water-based industrial paint for the steel structure is higher. And the boiling point of the 2,2, 4-trimethyl-3-hydroxy methyl valerate is 200 ℃, compared with the dodecyl alcohol ester, the boiling point is lower, the volatilization speed is higher, so that the prepared water-based industrial paint for the steel structure has high film forming efficiency, the volatilization speed is higher, and the VOC content is low.

Detailed Description