Study on Reaction Mechanism and Process Safety for Epoxidation

Area of Science:

• Chemical Engineering
• Process Safety
• Organic Chemistry

Background:

• Epoxidation reactions are vital in synthesizing various chemical compounds.
• High steric olefinic compounds present unique challenges in reaction control and safety.
• Understanding reaction mechanisms and thermal behavior is critical for safe industrial scale-up.

Purpose of the Study:

• To investigate the reaction mechanism and process safety of epoxidation using a sterically hindered olefin.
• To quantify the exothermic nature of the epoxidation reaction and assess heat accumulation.
• To determine the decomposition kinetics and identify thermal safety concerns.

Main Methods:

• Utilized online Raman spectroscopy and high-performance liquid chromatography (HPLC) for real-time process monitoring.
• Quantified reaction heat using calorimetry, measuring apparent reaction heat and heat conversion rate.
• Conducted decomposition kinetics studies to determine thermal stability and temperatures of maximum reaction rate.

Main Results:

• The epoxidation process is significantly exothermic, with an apparent reaction heat of 1340.0 kJ·kg^-1.
• A substantial heat conversion rate of 39.7% was observed early in the reaction, indicating rapid heat accumulation.
• The reaction mechanism involves rapid formation of maleic acid peroxide followed by a slower, kinetically controlled reaction with triazolenes.
• Decomposition temperatures were determined: T_D24 = 89.9 °C and T_D8 = 104.1 °C.

Conclusions:

• The epoxidation of triazolene with hydrogen peroxide presents considerable safety concerns due to significant exothermicity and heat accumulation.
• The reaction pathway is controlled by hydrogen peroxide feeding and subsequent kinetic steps, influencing process safety.
• Knowledge of decomposition kinetics is essential for establishing safe operating temperature limits and preventing runaway reactions.