CN102964243B - The preparation method of sec-Butyl Acetate - Google Patents

Abstract

The invention relates to a preparation method of sec-butyl acetate, which uses refinery C4 fraction to react with acetic acid to generate sec-butyl acetate, and introduces reaction by-product C8 olefins into the reaction materials, and the content of C8 olefins accounts for 5-10% of the mass fraction of the total reaction materials , the total reaction material is the sum of C4 fraction and acetic acid, the total reaction acid alkenes is the molar ratio of n-butene and acetic acid in the C4 fraction 1:0.8-2.0, the reaction temperature is 50-120°C, and the reaction pressure is 1.0-2.0MPa. The advantages of the present invention are: due to the introduction of the reaction by-product C8 olefin in the reaction system, the mutual solubility of the raw material n-butene and acetic acid is increased, thereby increasing the reaction conversion rate, reducing the acid-ene ratio and process energy consumption; The by-product of the reaction is C8 olefins, thereby suppressing the side reaction of n-butene under the action of an acidic catalyst to generate C8 olefins, and improving the selectivity of the reaction to generate sec-butyl acetate.

Description

The preparation method of sec-butyl acetate

technical field

The present invention relates to a synthesis method of organic compounds, specifically a method for synthesizing sec-butyl acetate by reacting the C4 fraction of the refinery with acetic acid, that is, using the high conversion rate of n-butene and low acid-ene ratio in the C4 fraction of the refinery to synthesize The sec-butyl acetate method.

Background technique

Second-butyl acetate is a good organic solvent, which is widely used in nitrocellulose, paint, artificial leather, medicine, ink and plastic industries. The traditional method of producing sec-butyl acetate both at home and abroad is to adopt the batch-type tank reaction, and use sulfuric acid as a catalyst to catalyze the reaction of acetic acid and butanol. Since water is produced simultaneously during the esterification of acetic acid and butanol, water will not only cause the reverse reaction of the esterification reaction (ester hydrolysis reaction), but also cause separation difficulties due to the azeotropy of water and acetic acid, so the current research is mainly focused on acetic acid. And on the direct esterification of butene, as US601807A and US5994578 all report the method for acetic acid and isobutylene esterification production butyl acetate under acidic ion exchange resin catalysis. For the production of sec-butyl acetate, in order to improve the conversion rate of n-butene and the selectivity to the product sec-butyl acetate, the method of high acid-ene ratio is generally adopted. For example, Chinese patents CN10112656A, CN201010166597, and CN101143819A report the synthesis of sec-butyl acetate with C4 raw materials in the range of acid-to-ene ratio of 1.5-3.0. Increasing the ratio of acid to vinyl can increase the reaction conversion rate of n-butene. However, due to the excess of acetic acid, acetic acid must be recovered, and acetic acid is highly corrosive. Therefore, not only a large amount of energy consumption is increased for the recovery of acetic acid, but also higher requirements are put forward for equipment materials. Requirements increase the process flow and high equipment investment.

Contents of the invention

The purpose of the present invention is to overcome the weak point that exists in the prior art, and provide a kind of method with high n-butene and acetic acid conversion rate, low acid ratio synthetic sec-butyl acetate.

The object of the present invention can be realized by the following measures: the preparation method of sec-butyl acetate utilizes refinery C4 cuts and acetic acid to react to generate sec-butyl acetate, introduces reaction by-product C8 olefins in the reaction mass, and the C8 olefin content accounts for the total reaction mass The mass fraction is 5-10%, the total reaction material is the sum of C4 fraction and acetic acid, the molar ratio of n-butene and acetic acid in the C4 fraction is 1:0.8-2.0, preferably the reaction total acid alkene is 1:1.0- 1.5, the reaction temperature is 50-120°C, the preferred reaction temperature is 70-80°C, the reaction pressure is 1.0-2.0MPa, and the preferred reaction pressure is 1.0-1.5MPa.

In the research process of the present invention, it is found that the reaction material contains a small amount of C8 hydrocarbons, which can promote the mutual solubility of the reaction substrate n-butene and acetic acid under the reaction conditions, and greatly increase the collision probability of the reaction substrate n-butene and acetic acid. Significantly increase the reaction conversion rate.

The present invention introduces the reaction by-product C8 olefin into the reaction material, and its content accounts for 5-10% of the mass fraction of the total reaction material (the sum of C4 fraction and acetic acid). Due to the introduction of C8 olefin into the reaction system, the reaction rate is increased and the reaction rate is increased. selectivity, so as to achieve the purpose of producing sec-butyl acetate with low acid-to-ene ratio, high conversion rate and high selectivity.

Compared with the prior art, the present invention has the following advantages:

1. Since the introduction of reaction by-product C8 olefins into the reaction system increases the miscibility of the raw material n-butene and acetic acid, thereby increasing the reaction conversion rate, reducing the acid-ene ratio and process energy consumption;

2. Due to the introduction of reaction by-products C8 olefins into the reaction system, the side reaction of n-butene under the action of an acidic catalyst to superimpose and generate C8 olefins is suppressed, and the selectivity of the reaction to generate sec-butyl acetate is improved.

detailed description

The following 4.1 examples further illustrate the present invention, but do not thereby limit the present invention.

Concrete implementation steps of the present invention are as follows:

The separated reaction by-product C8 olefins are recycled to the esterification reactor, and mixed with the reaction feed C4 fraction and acetic acid as the feed to the esterification reactor, wherein the C8 olefins account for the mass of the total reaction material (the sum of the C4 fraction and acetic acid) 5-10% of the score.

Examples The C4 fraction of the raw material refinery is taken from the MTBE unit of Sinopec Jiujiang Petrochemical Company. 0.20%, butene 13.60%. C8 olefins were obtained from the stacking unit of Sinopec Shijiazhuang Refining and Chemical Company, with a purity of 99% and about 1% C12 olefins.

Example 1

Weigh 90 grams of commercially available macroporous strongly acidic cation exchange resin (model A-35) on a dry basis, and put it into a shell-and-tube reactor equipped with 3 stainless steel tubes with an inner diameter of 10 mm and a length of 80 mm, and the shell pass hot water . The reaction temperature is 70°C, the reaction pressure is 1.5MPa, the refinery C4 fraction and C8 olefins are mixed at a mass ratio of 90:10, the total space velocity is 1.0h-1, and the total feed rate is 90 g/hour; 1:2.0 calculation, the feed amount of acetic acid per hour is 76 grams, and the mass fraction of C8 olefins in the total reaction material is 5.4%. After reacting for 3 hours, gas samples and liquid samples were taken every hour for chromatographic analysis to calculate the C4 conversion rate and reaction selectivity, and the data are listed in Table 1.

Example 2:

Weigh 90 grams of commercially available macroporous strongly acidic cation exchange resin (model A-35) on a dry basis, and put it into a shell-and-tube reactor equipped with three stainless steel tubes with an inner diameter of 10 mm and a length of 80 mm. . The reaction temperature is 70°C, the reaction pressure is 1.0MPa, the refinery C4 fraction and C8 olefins are mixed at a mass ratio of 85:15, the total space velocity is 1.0h-1, the total feed rate is 90 g/hour; the molar ratio of olefinic acid is 1 : Calculated at 1.0, the acetic acid feed rate per hour is 36.3 grams, and C8 olefins account for 10% of the total mass fraction of the reaction. After reacting for 3 hours, gas samples and liquid samples were taken every hour for chromatographic analysis, and the conversion rate of C4 and reaction selectivity were calculated. The data are listed in Table 1.

Example 3:

Weigh 90 grams of commercially available macroporous strongly acidic cation exchange resin (model K-300) on a dry basis, and put it into a shell-and-tube reactor equipped with 3 stainless steel tubes with an inner diameter of 10 mm and a length of 80 mm, and the shell pass hot water . The reaction temperature is 75°C, the reaction pressure is 2.0MPa, the refinery C4 fraction and C8 olefins are mixed at a mass ratio of 85:15, the total space velocity is 1.0h-1, the total feed rate is 90 g/hour; the molar ratio of olefinic acid is 1 : Calculated at 1.5, the acetic acid feed rate per hour is 54.5 grams, and C8 olefins account for 9.3% of the total mass fraction of the reaction. After reacting for 3 hours, gas samples and liquid samples were taken every hour for chromatographic analysis, and the conversion rate of C4 and reaction selectivity were calculated. The data are listed in Table 1.

Example 4:

Weigh 90 grams of commercially available macroporous strongly acidic cation exchange resin (model K-300) on a dry basis, and put it into a shell-and-tube reactor equipped with 3 stainless steel tubes with an inner diameter of 10 mm and a length of 80 mm, and the shell pass hot water . The reaction temperature is 80°C, the reaction pressure is 1.5MPa, the refinery C4 fraction and C8 olefins are mixed at a mass ratio of 90:10, the total space velocity is 1.0h-1, and the total feed rate is 90 g/hour; the molar ratio of olefin to acid: 1 : Calculated at 0.8, the acetic acid feed rate per hour is 30.4 grams, and C8 olefins account for 7.5% of the total mass fraction of the reaction. After reacting for 3 hours, gas samples and liquid samples were taken every hour for chromatographic analysis, and the conversion rate of C4 and reaction selectivity were calculated. The data are listed in Table 1.

Comparative example 1

Weigh 90 grams of commercially available macroporous strongly acidic cation exchange resin (model A-35) on a dry basis, and put them into a shell-and-tube reactor equipped with three stainless steel tubes with an inner diameter of 10 mm and a length of 80 mm. water. The reaction temperature is 70°C, the reaction pressure is 1.5MPa, the total space velocity of C4 in the refinery is 1.0h-1, the total feed amount is 90 g/h; the molar ratio of enoic acid: 1:3.0 is calculated, and the feed amount of acetic acid per hour is 120 grams, the reaction system does not contain C8 olefins. After reacting for 3 hours, gas samples and liquid samples were taken every hour for chromatographic analysis to calculate the C4 conversion rate and reaction selectivity, and the data are listed in Table 1.

Comparative example 2

Weigh 90 grams of commercially available macroporous strongly acidic cation exchange resin (model K-300) on a dry basis, and put them into a shell-and-tube reactor equipped with three stainless steel tubes with an inner diameter of 10 mm and a length of 80 mm. water. The reaction temperature is 80°C, the reaction pressure is 2.0MPa, the total space velocity of C4 in the refinery is 1.0h-1, the total feed amount is 90 g/h; the molar ratio of enoic acid: 1:3.0 is calculated, and the feed amount of acetic acid per hour is 120 grams, the reaction system does not contain C8 olefins. After reacting for 3 hours, gas samples and liquid samples were taken every hour for chromatographic analysis, and the conversion rate of C4 and reaction selectivity were calculated. The data are listed in Table 1.

Table 1: Reaction Data

Example 1 Example 2 Example 3 Example 4 Comparative example 1 Comparative example 2 Reactive acid-to-ene ratio 2.0 1.0 1.5 0.8 3.0 3.0 Reaction material C8 content, % 5.4 10.7 9.3 7.5 0 0 C4 olefin conversion rate, % 88.5 92.4 91.6 75.9 75.43 71.51 Selectivity of sec-butyl acetate, % 99.7 99.8 99.6 99.7 97.24 95.22 C12 content,% not detected not detected not detected not detected 0.33 0.55 Colloid content on the catalyst after 100 hours of reaction, % 0.01 0.01 0.01 0.01 0.42 0.95

Comparing the experimental data of examples and comparative examples in Table 1, it can be seen that: due to the introduction of C8 olefins in the reaction system, under the condition of low acid-ene ratio, the conversion rate of C4 olefins and the selectivity to the target product sec-butyl acetate are both Significantly greater than the reaction results with high acid-to-olefin ratio and no introduction of C8 olefins.

Claims (2)

1. the preparation method of sec-butyl acetate is characterized in that: utilize refinery C4 cut and acetic acid reaction to generate sec-butyl acetate, in reaction mass, introduce reaction by-product C8 olefin, C8 olefin content accounts for 5% of the total mass fraction of reaction -10%, the total reaction material is the sum of C4 fraction and acetic acid, the molar ratio of n-butene to acetic acid in the C4 fraction is 1:0.8-2.0, the reaction temperature is 50-120°C, and the reaction pressure is 1.0- 2.0 MPa. 2. The preparation method of sec-butyl acetate according to claim 1, characterized in that: the reaction total acid alkenes 1:1.0-1.5, the reaction temperature is 70-80°C, and the reaction pressure is 1.0-1.5MP.