We would like to introduce you a method to produce methyltetrahydrophthalic anhydride, with pentadiene, isoprene and maleic anhydride as its main raw material. Here is the production method of the liquid methyltetrahydrophthalic anhydride:
1. Transport quantitative pentadiene and isoprene to the high carbon measuring tank by a carbon-five pump, and then transfer them to the diene reactor still;
2. Add certain amount of maleic anhydride to the melted anhydride and heat it up to melt it all at a temperature of 120 to 150 degrees Celsius and a pressure of 2kg/cm2;
3. Open the jacket of the diene kettle and heat it until carbon five reflux occurs. Then stop the heating and slowly add the dissolved maleic anhydride into the diene reaction kettle. At the same time, pay attention to the change of temperature and pressure;
4. Add finished, keep warm for 2-6 hours. After the sampling is qualified, close the return valve, open carbon five recovery valve, and slowly heat the diene kettle until the recycled carbon five is evaporated. Steam the unreacted carbon five into the carbon recovery tank until no recycled pentadiene is distilled. Then close all valves of the diene kettle, open the bottom valve, and move the diene to the isomerization kettle with vacuum;
5. Heat with conduction oil in the isomerization kettle and reduce pressure to distill and remove residual trace pentadiene. Then add the catalyst, heat it to the specified temperature and keep it for 30-60 minutes. After sampling and analysis are qualified, transfer the isomers with vacuum to reduced pressure distillation still going through reduced pressure distillation；
6. Cut the qualified product methyltetrahydrophthalic anhydride into the qualified product measurement tank, move the qualified product with vacuum into the mixing kettle and pack them, and then decompress and re-stream the unqualified product.
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