Patent ID: 6458971
Filing Date: 2002-10-01
Classification: C07C

Abstract:
A process for the preparation of maleic anhydride which comprises subjecting an aliphatic hydrocarbon having four or more carbon atoms to gas phase oxidation reaction in the presence of a catalyst, wherein supposing that the function of reaction product gas composition is FL and the function of temperature and pressure of reaction product gas is FR, the safety index F satisfies the following relationship (1):F=FLâˆ’FR>0â€ƒâ€ƒ(1) whereinFL represents the value calculated by the following equation (2): â€ƒFL=C/CT/COâ€ƒâ€ƒ(2)whereinC represents the concentration (vol %) of flammable gas in the reaction product gas, supposing that various flammable gases in the reaction product gas are numbered, 1, 2, 3, . . . , i, . . . n, respectively, and the concentration (vol %) of various flammable gases are C1, C2, C3, . . . , Ci, . . . , Cn, respectively, C can be calculated from the equation C=&Sum;i=1n&it;Ci;CO represents the oxygen gas concentration (vol %) in the atmosphere meaning the concentration of oxygen gas in the gas obtained by removing flammable gas from all the gases, which can be calculated from the equation Co={Concentration (vol %) of oxygen in the reaction product gas/(100-C)}Ã—100; andCT represents the stoichiometric flammable gas concentration (vol %) meaning the concentration of flammable component at which flammable gases in the reaction gas can be completely combusted with oxygen contained in the reaction product gas, supposing that the ratio of the stoichiometric amounts of oxygen to the amounts of each flammable component required for complete combustion are R1, R2, R3, . . . Ri, . . . , Rn, respectively, CT can be calculated from the following equation: CT=100/[1+{(&Sum;i=1n&it;(RixCi)/&Sum;i=1n&it;Ci)/Co}Ã—100]â€ƒand FR represents the value calculated by the following equation (3) FR=2.319Ã—10âˆ’5Ã—T2âˆ’1.688Ã—10âˆ’2T+3.288+(Pâˆ’0.15)Ã—0.3â€ƒâ€ƒ(3) â€ƒwhereinT represents the temperature (Â°C.) of reaction product gas; and P represents the reaction pressure (MPaG).