Please briefly describe the typical process flow and key steps for producing methyl acrylate from acrylic acid and methanol as raw materials.

Please briefly describe the typical process flow and key steps for producing methyl acrylate from acrylic acid and methanol as raw materials.
Answer: The main process flow includes: 1) raw material preparation and pretreatment; 2) Sulfuric acid catalyzed esterification reaction; 3) Distillation separation of methanol and products; 4) Dry, filtered, and distilled for post-treatment. The key steps are to control the esterification reaction conditions (temperature 60-80 ℃, excess methanol) and use vacuum distillation purification.
Analysis: This question tests the complete process flow of producing methyl acrylate by esterification method. It is mainly divided into four key stages: 1 Raw material preparation stage: Purity testing of acrylic acid and methanol is required, and sulfuric acid as a catalyst needs to be accurately measured. Industrial grade raw materials usually require pre-treatment to remove impurities. two Esterification stage: Under the catalysis of sulfuric acid, acrylic acid undergoes esterification reaction with methanol to produce methyl acrylate and water. This reversible reaction requires temperature control between 60-80 ℃ and pushing the equilibrium to the right through excess methanol. The reaction equation is: $CH2=CH-COOH+CH3OH \ rightlefthanons CH2=CH-COOCH3+H2O $3. Separation and purification stage: The reaction mixture is separated by distillation, using vacuum distillation (about 50-60 ℃/20kPa) to avoid product decomposition. Unreacted methanol needs to be separated first before collecting the methyl acrylate fraction. four Post processing stage: The crude product needs to be dried (usually anhydrous sodium sulfate), filtered to remove solid impurities, and if necessary, subjected to secondary distillation to obtain a finished product with a purity of over 99%.

5. Key process points include: concentration control of sulfuric acid catalyst (usually 5-10%), strict explosion-proof measures (methyl acrylate is flammable and explosive), and addition of polymerization inhibitors (such as hydroquinone) to prevent polymerization.