Discussion on downstream products of methanol

I hope everyone can identify the main downstream products of methanol, so that we can conduct more in-depth discussions and encourage thorough exchanges among us!

I think dimethyl ether is worth considering. What do everyone think?

Dimethyl ether, formaldehyde – please recommend a few key ones that could be prioritized for development

:Handshake: There are likely many types of downstream products derived from methanol, such as dimethyl ether, formaldehyde, acetic acid, olefins, propylene, and so on. The key is to determine it based on the actual conditions of the factory. :handshake :handshake

Can someone talk about PTA and acetic acid? I hope to see content in this area.

BP is the world’s largest supplier of acetic acid, with 70% of global acetic acid production utilizing BP’s technology. In 1996, BP filed a patent for the Cativa technology. The Cativa process utilizes a new catalyst system based on iridium, along with various new additives such as rhenium, ruthenium, and osmium. The iridium-based catalyst system is more active than rhodium-based catalysts, produces fewer by-products, and can operate at low water concentrations (less than 5%). This allows it to **improve the traditional methanol carbonylation process, reducing production costs by up to 30% and cutting expansion costs by 50%**. Furthermore, as the water concentration decreases, the efficiency of CO utilization improves, and steam consumption is reduced. ■ Celanese AO Plus process – Celanese is also one of the world’s largest producers of acetic acid. In 1978, the Hearst-Selanis Company (now Celanese Corporation) put the Monsanto process acetic acid plant into commercial operation at Lake Claire in Texas, United States. In 1980, Syngenta introduced a patented technology called the AO Plus method (Acid Optimization Method), **which improved the Monsanto process. The AO Plus process enhances the stability of the rhodium catalyst by adding a high concentration of inorganic iodine, primarily lithium iodide. After the addition of lithium iodide and iodomethane, the water concentration in the reactor is reduced to 4%~5%, yet the rate of carbonylation reaction remains very high, thereby significantly reducing the separation costs associated with the process. The change in catalyst composition enabled the reactor to operate at low water concentrations (4%–5%), thereby increasing the yield of the carbonylation reaction as well as the efficiency of separation and purification. The main advantages of the AO Plus process are high yields and reduced investment and utility costs. However, it is prone to corrosion in high-iodine environments, and the residual iodine content in the final product is high; the high iodine concentration in the acetic acid product can cause catalyst poisoning in downstream applications, such as in the production of vinyl acetate. To address this issue, Selenis developed the Silverguard process to remove trace amounts of iodine impurities from acetic acid; using silver metal ion exchange resins, the iodine content can be reduced to less than 2PPb, whereas with traditional methods the iodine content is typically around 10PPm. Seralis has also introduced polymer resins containing metal salts, which can react with halide impurities in halide-containing solutions to form precipitates. The new method is characterized by the ability to effectively remove halide impurities in one step, eliminating the need for additional distillation and recovery steps. ■ Chiyoda’s Acetica process: UOP and Chiyoda Corporation have also developed a methanol carbonylation process that uses a multiphase support catalyst system and a bubble column reactor. Chiyoda Corporation developed the Acetica process in 1997, using methanol and CO as raw materials as well. By combining a multiphase rhodium (Rd) catalyst with polyvinylpyridine resin, and using iodomethane as a promoter, this supported catalyst system is said to offer high production efficiency, improve the management of rhodium, and enable an acetic acid yield of over 99%. The Monsanto process is a conventional technique for producing acetic acid; it involves the synthesis of acetic acid from methanol and CO in a stirred-tank reactor at approximately 175 ℃ and 2.8 MPa, with a liquid rhodium-based composite catalyst and iodine compounds dissolved in the reaction mixture. Chiyoda Corporation’s Acetica process operates under similar reaction conditions, but it is carried out in a bubble column closed-loop reactor using a suspended, solid rhodium-based composite catalyst supported on special material spheres. After the reaction, the product is flashed and dehydrated, and then purified by distillation; the methanol conversion rate exceeds 99%.

Currently, the main production technologies for acetic acid in foreign countries include the methanol carbonylation method, the acetaldehyde oxidation method, and the n-butane/light oil oxidation method. The acetaldehyde oxidation method is further divided into the ethylene oxidation method, the acetylene method, and the ethanol oxidation method, with the liquid-phase oxidation of ethylene being the most common approach. According to statistics, over 70% of acetic acid production in the world today is carried out using the low-pressure methanol carbonylation method. The main production processes in the low-pressure carbonylation of methanol include the Mosanto/BP process, the Halcon/Eastman acetic anhydride process, Celanese’s AO process, and the Southwest Chemical Engineering Institute process, among others.

It depends on the synthesis method and route you use; different synthesis methods and process conditions will result in different by-products