# Thermal Risk Evaluation of the Fluorobenzotriazolone Nitration Process

## TL;DR

This paper evaluates the thermal risks involved in a chemical process used to make a synthetic intermediate for pyraclostrobin, identifying key safety concerns and suggesting mitigation strategies.

## Contribution

The study provides a detailed thermal risk evaluation of the fluorobenzotriazolone nitration process, including raw material and product decomposition risks.

## Key findings

- The thermal decomposition risk of the four raw materials was classified as level 1.
- The process hazard level of nitration and quenching was evaluated as level 5.
- Risk mitigation strategies were proposed based on the comprehensive assessment.

## Abstract

This paper introduces the nitration process of obtaining the synthetic intermediate 1-(2-chloro-4-fluoro-5-nitrobenzene)-4-difluoromethyl-4,5-dihydro-3-methyl-1,2,4-triazol-5(1H)-one of pyraclostrobin using raw materials fluorobenzotriazolone, fuming nitric acid, fuming sulfuric acid, and toluene. The exothermic characteristics of the nitration, quenching, extraction, and alkali washing in the nitration reaction were studied, and the thermal decomposition risk of the raw materials and the secondary decomposition risk of the products in the nitration process were evaluated. The results showed that the thermal decomposition risk of the four raw materials was level 1. The acceptable level of runaway reaction in the nitration process was evaluated to be level 2, the acceptable level of runaway reaction in the quenching was level 3, the acceptable level of runaway reaction in the extraction and the alkali washing was level 1, the process hazard level of the nitration reaction and the quenching was evaluated to be level 5, and the process hazard level of the extraction and the alkali washing was level 1. Based on the comprehensive assessment results, targeted risk mitigation and control strategies are proposed to ensure process safety.