Process Intensification Of Catalytic Oxidation Of A-isophorone To 4-ketoisophorone In A Rotating Packed Bed Reactor

As an important intermediate for the synthesis of vitamin E,oxoisophorone(KIP)can be produced by oxidation of isophorone.There are two main methods for the synthesis of KIP.The first one is isomerizingα-isophorone(α-IP)into β-isophorone(β-IP),and then to oxidize β-IP into KIP.The second synthesis method is direct-oxidation of α-IP to KIP.However,in the first method,due to the stable chemical properties of α-IP,the isomerization of α-IP into β-IP requires a high reaction temperature and high energy consumption.The conversion rate is also low.In the second method,the reaction time required to produce KIP by oxidation of α-IP is long and the conversion of oxidation of β-IP is lower than that of β-IP.A rotating packed bed(RPB)is an efficient gas-liquid and liquid-liquid mass transfer and mixing device,which has been widely used in separation and reaction process intensification in chemical industry.On the basis of the research,oxidizing α-IP to KIP in the RPB will realize the progress and development of preparation KIP by α-IP.The main results are shown as follows:(1)Using NHPI as catalyst to oxidize α-IP without solvent in the condition of STR,the effects of reaction time,reaction temperature,oxygen flow rate,and catalyst amount on the conversion rate and yield were studied.The optimal operating conditions were determined as:STR rotation speed of 600 r·min-1,oxygen flow rate of 40 L·h-1,reaction temperature of 60℃,reaction time of 4 h,and NHPI of 5 mol%.(2)Using RPB to oxidize α-IP without solvent.The effects of RPB rotation speed,reaction time,reaction temperature,oxygen flow rate,liquid flow rate,and catalyst amount on the reaction conversion and yield were investigated.The optimal operating conditions were determined as:RPB rotation speed of 800 r·min-1,STR rotation speed of 600 r·min-1,reaction temperature of 60℃,oxygen flow rate of 20 L·h-1,liquid flow rate of 20 L·h-1,NHPI of 5 mol%.After 1 h of reaction under this condition,the conversion can reach 24.28%and the selectivity is 73.81%.(3)Using RPB+STR to oxidize α-IP without solvent.The optimal operating conditions were determined as:RPB rotation speed of 800 r·min-1,STR rotation speed of 600 r·min-1,reaction temperature of 60℃,oxygen flow rate of 20 L·h-1,liquid flow rate of 20 L·h-1,NHPI of 5 mol%.After 1h of reaction under this condition,the conversion can reach 26.69%and the selectivity is 72.68%.Compared RPB+STR to RPB under the optimal operating conditions,the conversion and yield has a significant improvement,but the selectivity has a decrease,which shows that the catalytic oxidation ofα-IP to KIP mainly happened in the RPB.