阅读说明：本技术 一种木焦油固化剂的制备方法 (Preparation method of wood tar curing agent ) 是由 聂宁 王文博 刘晓杰 肖进彬 于 2020-07-16 设计创作，主要内容包括：本发明提供了一种木焦油固化剂的制备方法,属于涂料技术领域。本发明提供的制备方法,包括以下步骤：将脱水木焦油、碱性溶液和乙醇混合后,滴加氯仿,进行reimer-tiemann反应,得到reimer-tiemann反应产物；将所述reimer-tiemann反应产物依次进行溶解、酸化、减压蒸馏、萃取有机馏分和抽提有机相,得到富醛基油；将所述富醛基油和二甲苯混合,得到富醛基油的二甲苯溶液；将木焦油、碳酸氢钠和水混合进行酸碱中和反应,分液提取有机相后,进行减压蒸馏,得到木焦酚油；将所述木焦酚油、丙烯酸、多乙烯多胺和二甲苯混合后,滴加所述富醛基油的二甲苯溶液,进行曼尼希反应,得到木焦油固化剂。(The invention provides a preparation method of a wood tar curing agent, belonging to the technical field of coatings. The preparation method provided by the invention comprises the following steps: mixing the dehydrated wood tar, an alkaline solution and ethanol, and then dropwise adding chloroform to perform reimer-tiemann reaction to obtain a reimer-tiemann reaction product; sequentially dissolving, acidifying, distilling under reduced pressure, extracting organic fractions and extracting an organic phase from the reimer-tiemann reaction product to obtain aldehyde-rich oil; mixing the aldehyde-rich base oil and xylene to obtain a xylene solution rich in aldehyde base oil; mixing wood tar, sodium bicarbonate and water, carrying out acid-base neutralization reaction, separating liquid, extracting an organic phase, and carrying out reduced pressure distillation to obtain wood tar oil; and mixing the wood tar oil, acrylic acid, polyethylene polyamine and xylene, and then dropwise adding the xylene solution rich in aldehyde-based oil to perform Mannich reaction to obtain the wood tar curing agent.)

1. A preparation method of a wood tar curing agent comprises the following steps:

1) mixing the dehydrated wood tar, an alkaline solution and ethanol, and then dropwise adding chloroform to perform reimer-tiemann reaction to obtain a reimer-tiemann reaction product;

2) sequentially dissolving, acidifying, distilling under reduced pressure, extracting organic fractions and extracting an organic phase from the reimer-tiemann reaction product to obtain aldehyde-rich oil;

3) mixing the aldehyde-rich base oil and xylene to obtain a xylene solution rich in aldehyde base oil;

4) mixing wood tar, sodium bicarbonate and water, carrying out acid-base neutralization reaction, separating liquid, extracting an organic phase, and carrying out reduced pressure distillation to obtain wood tar oil;

5) mixing the wood tar oil, acrylic acid, polyethylene polyamine and xylene, and then dropwise adding the xylene solution rich in aldehyde-based oil to perform Mannich reaction to obtain a wood tar curing agent;

the temperature of the reduced pressure distillation in the step 4) is 110-150 ℃, and the pressure is 0.085-0.1 MPa;

steps 1) to 3) and step 4) are not in chronological order.

2. The preparation method according to claim 1, wherein the reimer-tiemann reaction is carried out at a temperature of 40 to 90 ℃ for 1 to 2 hours, and the time is measured from the beginning of dropwise addition of chloroform.

3. The method according to claim 1, wherein the dropwise addition rate of chloroform is 1 to 2 drops/min.

4. The method according to claim 1, wherein the mixing in step 1) is carried out at a temperature of 50 to 75 ℃ for 10 to 30 min.

5. The preparation method according to claim 1, wherein the mass ratio of the dehydrated wood tar, the alkaline solution, the ethanol and the chloroform is 40-80: 190-250: 50-60: 70-100 parts; the molar concentration of the alkaline solution is 9-13.5 mol/L.

6. The method according to claim 1, wherein the Mannich reaction is carried out at a temperature of 40 to 90 ℃ for 1 to 2 hours, based on the addition of the aldehyde-rich base oil.

7. The method according to claim 1, wherein the mixing in step 5) is carried out at a temperature of 55 to 95 ℃ for 1 to 3 hours.

8. The preparation method according to claim 1, wherein the mass ratio of the wood pyrogallol oil, the acrylic acid, the polyethylene polyamine, the xylene and the aldehyde-rich base oil is 30-50: 10-20: 30-50: 30-60: 50-65 parts; the mass of the xylene is the sum of the mass of the xylene in the step 3) and the mass of the xylene in the step 5).

9. The method according to claim 1 or 8, wherein the volume ratio of the xylene in the step 3) to the xylene in the step 5) is 1-2: 1.

10. The method according to claim 1, wherein the dropping of the xylene solution rich in aldehyde-based oil is carried out at a rate of 1 to 3 drops/min.

Technical Field

The invention belongs to the technical field of coatings, and particularly relates to a preparation method of a wood tar curing agent.

Background

The wood tar is a black sticky liquid with strong pungent smell, contains phenolic substances, is often used as a raw material for preparing a curing agent, and is synthesized into the phenolic aldehyde amine epoxy resin curing agent through a Mannich reaction. The phenolic aldehyde amine epoxy resin curing agent is widely used due to the advantages of low viscosity, small relative molecular mass, good compatibility with various types of epoxy resins, strong wetting property, high curing speed, convenient construction and the like, and belongs to non-toxic fine chemical products.

The Chinese invention patent CN 102702483A discloses a wood tar modified epoxy resin curing agent, a production method thereof and an epoxy resin anticorrosive paint, wherein the curing agent is a phenol-aldehyde amine curing agent prepared by carrying out Mannich reaction on refined wood tar fraction in wood tar, formaldehyde and polyethylene polyamine. The refined wood tar fraction is obtained by carrying out reduced pressure distillation on wood tar under the conditions that the pressure is 0.085-0.1 MPa and the temperature is 123-140 ℃, the phenolic content of the refined wood tar fraction is 39.6%, but the phenolic product is lost in the reduced pressure distillation process, so that the distillation yield is only about 20%, and the utilization efficiency of the wood tar is low.

Disclosure of Invention

In view of this, the invention aims to provide a preparation method of a wood tar curing agent, which can improve the utilization efficiency of wood tar.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a preparation method of a wood tar curing agent, which comprises the following steps:

1) mixing the dehydrated wood tar, an alkaline solution and ethanol, and then dropwise adding chloroform to perform reimer-tiemann reaction to obtain a reimer-tiemann reaction product;

2) sequentially dissolving, acidifying, distilling under reduced pressure, extracting organic fractions and extracting an organic phase from the reimer-tiemann reaction product to obtain aldehyde-rich oil;

3) mixing the aldehyde-rich base oil and xylene to obtain a xylene solution rich in aldehyde base oil;

4) mixing wood tar, sodium bicarbonate and water, carrying out acid-base neutralization reaction, separating liquid, extracting an organic phase, and carrying out reduced pressure distillation to obtain wood tar oil;

5) mixing the wood tar oil, acrylic acid, polyethylene polyamine and xylene, and then dropwise adding the xylene solution rich in aldehyde-based oil to perform Mannich reaction to obtain a wood tar curing agent;

the temperature of the reduced pressure distillation in the step 4) is 110-150 ℃, and the pressure is 0.085-0.1 MPa;

steps 1) to 3) and step 4) are not in chronological order.

Preferably, the temperature of the reimer-tiemann reaction is 40-90 ℃, the time is 1-2 h, and the time is measured by dropwise adding chloroform from the beginning.

Preferably, the dropping speed of the chloroform is 1-2 drops/min.

Preferably, the mixing temperature in the step 1) is 50-75 ℃, and the mixing time is 10-30 min.

Preferably, the mass ratio of the dehydrated wood tar to the alkaline solution to the ethanol to the chloroform is 40-80: 190-250: 50-60: 70-100 parts; the molar concentration of the alkaline solution is 9-13.5 mol/L.

Preferably, the temperature of the Mannich reaction is 40-90 ℃ and the time is 1-2 h, wherein the time is counted by adding the aldehyde-rich base oil from the beginning.

Preferably, the mixing temperature in the step 5) is 55-95 ℃ and the mixing time is 1-3 h.

Preferably, the mass ratio of the wood pyrogallol oil, the acrylic acid, the polyethylene polyamine, the xylene and the aldehyde-rich base oil is 30-50: 10-20: 30-50: 30-60: 50-65 parts; the mass of the xylene is the sum of the mass of the xylene in the step 3) and the mass of the xylene in the step 5).

Preferably, the volume ratio of the xylene in the step 3) to the xylene in the step 5) is 1-2: 1.

Preferably, the speed of dripping the xylene solution rich in aldehyde-based oil is 1-3 drops/min.

The preparation method provided by the invention comprises the following steps: 1) mixing the dehydrated wood tar, an alkaline solution and ethanol, and then dropwise adding chloroform to perform reimer-tiemann reaction to obtain a reimer-tiemann reaction product; 2) sequentially dissolving, acidifying, distilling under reduced pressure, extracting organic fractions and extracting an organic phase from the reimer-tiemann reaction product to obtain aldehyde-rich oil; 3) mixing the aldehyde-rich base oil and xylene to obtain a xylene solution rich in aldehyde base oil; 4) mixing wood tar, sodium bicarbonate and water, carrying out acid-base neutralization reaction, separating liquid, extracting an organic phase, and carrying out reduced pressure distillation to obtain wood tar oil; 5) mixing the wood tar oil, acrylic acid, polyethylene polyamine and xylene, and then dropwise adding the xylene solution rich in aldehyde-based oil to perform Mannich reaction to obtain a wood tar curing agent; the temperature of the reduced pressure distillation in the step 4) is 110-150 ℃, and the pressure is 0.085-0.1 MPa; steps 1) to 3) and step 4) are not in chronological order. According to the invention, dehydrated wood tar, alkaline solution, ethanol and chloroform are used as raw materials to carry out reimer-tiemann reaction, aldehyde group is introduced to phenolic hydroxyl group of phenolic substance (such as heterocyclic hydroxyl compound such as hydroxyl furan, hydroxyl pyrrole, hydroxyl indene, hydroxyl naphthalene and the like) in the wood tar to obtain o-hydroxybenzaldehyde, so that the utilization rate of the phenolic component in the wood tar is improved, when the prepared curing agent is mixed with epoxy resin, the content of macromolecular organic matters in the coating can be increased, the solid content is improved after crosslinking, meanwhile, the oxygen-containing heterocycle in the curing agent can increase the oxygen content in the coating, and the oxidation resistance of the coating is improved. In the invention, sodium bicarbonate can perform acid-base neutralization reaction with organic acid in the tar to generate organic sodium salt, most of the organic sodium salt without benzene rings can be retained in a water phase through liquid separation, the adverse effect of the organic acid on a reduced pressure distillation product is greatly reduced, the wood tar oil (comprising phenol, methyl phenol, ethyl phenol and methoxyphenol) with high phenol content is obtained, wherein the content of phenolic substances reaches 42%, and the utilization rate of the wood tar is effectively improved. In the invention, the comprehensive utilization of the wood tar is as high as 85-90%.

According to the invention, the formaldehyde-rich oil prepared by reimer-tiemann reaction replaces formaldehyde conventionally adopted in the prior art to prepare the curing agent, so that the prepared curing agent does not contain free formaldehyde, the problem of emission of free formaldehyde contained in the curing agent in the prior art is solved, the pollution to the environment is reduced, and the problems of large coating brittleness, incomplete curing, unstable coating shrinkage force and easiness in foaming caused by the formaldehyde contained in the curing agent in the prior art are solved.

Moreover, the wood tar curing agent prepared by the invention is a polycyclic branched chain curing agent, and can greatly enhance the air tightness of the coating after being crosslinked with epoxy resin, reduce the porosity, effectively prevent chemical substances and microorganisms from passing through and improve the corrosion resistance of the coating. According to the invention, the acrylic acid is added into the raw materials, so that the toughness and the bending property of the coating can be improved.

Detailed Description

The invention provides a preparation method of a wood tar curing agent, which comprises the following steps:

1) mixing the dehydrated wood tar, an alkaline solution and ethanol, and then dropwise adding chloroform to perform reimer-tiemann reaction to obtain a reimer-tiemann reaction product;

2) sequentially dissolving, acidifying, distilling under reduced pressure, extracting organic fractions and extracting an organic phase from the reimer-tiemann reaction product to obtain aldehyde-rich oil;

3) mixing the aldehyde-rich base oil and xylene to obtain a xylene solution rich in aldehyde base oil;

4) mixing wood tar, sodium bicarbonate and water, carrying out acid-base neutralization reaction, separating liquid, extracting an organic phase, and carrying out reduced pressure distillation to obtain wood tar oil;

5) and mixing the wood tar oil, acrylic acid, polyethylene polyamine and xylene, and then dropwise adding the xylene solution rich in aldehyde-based oil to perform Mannich reaction to obtain the wood tar curing agent.

In the present invention, unless otherwise specified, the starting materials used are all those conventionally available commercially in the art or those prepared by methods well known to those skilled in the art.

The method comprises the steps of mixing dehydrated wood tar, alkaline solution and ethanol, then dropwise adding chloroform, and carrying out reimer-tiemann reaction to obtain a reimer-tiemann reaction product.

In the present invention, the wood tar is preferably prepared from agricultural and forestry waste through cracking. The specific operation mode of the cracking is not particularly limited in the present invention, and the cracking mode known to those skilled in the art can be adopted. In the invention, the wood tar can effectively solve the problem of utilization of the wood tar generated in the biomass pyrolysis energy industry, and develops a new application value for high-value application of the wood tar.

In the present invention, the dehydrated wood tar is preferably obtained by dehydrating wood tar by means of reduced pressure distillation (hereinafter referred to as first reduced pressure distillation). In the invention, the pressure of the first reduced pressure distillation is preferably 0.085-0.1 MPa, and more preferably 0.09-0.095 MPa; the temperature of the first reduced pressure distillation is preferably 65-70 ℃; the time of the first reduced pressure distillation is preferably 20-40 min.

In the invention, the mass ratio of the dehydrated wood tar, the alkaline solution, the ethanol and the chloroform is preferably 40-80: 190-250: 50-60: 70 to 100, more preferably 60 to 65: 215 to 225: 55-58: 82-87, more preferably 65: 220: 55: 85. in the present invention, the alkaline solution preferably includes NaOH solution, KOH solution, Na₂CO₃Solution, K₂CO₃Solutions, LiOH solutions or Ba (OH)₂A solution; the molar concentration of the alkaline solution is preferably 9-13.5 mol/L, and more preferably 11-11.5 mol/L. In the present invention, the ethanol is preferably anhydrous ethanol.

In the invention, the mixing temperature is preferably 50-75 ℃; the mixing time is preferably 10-30 min.

In the invention, the dripping speed of the chloroform is preferably 1-2 drops/min. The method ensures the chloroform and the wood tar to fully react by dripping the chloroform.

In the invention, the temperature of the reimer-tiemann reaction is preferably 40-90 ℃, and more preferably 65-72 ℃; the time of the reimer-tiemann reaction is preferably 1-2 h, and the time of the reimer-tiemann reaction is preferably measured by dropwise adding chloroform from the beginning.

After the reimer-tiemann reaction, the obtained reimer-tiemann reaction product is preferably refluxed, and the refluxing time is preferably 0.5-1 h. The obtained reimer-tiemann reaction product is refluxed, so that the purity of the reimer-tiemann reaction product can be improved.

According to the invention, dehydrated wood tar, alkaline solution, ethanol and chloroform are used as raw materials to carry out reimer-tiemann reaction, aldehyde group is introduced to phenolic hydroxyl group of phenolic substance (such as heterocyclic hydroxyl compound such as hydroxyl furan, hydroxyl pyrrole, hydroxyl indene, hydroxyl naphthalene and the like) in the wood tar to obtain o-hydroxybenzaldehyde, so that the utilization rate of the phenolic component in the wood tar is improved, when the prepared curing agent is mixed with epoxy resin, the content of macromolecular organic matters in the coating can be increased, the solid content is improved after crosslinking, meanwhile, the oxygen-containing heterocycle in the curing agent can increase the oxygen content in the coating, and the oxidation resistance of the coating is improved.

After obtaining the reimer-tiemann reaction product, the reimer-tiemann reaction product is sequentially subjected to dissolution, acidification, reduced pressure distillation, organic fraction extraction and organic phase extraction to obtain the aldehyde-rich base oil.

In the invention, the reimer-tiemann reaction product is preferably cooled, and then is sequentially subjected to dissolution, acidification, reduced pressure distillation (hereinafter referred to as second reduced pressure distillation), organic fraction extraction and organic phase extraction to obtain the aldehyde-rich base oil. The cooling method of the present invention is not particularly limited, and a cooling method known to those skilled in the art may be used. In the present invention, the dissolution is preferably carried out in anhydrous ethanol. The using amount of the absolute ethyl alcohol is not specially limited, and the reimer-tiemann reaction product can be dissolved. In the invention, the acidification is preferably carried out in hydrochloric acid, and the molar concentration of the hydrochloric acid is preferably 1-3 mol/L. The use amount of the hydrochloric acid is not specially limited, and the pH value of a product obtained after dissolution can be acidified to 1-3. In the embodiment of the invention, the volume ratio of the hydrochloric acid to the absolute ethyl alcohol is preferably 1: 1. In the invention, the temperature of the second reduced pressure distillation is preferably 60-65 ℃; the pressure of the second reduced pressure distillation is preferably 0.085-0.1 MPa. According to the invention, ethanol and water in the product obtained after acidification are removed through second reduced pressure distillation. In the present invention, the extraction is preferably carried out in diethyl ether. The invention removes salt impurities and water in the product obtained after acidification by extraction. In the present invention, the extraction is preferably performed by Soxhlet extraction. The invention recovers the ether by extraction.

After obtaining the aldehyde-rich oil, the invention mixes the aldehyde-rich base oil with xylene to obtain a xylene solution rich in aldehyde base oil. The mixing mode is not particularly limited, and the raw materials can be uniformly mixed.

The method comprises the steps of mixing wood tar, sodium bicarbonate and water, carrying out acid-base neutralization reaction, carrying out liquid separation, extracting an organic phase, and then carrying out reduced pressure distillation (hereinafter referred to as third reduced pressure distillation) to obtain the wood pyrogallol oil.

In the present invention, the mixing order is preferably that sodium bicarbonate and water are mixed to obtain a sodium bicarbonate solution, and then the sodium bicarbonate solution is mixed with wood tar to perform an acid-base neutralization reaction. In the invention, the mass concentration of the sodium bicarbonate solution is preferably 4-9%. If the mass concentration of the sodium bicarbonate solution is too low, the acid-base neutralization reaction is not complete; if the mass concentration is too high, unreacted sodium bicarbonate will remain in the oil phase, and the subsequent distillation process will decompose sodium carbonate to react with the phenolic substances. The mixing mode is not particularly limited, and the wood tar, the sodium bicarbonate and the water can be uniformly mixed. The liquid separation method is not particularly limited in the present invention, and a liquid separation method known to those skilled in the art may be used. The organic phase and the water phase are obtained through liquid separation. In the invention, sodium bicarbonate can generate acid-base neutralization reaction with organic acid in tar to generate organic sodium salt, most of the organic sodium salt without benzene rings can be kept in a water phase through liquid separation, the adverse effect of the organic acid on a reduced pressure distillation product is greatly reduced, the phenol content in the wood pyrogallol oil is favorably improved, and a small amount of organic acid sodium salt containing benzene rings is kept in heavy components through distillation.

In the invention, the temperature of the third reduced pressure distillation is 110-150 ℃, preferably 120-140 ℃, and more preferably 125-135 ℃; the pressure of the third reduced pressure distillation is 0.085-0.1 MPa, and preferably 0.09-0.095 MPa.

In order to understand the properties and the structure of the heavy fraction in the wood pyrogallol oil, the element analysis is carried out on the heavy fraction obtained under the conditions that the pressure of the third reduced pressure distillation is 0.09MPa and the temperature of the third reduced pressure distillation is 150 ℃, and the analysis data are shown in Table 1.

TABLE 1 results of elemental analysis of heavy fraction

Analysis of the experimental data in Table 1 suggests that the average molecular formula of the heavy fraction is C_15.3H_10.2O₅N_0.2。

From C_15.3H_10.2O₅N_0.2The structural model shows that the heavy fraction contains a large amount of unsaturated bonds, has stronger polarity, can be mixed with various resins, can be effectively embedded in the coating polymer of the coating, and enhances the plasticity and the oxidation resistance of the coating. In the present invention, the components of the heavy fraction obtained under other temperature conditions are similar to those of the heavy fraction obtained under the condition of 150 ℃, and are not repeated herein.

The method comprises the step of carrying out third reduced pressure distillation on the wood tar at the temperature of 110-150 ℃ and under the pressure of 0.085-0.1 MPa to obtain the wood tar oil (comprising phenol, methyl phenol, ethyl phenol, methoxy phenol and the like) with high phenol content, wherein the content of phenolic substances reaches 42%, and the utilization rate of the wood tar is effectively improved.

After obtaining the wood tar oil, acrylic acid, polyethylene polyamine and xylene (hereinafter referred to as first xylene) are mixed, and then the xylene solution rich in aldehyde base oil is dripped to carry out Mannich reaction, so as to obtain the wood tar curing agent.

In the invention, the mass ratio of the wood pyrogallol oil, the acrylic acid, the polyethylene polyamine, the xylene and the aldehyde-rich base oil is preferably 30-50: 10-20: 30-50: 30-60: 50 to 65, more preferably 37 to 42: 15-17: 37-42: 37-43: 56-60, more preferably 40: 16: 40: 42: 58. in the present invention, the xylene in the aldehyde-rich base oil xylene solution adds a second xylene. In the present invention, the mass of xylene is preferably the sum of the masses of the first xylene and the second xylene; the mass ratio of the first xylene to the second xylene is preferably 1-2: 1. In the invention, acrylic acid and hydroxyl can generate graft copolymerization reaction, and acrylic ester is grafted to the surface of the curing agent, thereby effectively improving the toughness of the coating.

In the invention, the mixing temperature is preferably 55-95 ℃, more preferably 65-75 ℃, and more preferably 68-72 ℃; the mixing time is preferably 1-3 h.

In the present invention, the rate of the addition of the xylene solution rich in aldehyde-based oil is preferably 1 to 3 drops/min.

In the invention, the temperature of the Mannich reaction is preferably 40-90 ℃, more preferably 60-75 ℃, and more preferably 62-70 ℃; the time of the Mannich reaction is preferably 1 to 2 hours, and the time of the Mannich reaction is preferably calculated from the beginning of dropwise addition of the aldehyde-rich base oil.

After the Mannich reaction is finished, the obtained crude Mannich reaction product is preferably refluxed for 1-3 h. The Mannich reaction product obtained by the method is refluxed, so that the purity of the Mannich reaction product can be improved.

According to the invention, the formaldehyde-rich oil prepared by reimer-tiemann reaction replaces formaldehyde conventionally adopted in the prior art to prepare the curing agent, so that the prepared curing agent does not contain free formaldehyde, the problem of emission of free formaldehyde contained in the curing agent in the prior art is solved, the pollution to the environment is reduced, and the problems of large coating brittleness, incomplete curing, unstable coating shrinkage force and easy bubble occurrence caused by the formaldehyde contained in the curing agent in the prior art are solved. The wood tar curing agent prepared by the invention is a polycyclic branched chain curing agent, and can greatly enhance the air tightness of the coating after being crosslinked with epoxy resin, reduce the porosity, effectively prevent chemical substances and microorganisms from passing through and improve the corrosion resistance of the coating.

After the mannich reaction, the mannich reaction product is preferably subjected to fourth reduced pressure distillation to obtain the wood tar curing agent.

In the invention, the temperature of the fourth reduced pressure distillation is preferably 55-65 ℃, and more preferably 60 ℃; the pressure of the fourth reduced pressure distillation is preferably 0.09-0.1 MPa. According to the invention, the moisture in the Mannich reaction product is removed through fourth reduced pressure distillation.

In the invention, when the wood tar curing agent is used, the mass ratio of the wood tar curing agent to the epoxy resin is preferably 1: 1-2. The source of the epoxy resin is not particularly limited in the invention, and the epoxy resin anticorrosive paint which is generally sold in the field can be adopted. E44 epoxy is preferred in embodiments of the present invention.

The following examples are provided to illustrate the preparation of the curing agent for wood tar of the present invention, but they should not be construed as limiting the scope of the present invention.