阅读说明：本技术 一种用微通道反应器制备乙酸乙烯酯的方法 (Method for preparing vinyl acetate by using microchannel reactor ) 是由 杨琳 熊磊 张存浩 邹倩 冷梅 董灿生 张国宾 于 2019-11-12 设计创作，主要内容包括：本发明公开了一种用微通道反应器制备乙酸乙烯酯的方法,包括如下步骤：向乙酸中加入催化剂,混合均匀得到悬浮液,通入微通道反应器,同时乙烯、氧气一起通入所述微通道反应器,控制微通道反应器温度,反应,将微通道反应器出口的产物通过冷凝装置进行收集,得到含有未反应原料的气体和含有催化剂的液体,含有催化剂的液体分离出催化剂后蒸馏得到乙酸乙烯酯,含有未反应原料的气体作为循环气通入所述微通道反应器。本发明采用连续操作的通过微通道反应器,反应时间从传统的数小时缩短到几十秒至几分钟,显著提高了反应效率。本发明可加强传质、传热性能,保持反应温度恒定,避免飞温现象,减少副产物的产生,同时提高了反应过程的安全性。(The invention discloses a method for preparing vinyl acetate by using a microchannel reactor, which comprises the following steps: adding a catalyst into acetic acid, uniformly mixing to obtain a suspension, introducing the suspension into a microchannel reactor, introducing ethylene and oxygen into the microchannel reactor, controlling the temperature of the microchannel reactor, reacting, collecting a product at an outlet of the microchannel reactor by a condensing device to obtain gas containing an unreacted raw material and liquid containing the catalyst, separating the catalyst from the liquid containing the catalyst, distilling to obtain vinyl acetate, and introducing the gas containing the unreacted raw material into the microchannel reactor as a circulating gas. The invention adopts a microchannel reactor which is operated continuously, the reaction time is shortened from traditional hours to dozens of seconds to several minutes, and the reaction efficiency is obviously improved. The invention can strengthen the mass transfer and heat transfer performance, keep the reaction temperature constant, avoid the temperature runaway phenomenon, reduce the generation of by-products and simultaneously improve the safety of the reaction process.)

1. A process for the production of vinyl acetate using a microchannel reactor, comprising the steps of: adding a catalyst into acetic acid to enable the final mass content of the catalyst to be 1% -10%, uniformly mixing to obtain a suspension, introducing the suspension into a microchannel reactor at a flow rate of 8-18g/min, simultaneously introducing ethylene into the microchannel reactor at a flow rate of 10-25g/min and oxygen at a flow rate of 3-5g/min, controlling the temperature of the microchannel reactor to be 100-220 ℃, reacting for 80-300 s, collecting a product at an outlet of the microchannel reactor through a condensing device to obtain gas containing unreacted raw materials and liquid containing the catalyst, separating the catalyst from the liquid containing the catalyst, distilling to obtain vinyl acetate, and introducing the gas containing the unreacted raw materials into the microchannel reactor as a circulating gas.

2. The method according to claim 1, wherein the microchannel structure of the microchannel reactor is a tubular structure of a straight-flow type, a reinforced hybrid type T-shaped structure, a spherical baffled structure, a drop-shaped structure, or a heart-shaped structure.

3. The method according to claim 1, characterized in that the catalyst is a supported bimetallic catalyst Pd-Pt/Al₂O₃The particle size is 1-10 μm.

4. The process of claim 1 wherein the microchannel reactor temperature is from 110 to 160 ℃.

5. The method of claim 1, wherein the reaction time is 120s to 200 s.

Technical Field

The invention belongs to the technical field of organic synthesis application, and particularly relates to a method for preparing vinyl acetate by using a microchannel reactor.

Background

Vinyl Acetate (VAC), also known as vinyl acetate, is an important organic chemical feedstock. Vinyl acetate can be formed into products of polyvinyl alcohol (PVA), vinyl acetate-ethylene copolymer (EVA), polyvinyl acetate (PVAC), vinyl acetate-vinyl chloride copolymer (EVC), and the like by self-polymerization or copolymerization with other monomers. These products are very versatile and can be used in general in adhesives, sizing agents for paper or textiles, paints, inks, leather processing, emulsifiers, water-soluble films, soil conditioners, etc.

In general, vinyl acetate production routes include both ethylene and acetylene processes. Worldwide, ethylene process production is currently predominant. The ethylene-process vinyl acetate production process is characterized in that raw materials of ethylene, oxygen and acetic acid gas are fed into a reactor to contact with a catalyst, and react at the pressure of 0.5-1.4MPa (gauge pressure) and the temperature of 130-220 ℃ to generate VAC, water and a small amount of byproducts, and the high-temperature reaction gas enters a gas separation device after being subjected to multi-stage cooling and condensation so as to achieve the purpose of gas-liquid separation. Unreacted ethylene gas is returned to the compressor. The condensed acetic acid and VAC mixed liquid is sent to a rectification process to carry out VAC purification.

Microchannel reaction equipment has a range of properties not found in conventional reactors: the device has the advantages of miniaturized channel size, larger heat exchange specific surface area, excellent mass and heat transfer characteristics, continuous reaction, capability of skipping direct amplification through a step-by-step amplification test, flexible production and high safety performance.

To date, no report has been made on the production of vinyl acetate by the ethylene process using microchannel reactors.

Disclosure of Invention

A process for making vinyl acetate with a microchannel reactor comprising the steps of: adding a catalyst into acetic acid to enable the final mass content of the catalyst to be 1% -10%, uniformly mixing to obtain a suspension, introducing the suspension into a microchannel reactor at a flow rate of 8-18g/min, simultaneously introducing ethylene into the microchannel reactor at a flow rate of 10-25g/min and oxygen at a flow rate of 3-5g/min, controlling the temperature of the microchannel reactor to be 100-220 ℃, reacting for 80-300 s, collecting a product at an outlet of the microchannel reactor through a condensing device to obtain gas containing unreacted raw materials and liquid containing the catalyst, separating the catalyst from the liquid containing the catalyst, distilling to obtain vinyl acetate, and introducing the gas containing the unreacted raw materials into the microchannel reactor as a circulating gas.

The microchannel structure of the microchannel reactor is a straight-flow tubular structure, and a mixed T-shaped structure, a spherical baffle structure, a water-drop structure or a heart-shaped structure is enhanced.

The catalyst is preferably a supported bimetallic catalyst Pd-Pt/Al₂O₃The particle size is 1-10 μm.

The temperature of the microchannel reactor is preferably 110-160 ℃.

The reaction time is preferably 120s to 200 s.

The invention has the advantages that:

1. the invention adopts a microchannel reactor which is operated continuously, the reaction time is shortened from traditional hours to dozens of seconds to several minutes, and the reaction efficiency is obviously improved.

2. The adopted reaction equipment microchannel reactor can enhance the mass transfer and heat transfer performance, keep the reaction temperature constant, avoid the temperature runaway phenomenon, reduce the generation of by-products and simultaneously improve the safety of the reaction process.

Drawings

FIG. 1 is a flow diagram of a process for preparing vinyl acetate using a microchannel reactor according to the present invention.

FIG. 2 is a diagram of a typical structural unit of a microchannel reactor module used in the present invention; (A) a reinforced mixed T-shaped structure, (B) a spherical structure, (C) a spherical baffle structure and (D) a drop structure; (E) a heart-shaped structure.

Detailed Description

The present invention will be further illustrated by the following specific examples, but the present invention is not limited to the following examples.