Seeking advice on the technology for producing vinyl acetate via ethylene oxidation

I can’t understand your question, so I can’t help you.

It refers to the process of producing vinyl acetate via the gas-phase method using ethylene. The principle behind this process is that, under the action of a palladium-based catalyst, ethylene and acetic acid react in a reactor to form vinyl acetate, namely C2H4 + CH3COOH + 1/2 O2 → CH3COOCH2CH3 + H2O. At the end of the 1960s, the German company Bayer-Hoechst and the American company USI successfully developed industrial-scale production techniques for vinyl acetate using the gas-phase method based on ethylene. In the early 1990s, BP (now known as BP Amoco) began working on research related to the production of vinyl acetate using the gas-phase method. It developed the advanced Leap process for manufacturing vinyl acetate in a fluidized bed configuration, and by the end of 2000 it put this technology into use to build an industrial plant with an annual capacity of 250,000 tons in Hull, in northern England. Bayer technology, USI technology, Leap technology, and VAntageTM technology are four vinyl acetate production methods that have very similar processes, yet each one is protected by its own patents.

Thank you so much for the help from the expert on the third floor; thanks!

What was said on the third floor is great; I learned another trick.

Sinopec Shanghai Petrochemical Co., Ltd. possesses the relevant technology; you can consult them as follows； Importing from abroad is also an option: handshake

Sinopec Shanghai Petrochemical Co., Ltd. has technology: lol :lol

At present, the technologies of Sinopec Shanghai are not available for external transfer. Are there any technologies that are available for transfer abroad?

Which foreign company can transfer the ethylene process technology? Could you provide their contact information? Thank you in advance! :lol

Please contact me at wangzch2006@yahoo.com.cn:victory:

Our company has this technology; we can discuss it! The processes currently used in China are all Bayer technologies, and that patent had expired before 1990! And no patent has been applied for in the domestic market! This post was last edited by shiyijp on 2009-1-7 10:41]

2.2 Ethylene method: In this method, ethylene and acetic acid are vaporized and then fed into a fixed-bed reactor equipped with precious metal (Pd-Au) or Pt catalysts, as well as potassium acetate as a co-catalyst. There, they react with oxygen at temperatures of 100–200°C and pressures of 0.6–0.8 MPa. The resulting mixture, which contains a certain proportion of products, is condensed to recover crude vinyl acetate; this crude product is then purified using techniques such as distillation, ultimately yielding pure vinyl acetate. The ethylene process is primarily a gas-phase process. The ethylene process technology is widely used due to its favorable overall technical and economic indicators, and some major companies continue to improve and enhance it in terms of catalysts and process technology. 2.2.1 Ethylene liquid-phase method: In 1960, Mor~ceeB from the former Soviet Union (whose Russian name cannot be typed here) and others published a research report claiming that VAc could be produced by using palladium chloride and sodium acetate in an ice-acetic acid solution, with ethylene introduced under pressure; the mixture was then sealed and left to stand overnight. Subsequently, companies such as ICI in the UK and Hoechst in Germany began research on this topic and obtained patents respectively, with the ICI method being the most representative. Companies such as the British ICI and the Japanese Tokuyama have successively built industrial plants using this method. Due to the presence of chloride ions in the catalyst system used in this process, which causes severe corrosion to the equipment, the plant can only operate for 2-3 years. In 1969, ICI shut down the production facilities for this chemical, and other companies also ceased production or halted construction. This law has been phased out. 2.2.2 Ethylene gas-phase method 2.2.2.1 Bayer and USI methods Since the method for synthesizing VAc directly from ethylene through oxidation was developed, companies such as Bayer, Hoechst, and the American company USI have carried out industrial research related to the fixed-bed gas-phase method. In 1968, the first ethylene vapor-phase Bayer process plant was put into operation in Japan, and in 1972, the ethylene vapor-phase USI process plant was also successfully commissioned. The vapor-phase ethylene method is gradually becoming the main production method for VAc. The Bayer process, jointly developed by Bayer and Hoechst, has a production capacity of over 50 kt/year per reactor. At present, the vast majority of new installations worldwide use this process. Its technical and economic indicators are also continuously being optimized and improved. The USI process was developed by USI, a subsidiary of the American company National Distillers, using a Pd—Pt/A12O3 catalyst. Few manufacturers use this method; the entire process is divided into synthesis and purification stages, and it is basically similar to the Bayer process. Since its introduction, the fixed-bed VAc production technology using the gas-phase ethylene method has been widely applied. However, from the perspectives of reaction kinetics and catalyst deactivation mechanisms, this technology still has many shortcomings, such as continuous catalyst deactivation, uneven distribution of the reactor bed, and a limited one-pass conversion rate of ethylene. 2.2.2.2. BP Amoco’s Leap process: Addressing the shortcomings of the aforementioned fixed-bed production technology for ethylene via the gas phase, BP Amoco improved upon the traditional processes and successfully developed a new one. In 1998, BP Amoco developed the Leap process for producing VAc via a fluidized-bed gas-phase method. In 2001, a 250 kt/year fluidized-bed VAc plant using the Leap process was put into operation in the HuL region of the UK; a feature of this process is the use of a fluidized-bubbling reactor along with continuous removal and replenishment of catalyst, which reduces the capital investment required for the plant by 30%. The process operates at 152°C and 0.9 MPa, with one-pass conversion rates of 8.3%, 30.3%, and 41.25% for ethylene, oxygen, and acetic acid respectively. Based on ethylene, the overall yield of VAc was 96.6% ； 91.3% on an oxygen basis. The space-time yield of the catalyst is 1858–2774 g/L·h, which is significantly higher than that of the fixed-bed process (700–1200 g/L·h). The Leap process developed by BP Amoco utilizes a newly designed fluidized bed reactor system. Compared with the fixed-bed process, the fluidized-bed process has the following advantages. (1) The operation of the fluidized bed allows for the continuous removal of deactivated catalyst, and the catalyst and promoter are continuously and evenly mixed within the reactor, thereby ensuring the catalyst’s performance ； (2) The reactor is cooled using the latent heat of vaporization of the liquid, which allows the heat generated during the reaction to be removed promptly, thereby minimizing catalyst deactivation caused by overheating ； (3) This cooling method for the reactor eliminates the need for a distillation tower and heat exchangers required in a fixed-bed system, thereby saving substantial capital investment in equipment. 2.2.2.3. Celanese’s VAntage process: Celanese also improved upon the traditional fixed-bed production technology using ethylene in the gas phase, and in 2001 it successfully developed a new fixed-bed VAntage process. Although this process also uses fixed-bed technology, it overcomes the shortcomings of traditional fixed-bed processes thanks to significant improvements in the catalyst system, as well as a new technique for recovering ethylene from the exhaust gases. The VAntage process also uses a palladium catalyst system, but employs substances such as potassium citrate as reducing agents and silica gel as a support to produce metal catalyst particles with a particle size of 20 nm. Additionally, lanthanide rare earth elements such as praseodymium and neodymium are incorporated into the Pd/Au/K catalyst, thereby enhancing the catalyst’s activity and selectivity and resulting in a higher space-time yield; this allows the production capacity of existing fixed-bed reactors to be increased by 10% to 15%. Based on a comprehensive analysis, the VAntage process can reduce production costs by 2% to 8%. When this technology is used to expand existing fixed-bed installations, the investment required is only 10% to 15% of the investment needed to build new installations of the same scale. After using this process to upgrade a 190 kt/a plant in Singapore, Celanese increased its production capacity by 22% without any additional investment. Additionally, the Celanese Nanjing plant with a capacity of 300,000 t/a, which came online in August 2008, uses this process as well.

Our company is currently seeking process technologies for the production of vinyl acetate via the ethylene route; please feel free to contact me so that we can discuss technology transfer or other forms of cooperation. My email: tzmfg@sina.com

The most advanced ethylene process technologies at present are Amoco’s Leap process and Celanese’s Vantage process.