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Section 7 Methyl Formate Methyl formate (methylformate) has the molecular formula HCOOCH and is a colorless, flammable and scented liquid. The traditional production method of methyl formate is the esterification of formic acid and methanol. However, due to backward technology, large consumption of formic acid, and serious equipment corrosion, it has been gradually eliminated. Since the 1980s, methanol carbonylation and methanol dehydrogenation production routes for methyl formate have been successfully developed, which has significantly reduced the production cost of methyl formate and has become the main method for producing methyl formate. 1. Properties and uses of methyl formate. Methyl formate molecules contain methyl, methoxy, hydroxyl and ester groups. Therefore, methyl formate has active chemical properties and can undergo many chemical reactions. Methyl formate molecules contain methyl, methoxy, hydroxyl and ester groups. Therefore, methyl formate has active chemical properties and can undergo many chemical reactions. 3. Matters needing attention in the production process: Ø The methanol and carbon monoxide used as raw materials should be free of impurities such as water, oxygen and CO2 to prevent the catalyst from forming sodium formate and sodium bicarbonate through the reaction, causing deactivation of the catalyst and causing fouling and clogging of the reactor. ； Ø Since the raw material carbon monoxide contains inert gas and unreacted carbon monoxide is recycled, in order to maintain the carbon monoxide partial pressure required for the reaction and prevent the accumulation of inert gas, part of the gas coming out of the top of the reactor must be discharged. ； Ø The bottom distillate of the methyl formate product tower contains methanol and catalyst. Insoluble and inactive catalyst must be removed before recycling. 4. Reactor operating conditions and catalyst reactor operating conditions: Temperature 80℃, pressure 4.5MPa. Due to the exothermic reaction, the reaction mixture was cooled using external circulation. The single-pass conversion rate of methanol is 30%, and the single-pass conversion rate of carbon monoxide can reach 95%. This method consumes 560 kg of methanol (90%) and 562 m3 of carbon monoxide (standard temperature and pressure) per ton of methyl formate produced. catalyst: The only industrial catalyst for the carbonylation of methanol to produce methyl formate is sodium methoxide (CH3ONa). The advantage is high selectivity, with methyl formate being the only product. However, the one-way catalyst system composed of sodium methoxide has serious shortcomings. It is particularly sensitive to H2O and CO2 contained in the raw material methanol and CO, and a small amount of H2O and CO2 can deactivate the catalyst. Section 8 Low-carbon olefins Low-carbon olefins usually refer to olefins with carbon atoms ≤ 4, such as ethylene, propylene and butylene. Its traditional production method is through naphtha cracking. In recent years, the technology for synthesizing olefins using natural gas as raw material has become increasingly mature and is gradually being industrialized. The following are three types of methods for producing light olefins from natural gas: Methanol to olefins is a process that uses coal or natural gas as raw materials to produce low-carbon olefins such as ethylene and propylene through methanol. It is a very attractive and most promising process to replace the naphtha route to produce olefins. Thermodynamic data: 3. Catalyst The key technology in the MTO synthesis process is the catalyst. Since a large amount of water exists in the reaction, and the catalyst needs to be frequently regenerated at a higher temperature to burn carbon during operation, the thermal stability and hydrothermal stability of the catalyst are the decisive factors affecting its chemical life. In the past, ZSM-5 and its modified products were mostly used, but in recent years, they have tended to use silicoaluminophosphate molecular sieves (SAPO), especially the small-pore SAPO-34 with a strong selectivity 8-ring channel, which has shown good activity and selectivity. Operating conditions of UOP/Hydro MTO process Ø The operating temperature is 350~525℃, preferably 350℃, and the operating pressure is 0.2~0.4 MPa ； Ø Control product selectivity by comprehensively adjusting material throughput, temperature, pressure and catalyst circulation rate ； Ø The increase in reaction temperature and pressure will significantly increase the number of hydrocarbons above C5, so MTO must choose a lower reaction temperature and pressure. ； Ø As the reaction time increases, the reaction products tend to become heavier, and low-carbon olefins are converted into aromatics and hydrocarbons above C5. The reaction requires a higher space velocity. ； Ø Adding diluent to the methanol raw material of MTO can improve the selectivity of ethylene.