Views:2 Author:Site Editor Publish Time: 2022-01-12 Origin:Site
Throughout the history of Acetic Acid (GAA)CAS 64-19-7 industry, in 1911, the world's first industrial plant for acetaldehyde and acetic acid was built and put into operation in Germany.
In 1960, the high pressure and high temperature carbonylation of methanol to acetic acid developed by BASF company in Germany with methanol as raw material and cobalt as catalyst was industrialized. In 1983, Eastman Company in the United States built an industrial installation of acetic acid-acetic anhydride co-production technology.
In recent years, traditional methanol carbonylation and other processes have been improved, and new processes and technologies emerge in endlessly, thus making the production technology of acetic acid constantly upgrading.
In the early 1970s, more than 50% of acetic acid in the United States and Western Europe was produced with acetaldehyde as raw material, and methanol as raw material acetic acid was less than 15% of the total production. By the early 1990s, the production of acetic acid with methanol as raw material accounted for 50% of the total production, and continued to increase thereafter.
In acetic acid production process, methanol carbonyl synthesis process produces acetic acid with the lowest cost, higher conversion and selectivity. Worldwide, the scale of plants using methanol carbonyl synthesis process to produce acetic acid has greatly increased from less than 50 kT /a in 1960 to more than 1.0Mt/a.
At present, the foreign acetic acid industrial production process mainly includes methanol carbonyl synthesis, acetaldehyde oxidation and butane (light oil) liquid phase oxidation. In terms of production capacity, about 60% is methanol carbonylation, 18% ethylene acetaldehyde oxidation, 10% ethanol acetaldehyde oxidation, 8% butane/naphtha oxidation, and 4% for other methods.
The proportion distribution of various acetic acid processes is shown in the figure below. Copyright @ 6Chem. All Rights Reserved
At present, the preparation process of acetic acid is mainly the carbonylation of methanol, that is, under the action of catalyst, methanol and carbon monoxide react to produce acetic acid; This process accounts for more than 60% and growing share of the global acetic acid production process. BP and Celanese each have proprietary technology for the process, called Cativa and AO Plus, respectively. The Japanese company Chiyoda has recently developed a new process called Acetica, which uses a" bubble Column reactor ". Other commercial processes include: Wacker process, acetaldehyde oxidation to acetic acid, n-butane or naphtha liquid phase oxidation to acetic acid, etc.
Recent development of ethylene, ethane, butene or methane oxidation to acetic acid process: such as Japan showa Electric Company will direct oxidation of ethylene (also known as one-step method) to prepare acetic acid, and achieved commercial; Wacker developed a butene-based route; Sabic has developed an ethane oxidation process using a dedicated catalyst, which is considered feasible only in regions where ethane is cheap. In addition, acetic acid is also byproduct during the production of PVA.
In methanol carbonyl synthesis, Monsanto/BP and Halcon/Eastman are two typical production processes. The former adopts rhodium catalyst, while the latter adopts non-noble metal catalyst system, namely nickel acetate/methyl iodine/tetraphenyltin catalyst. In recent years, two new processes have emerged, namely, Celanese AO Plus process (acid optimization process) and BP Chemicals Cativa process based on iridium catalyst.
In 1970,Monsanto developed a methanol carbonyl synthesis process using rhodium/iodide as catalyst, replacing a high-pressure process catalyzed by cobalt iodide pioneered by BASF in 1960. In 1986, BP acquired the ownership of Monsanto's technology and improved the technology (called the Monsanto /BP process). The acetic acid selectivity (measured in methanol) of the Monsanto /BP process was greater than 99%. The equation is as follows:
C0 + CH3OH CH3COOH + 33Kcal/mal
Rhodium-catalyzed carbonyl synthesis of methanol has high selectivity and can be operated under appropriate pressure (about 3.4MPa). However, due to the high price of rhodium and the complex recovery process, new rhodium and non-rhodium catalysts have been continuously developed. Improvements to the Monsanto /BP process have been made by Celanese (AOPlus Process) and BP (Cativa process). Recently, Japanese Chiyoda company also developed a new acetic acid production process (Acetica process) based on methanol carbonyl synthesis technology. The catalyst systems of the four methanol carbonyl synthesis processes are shown in the table below.