Application of ultrasonic spraying in preparation of p-cymene by industrial dipentene dehydrogenation

Preparation of p-cymene in a pilot equipment using ultrasonic spraying of raw material industrial dipentene (DP) was studied. By comparison with common spraying, it was found that ultrasonic spraying could improve DP dehydrogenation process. The running temperatures of preheater and spray room were all relative lower (10-25 and 100-150 degrees C). The p-cymene yields in ultrasonic spraying mode were higher with 2.45-6.23% than those in common spraying mode at 210-270 degrees C. The p-cymene yields in ultrasonic spraying mode were higher with 0.31-1.10% than those in common spraying mode at 280-310 degrees C. The yield of p-cymene was up to 99.25% in the condition of reactor temperature 310 degrees C, flow rate of DP 4 L/h, nitrogen flow rate 2 L/min based on Pd/C catalyst and ultrasonic spraying. (C) 2010 Elsevier B.V. All rights reserved.