Oxidative dehydrogenation of ethane to ethylene and preparation of multimetallic mixed oxide catalyst for such process

摘要

Oxidative dehydrogenation of light paraffins, such as ethane at moderate temperatures (<500° C.) to produce ethylene without the formation of side products such as acetic acid and/or other oxygenated hydrocarbons is achieved using tellurium-free, multimetallic catalysts possessing orthorhombic M1 phase and other crystalline structures that have an important role for obtaining high performance catalysts for the oxidative dehydrogenation of ethane to ethylene. Such catalysts are prepared using thermal and hydrothermal methods.

主权项

1. A process for the oxidative dehydrogenation of ethane to ethylene, which comprises contacting a feedstock comprising ethane and an oxidizing agent under oxidative dehydrogenation reaction conditions with a tellurium-free, multimetallic mixed oxide solid catalyst having the formula
MoVhSbiOx  (I) wherein, h and i, respectively, are each between 0.001 and 4.0, the ratio i/h is between 0.3 and 10.0, and x represents the number determined by and consistent with the valence requirements of elements present in the multimetallic mixed oxide solid catalyst, said multimetallic mixed oxide solid catalyst having an orthorhombic M1 crystalline phase along with a pseudo-hexagonal M2 crystalline phase and an orthorhombic MoO3 crystalline phase, and one or more additional crystalline phases, wherein a process of preparing said multimetallic mixed oxide solid catalyst comprises: A) a process which comprises forming a tellurium-free mixture of molybdenum, vanadium and antimony metallic precursors and a compound selected from the group consisting of primary amines, secondary amines, tertiary amines, ammonia, tetra-methyl ammonium and hydrazine, and subjecting said tellurium-free mixture to hydrothermal condition at a temperature of 100-200° C. for 6-150 hours to obtain a solid, washing and drying said solid to obtain a dried solid, and thermally activating said dried solid to form a catalyst having the pseudo-hexagonal M2 crystalline phase and the orthorhombic MoO3 crystalline phase in addition to the orthorhombic M1 crystalline phase, wherein said thermally activating includes a first thermal treatment at a temperature from about 150° C. to about 350° C. under an oxidizing, reducing or inert atmosphere for 1-5 hours, and thereafter a second thermal treatment at a temperature from about 150° C. to 700° C. under an oxidizing or inert atmosphere for 1 to 5 hours.