The Thermal Rearrangement Of Monoterpenes

The mechanisms of thermal rearrangements of monoterpenoids, namely a-pinene, β-pinene, and pinane are investigated respectively; the processes of thermal rearrangements of the three compounds are summarized and the kinetic data were worked out. A new kind of fluidized bed reactor was designed based on the thermal rearrangement theory, and the dynamical regime of fluid flow was studied. The results are as follows:The parallel products of thermal rearrangement of a-pinene are limonene and ocimene of which selective ratio is54:42(±1), meanwhile the ocimene are rearranging to allo-ocimene rapidly of which control step is the rearrangement of a-pinene, the highest yield of allo-ocimene was47%. Myrcene, limonene and psi-limonene are the parallel products of β-pinene rearrangement and the highest yield of the myrcene is82.6%.The principal product of the pinane is dihydromyrcene of which highest yield is67.5%. As the possibility of the consecutive reaction of the principal products, the percent conversion must be degraded for promoting the selectivity.The results of the apparent kinetic parameters by means of thermal rearrangements of above-mentioned monoterpenoids in the flow-type reactors respectively are hollow pipe,06mm steel balls fixed pipe,03mm steel balls fixed pipe and fluidized bed reactors show that by increasing of the area to volume ratio, the apparent active energy, apparent rate factor, apparent active enthalpy and apparent active entropy are all increased and close to their intrinsic reaction kinetics finally. Adding small fluidized particle can also promote the reaction yield.The new kind of fluidized bed reactor for thermal rearrangement was designed. Preliminary experiments show the novel reactor has the advantages of1-2%higher yield than fixed bed reactor for myrcene, and decreased reaction temperature almost20℃, and has self-clean function.On the basis of presented theory of particle bed fluidity mechanics, a more detailed flow physical model was proposed and a flow mechanics calculation model was obtained combined with the theory of fluidization in this study. The concept of fluidized particle resident rate was proposed following the cold experiment and brings up the pressing drop correlation in reactor. A simulated calculation of the reactor was completed combined with thermal conduction model for large scale porous media and the reaction kinetic equations.The commercial-scale quenching process was presented for depressing the side reaction at high temperature combined macroporous draining plate with random packing type of cooling tower to resolve coking, scaling and blocking in condensing heat exchanger. Finally,100kg/h scale industrial process and equipments were designed and the piping&instrument diagram, the calculation specification for key equipment and process conditions were also included.