Method for Producing MTHPA (MeTHPA)
Methyl tetrahydrophthalic anhydride (MTHPA, MeTHPA) material, which is widely used in industries such as electronic potting and encapsulation, electrical casting, electrical impregnation, insulation composite winding and pultrusion, in the production of MTHPA, while by-product recycling Aene, this product can be used as a raw material for fuels, blending oils and resins, and is very popular.
Process introduction and material balance: high metering tank, and moved into the diene reactor. A quantity of maleic anhydride was added to the molten anhydride and heated to 80°C to completely melt. Turn on the stirring of the diene kettle, heat the double-ene kettle jacket to the reflux of C5, stop the heating, slowly add the molten maleic anhydride into the diene reaction kettle, pay close attention to the temperature and pressure changes, if the temperature and pressure rise high, cooled with jacket cooling water, controlled reaction pressure less than 0.25MPa. After the addition is completed, the mixture is kept at 80°C for 4 hours. After sampling, the reflux valve is closed, the recovery of the C5 valve is started, and the diene kettle is slowly heated to the recovered carbon five steam, and the unreacted carbon five is distilled into the recovery. The C5 is taken up until no pentadiene is recovered, the all valves of the diene kettle are closed, the bottom valve is opened, and the diene is transferred to the isomerization vessel by vacuum.
Heated in a heterogeneous kettle with a heat-conducting oil, added with 500g of phosphoric acid catalyst, heated to 220°C, and kept for 4 hours. After sampling and analysis, the isomer was transferred to a vacuum distillation kettle under vacuum for distillation under reduced pressure. Cut the defective product into the tank, cut the qualified product into the qualified product measuring tank, and transfer the qualified product into the mixing tank with vacuum, and then disassemble the unqualified product under reduced pressure. The polymer produced by vacuum distillation is pressed into the polymer. The car is packed in iron drums or plastic bags.
The cooling water in the workshop and the spray water in the tank area use circulating cooling water. The diene kettle and the frit anhydride kettle are heated using steam, and the heat transfer oil is used for isomerization and distillation under reduced pressure. Safe and environmentally friendly methyl tetrahydrophthalic anhydride (MTHPA, MeTHPA), is a non-dangerous product, but the raw materials used are pentadiene, isoprene Class A, class 2.1 chemical dangerous goods, and maleic anhydride Class 8.1 chemical dangerous goods. Therefore, the production workshop is required to carry out fire and fire management according to Class A dangerous goods. Fireworks are strictly prohibited in the factory area. The internal electrical appliances of the workshop are designed according to the requirements of explosion-proof. The production equipment must have a good electrostatic grounding device and must be equipped with appropriate fire-fighting equipment. The production equipment is in accordance with national regulations. Regular inspection; do a good inspection system during operation to prevent leakage.
In the production process of methyl tetrahydrophthalic anhydride (MTHPA, MeTHPA), no process wastewater is produced, and the cooling water used is recycled. The production process is fully enclosed, no process waste gas and waste water are produced, and the heating system adopts electric heating and steam heat. Net heating. Unreacted recycled C5 produced during the synthesis of diene, which can be sold as a by-product to the petroleum resin industry for use as a raw material or fuel industry; as a fuel in the refining process, it can also be sold as a by-product to the resin industry or to produce waterproof coatings. Used as a raw material. There is no source of significant noise during the production process. Therefore, the production process of methyltetrahydrophthalic anhydride (MTHPA, MeTHPA) products has no adverse impact on the ecological environment.