Are there any related to methacrylates (manufacturing process)?

I was taller than polymethacrylate two years ago; first, one needs to prepare methacrylate, and it seems that this substance called “ammonium propylsulfonate” didn’t exist back then. If possible, please send over your process; I’ll see if I can help you. :)

There are mainly three methods for producing methyl methacrylate (MMA): (1) the acetoncyanohydrin method. The ACH method is the earliest industrial method for producing MMA; it was put into industrial use by ICI in 1937, and it remains the most common production process for MMA worldwide. It uses hydrocyanic acid, a by-product of acrylonitrile production, as a raw material; it reacts with propylene to produce propyl cyanohydrin. Propyl cyanohydrin is then treated with concentrated sulfuric acid to yield methacrylamide sulfate, which is subsequently esterified directly with methanol to produce MMA. Through continuous improvement and refinement over a long period of time, this method is advanced in technology, mature and reliable, and produces high-quality products; as a result, it has been widely adopted. Currently, MMA produced using this method accounts for about 80% of the world’s total production. However, this method has serious drawbacks: it involves the use of the highly toxic chemical hydrocyanic acid, and strict protective measures are required during its storage, transportation, and use ； A large amount of waste acid is generated, amounting to 25–35 t/t (MMA) ； Equipment exposed to sulfuric acid corrosion requires the use of corrosion-resistant materials. Therefore, this law is under increasing pressure from environmental protection advocates. (2) Propionaldehyde method: The German company BASF uses this method to produce MMA, and built a plant with a capacity of 36 kt/a in 1988. This method uses ethylene and syngas as raw materials, which react in the presence of a catalyst to produce propionaldehyde; propionaldehyde and formaldehyde then undergo condensation to yield methacrylic acid, which is subsequently esterified with methanol to produce MMA. This process uses readily available raw materials, giving it a certain degree of competitiveness; however, the technology is monopolized by the German company BASF and has never been transferred to others. (3) Isobutylene method (C4 method) In the 1970s, due to a shortage of hydrocyanic acid in Japan, as well as issues related to the disposal of large amounts of wastewater generated by the ACH method and the market for the by-product ammonium sulfate, Japan was forced to turn to developing new MMA synthesis methods using isobutylene derived from the C4 fractions produced as a by-product of ethylene cracking and those obtained from refinery FCC processes, where such resources were more abundant. The isobutylene method is further divided into the two-step gas-phase direct oxidation of isobutylene and the ammoxidation of isobutylene. a. Two-step gas-phase direct oxidation method of isobutylene: Methyl acrylate is produced by two-stage gas-phase catalytic oxidation using isobutylene or tert-butanol as raw materials; the process is similar to that used for the two-stage gas-phase catalytic oxidation of propylene to produce acrylic acid. Under the conditions of the first reaction stage, tert-butanol first undergoes dehydration to form isobutylene; thereafter, isobutylene undergoes catalytic oxidation. Therefore, the catalytic oxidation processes of isobutylene and tert-butanol are essentially the same. Isobutylene is oxidized in the first stage to produce methacraldehyde (MAL); MAL is further oxidized in the second stage to yield methacrylic acid (MAA). After separation and purification, MAA is esterified with methanol to produce MMA. b. Isobutylene amination method: The high cost of raw materials, along with the need to treat waste acid solutions, also increases the costs. This method cannot compete with the direct oxidation of isobutylene, but it remains attractive due to the available idle equipment for the ammoxidation of propylene, as well as the existing equipment from MMA plants using the ACH process. In our country, the production of methyl methacrylate is carried out entirely using the propiononitrile process. However, some manufacturers, due to a lack of raw materials, still employ the outdated sodium cyanide method: sodium cyanide reacts with sulfuric acid to produce hydrocyanic acid, which then reacts with propiononitrile to form ACH, from which MMA is subsequently produced. Due to a severe shortage of propylene cyanohydrin and the impact of imported products, the operating rate of domestic production facilities is very low, with many small and medium-sized enterprises having ceased production. The direct oxidation of isobutylene is a process that offers low costs, minimal pollution, and good economic benefits for the production of MMA. Currently, there is an abundance of C4 resources in the domestic market, yet their utilization rate is low; many companies are seeking ways to make use of them. Therefore, given the actual conditions of the domestic market, it is feasible and promising to build MMA production facilities using isobutylene as a raw material.

? This post was last edited by qingqing02 on 2008-4-11 10:13.]

Are you going to make methacrylate or methyl methacrylate?

Is it you who wants to work with PMMA?