Identification of Significant Process Safety Risks in the Preparation of Methyl-N-cyanocarbamate

The evaluation of the manufacturing route to prepare a process intermediate, methyl-N-cyanocarbamate, revealed a significant process safety risk. A single credible process maloperation can trigger a large exotherm, and a large amount of gas would be released that could cause the reactor to overpressurize and fail. The chemistry involves the reaction of methyl chloroformate with an aqueous cyanamide solution at a controlled temperature and pH. The process was thoroughly evaluated using calorimetry and gas quantitation to understand its thermal and pressure behavior. This paper describes the commercial background and process safety characterization of the process and the steps taken to understand and mitigate the risks. This paper details several “what if” scenarios (i.e., process deviations) that could lead to hazardous situations. One credible “what if” scenario was identified as particularly dangerous as it could result in a runaway reaction and is described in detail.