阅读说明：本技术 一种乙酸丁酯的制备方法 (Preparation method of butyl acetate ) 是由 谭劲富 潘书铭 于 2021-09-16 设计创作，主要内容包括：本发明提供了一种乙酸丁酯的制备方法,原料乙酸、丁醇及回收酯经计量放入酯化釜,在催化剂的作用下,通过蒸汽加热,生成乙酸丁酯和水,并在酯化塔内形成共沸物,从塔顶蒸出,经冷凝冷却后,进入分离器进行分离,经精馏从塔顶组分中分离出醇、水、酯混合物,经过冷凝器冷却后,进入分离器分离,酯相进入精馏缓冲槽,得到的头酯的一部分返回酯化塔,另一部分重回流到精馏塔里；水相进入回收塔,精馏塔底得到酯含量、酸度、水分都合格的成品,经冷却后进入计量槽。所述水相为含有酯和醇的废水,进入回收塔后,经蒸馏分离,从塔顶回收得到一定含量的头酯,头酯返回酯化塔,回收后的废水从塔底排掉。(The invention provides a preparation method of butyl acetate, raw materials of acetic acid, butanol and recovered ester are metered and put into an esterification kettle, under the action of a catalyst, butyl acetate and water are generated by steam heating, an azeotrope is formed in an esterification tower, the azeotrope is evaporated out from the top of the esterification tower, the mixture enters a separator for separation after being condensed and cooled, a mixture of alcohol, water and ester is separated from components at the top of the esterification tower through rectification, the mixture enters the separator for separation after being cooled by a condenser, an ester phase enters a rectification buffer tank, one part of the obtained head ester returns to the esterification tower, and the other part of the obtained head ester refluxes to a rectification tower; the water phase enters a recovery tower, and a finished product with qualified ester content, acidity and moisture is obtained at the bottom of the rectifying tower and enters a metering tank after being cooled. And the water phase is wastewater containing ester and alcohol, and is subjected to distillation separation after entering a recovery tower, head ester with a certain content is recovered from the tower top, the head ester returns to the esterification tower, and the recovered wastewater is discharged from the tower bottom.)

1. A preparation method of butyl acetate comprises the following steps:

1) raw materials of acetic acid, butanol and recovered ester are metered and put into an esterification kettle;

2) under the action of a catalyst, butyl acetate and water are generated by steam heating, an azeotrope is formed in an esterification tower, and the azeotrope is evaporated from the tower top;

3) after condensation and cooling, the mixture enters a separator for separation, one part of the water phase reflows, the other part of the water phase enters a recovery tower to recover the dissolved ester and alcohol, one part of the ester phase reflows to an esterification tower, and the rest of the ester phase enters a crude ester buffer tank for preheating and then enters a rectifying tower;

4) separating out a mixture of alcohol, water and ester from the components at the top of the tower through rectification, cooling the mixture by a condenser, separating the mixture in a separator, feeding an ester phase into a rectification buffer tank, returning one part of the obtained head ester to the esterification tower, and refluxing the other part of the obtained head ester into the rectification tower; the water phase enters a recovery tower;

5) obtaining a finished product with qualified ester content, acidity and moisture at the bottom of the rectifying tower, cooling the finished product and then feeding the cooled finished product into a metering tank;

6) and the water phase is wastewater containing ester and alcohol, and is subjected to distillation separation after entering a recovery tower, head ester with a certain content is recovered from the tower top, the head ester returns to the esterification tower, and the recovered wastewater is discharged from the tower bottom.

2. The preparation method as claimed in claim 1, wherein the temperature T (C) in the esterification tower is 115-125 ℃ and the pressure P (MPa) is 0.2-0.5 MPa.

3. The method according to claim 2, wherein the catalyst is selected from the group consisting of strong-acid macroporous cation exchange resins Amberlyst-15 and Zr (SO)₄)₂/TiO₂Mixture of solid acids, Amberlyst-15 and Zr (SO)₄)₂/TiO₂Is m:1, and the temperature T and the pressure P inside the esterification column satisfy the following relationship, 0.61 ═ m ═ R +9.6 ═ P)/T.

4. The process according to the above claim, wherein R is 95-97 and m is 1.36-1.38.

Technical Field

The invention relates to a preparation method of butyl acetate.

Background

Butyl acetate is an excellent organic solvent and is widely used in nitrocellulose varnishes, as a solvent in the processing of artificial leather, textiles and plastics, and also in the fragrance industry. As a spice, the essence is widely used for preparing essences of banana, pear, pineapple, apricot, peach, strawberry, berry and the like. It can also be used as solvent for natural gum and synthetic resin. The fragrance is used in fruit fragrance type essence, and is suitable for use as head fragrance material with high dispersivity, but less consumption is needed to avoid effect influence caused by single protrusion. Can be used in great amount in edible essences such as apricot, banana, peach, pear, pineapple, raspberry, strawberry, etc. The composite material has excellent organic solvent and excellent dissolving performance on cellulose acetate butyrate, ethyl cellulose, chlorinated rubber, polystyrene, methacrylic resin and various natural resins such as tannin extract, manila gum, dammar resin and the like. The composite material is widely applied to nitrocellulose varnish, is used as a solvent in the processing process of artificial leather, fabrics and plastics, is used as an extracting agent in various petroleum processing and pharmaceutical processes, and is also used for compounding spices and components of various flavoring agents such as apricot, banana, pear, pineapple and the like. The solvent is an excellent organic solvent which can dissolve rosin, polyvinyl acetate, polyacrylate, polyvinyl chloride, chlorinated rubber, gutta-percha, polymethyl methacrylate and the like. The method for synthesizing butyl acetate by using the dried starch and the dried starch mainly has the following defects: 1. concentrated sulfuric acid is used as a catalyst, although the reaction activity is fast, the defects of serious equipment corrosion and more side reactions exist; the water content in the reflux organic phase is high, and the common finished butyl acetate product carries water, thereby wasting the yield of the finished product.

Disclosure of Invention

The invention provides a preparation method of butyl acetate, raw materials of acetic acid, butanol and recovered ester are metered and put into an esterification kettle, under the action of a catalyst, butyl acetate and water are generated by steam heating, an azeotrope is formed in an esterification tower, the azeotrope is evaporated from the top of the esterification tower, the condensed and cooled raw materials enter a separator for separation, a part of a water phase reflows, a part of the water phase enters a recovery tower to recover dissolved ester and alcohol, a part of an ester phase reflows to the esterification tower, the rest of the ester phase enters a crude ester buffer tank for preheating, then enters a rectifying tower, alcohol, water and ester mixtures are separated from components at the top of the tower by rectification, the mixture enters the separator for separation after being cooled by a condenser, the ester phase enters the rectifying buffer tank, a part of obtained head ester returns to the esterification tower, and the other part of the obtained head ester reflows to the rectifying tower; the water phase enters a recovery tower, and a finished product with qualified ester content, acidity and moisture is obtained at the bottom of the rectifying tower and enters a metering tank after being cooled. And the water phase is wastewater containing ester and alcohol, and is subjected to distillation separation after entering a recovery tower, head ester with a certain content is recovered from the tower top, the head ester returns to the esterification tower, and the recovered wastewater is discharged from the tower bottom. The specific scheme is as follows:

a preparation method of butyl acetate comprises the following steps:

1) raw materials of acetic acid, butanol and recovered ester are metered and put into an esterification kettle;

2) under the action of a catalyst, butyl acetate and water are generated by steam heating, an azeotrope is formed in an esterification tower, and the azeotrope is evaporated from the tower top;

3) after condensation and cooling, the mixture enters a separator for separation, one part of the water phase reflows, the other part of the water phase enters a recovery tower to recover the dissolved ester and alcohol, one part of the ester phase reflows to an esterification tower, and the rest of the ester phase enters a crude ester buffer tank for preheating and then enters a rectifying tower;

4) separating out a mixture of alcohol, water and ester from the components at the top of the tower through rectification, cooling the mixture by a condenser, separating the mixture in a separator, feeding an ester phase into a rectification buffer tank, returning one part of the obtained head ester to the esterification tower, and refluxing the other part of the obtained head ester into the rectification tower; the water phase enters a recovery tower;

5) obtaining a finished product with qualified ester content, acidity and moisture at the bottom of the rectifying tower, cooling the finished product and then feeding the cooled finished product into a metering tank;

6) and the water phase is wastewater containing ester and alcohol, and is subjected to distillation separation after entering a recovery tower, head ester with a certain content is recovered from the tower top, the head ester returns to the esterification tower, and the recovered wastewater is discharged from the tower bottom.

Further, the temperature T (DEG C) in the esterification tower is 115-125 ℃, and the pressure P (MPa) is 0.2-0.5 MPa.

Further, the catalyst is a mixture of strong acid macroporous cation exchange resin Amberlyst-15 and Zr (SO4)2/TiO2 solid acid, wherein the mass ratio of Amberlyst-15 to Zr (SO4)2/TiO2 is m:1, and the temperature T and the pressure P in the esterification tower satisfy the following relational expression, wherein 0.61 m ═ (R + 9.6P)/T.

Further, R is 95-97, and m is 1.36-1.38.

The invention has the following beneficial effects:

1) through the process steps, the yield and the selectivity of butyl acetate are high, the products in the process steps are fully utilized for recycling, the operation is simple, and the cost is low;

2) the inventors further found that the corrosion of concentrated sulfuric acid to equipment can be avoided by using a composite catalyst instead of a concentrated sulfuric acid catalyst, and the conversion (%) of acetic acid and the selectivity (%) of butyl acetate are higher than those of concentrated sulfuric acid as a catalyst;

3) further, the inventors have found that when the pressure and temperature in the esterification column are controlled so as to satisfy a specific relational expression for a specific catalyst, the conversion (%) of acetic acid and the selectivity (%) of butyl acetate are very high when 0.61 ═ m (R +9.6 ═ P)/T is satisfied.

Drawings

FIG. 1 is a flow chart of a process for the production of butyl acetate

Detailed Description

The present invention will be described in more detail below with reference to specific examples, but the scope of the present invention is not limited to these examples.

Examples

1) Raw materials of acetic acid, butanol and recovered ester are metered and put into an esterification kettle;

2) under the action of a catalyst, butyl acetate and water are generated by steam heating, an azeotrope is formed in an esterification tower, and the azeotrope is evaporated from the tower top;

3) after condensation and cooling, the mixture enters a separator for separation, one part of the water phase reflows, the other part of the water phase enters a recovery tower to recover the dissolved ester and alcohol, one part of the ester phase reflows to an esterification tower, and the rest of the ester phase enters a crude ester buffer tank for preheating and then enters a rectifying tower;

4) separating out a mixture of alcohol, water and ester from the components at the top of the tower through rectification, cooling the mixture by a condenser, separating the mixture in a separator, feeding an ester phase into a rectification buffer tank, returning one part of the obtained head ester to the esterification tower, and refluxing the other part of the obtained head ester into the rectification tower; the water phase enters a recovery tower;

5) obtaining a finished product with qualified ester content, acidity and moisture at the bottom of the rectifying tower, cooling the finished product and then feeding the cooled finished product into a metering tank;

6) and the water phase is wastewater containing ester and alcohol, and is subjected to distillation separation after entering a recovery tower, head ester with a certain content is recovered from the tower top, the head ester returns to the esterification tower, and the recovered wastewater is discharged from the tower bottom.

The catalyst is a mixture of strong-acid macroporous cation exchange resin Amberlyst-15 and Zr (SO4)2/TiO2 solid acid, wherein the mass ratio m of Amberlyst-15 to Zr (SO4)2/TiO2 is as follows: 1, m is 1.36-1.38, and the amount of the catalyst is 1 wt% of the amount of the alcohol.

The temperature T (DEG C) in the esterification tower is 115-125 ℃, the pressure P (MPa) is 0.2-0.5MPa, and the following relation is satisfied, wherein 0.61-m (R + 9.6-P)/T, and R is 95-97.

Acetic acid conversion (%) - (amount of acetic acid-content of acetic acid in reaction product) ÷ amount of acetic acid × 100%

Selectivity for butyl acetate (%). actual yield of butyl acetate ÷ theoretical yield of butyl acetate × 100%

The experimental data of the examples and comparative examples are shown in Table 1

TABLE 1

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention.