Objective

Nalas Engineering Services, Inc. (Nalas) aims to develop a scalable, affordable and environmentally sustainable process to manufacture the 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) precursor 1,3,5-trichlorobenzene (TCB) or its intermediate 1,3,5-trichloronitrobenzene (TCNB) for the Department of Defense and Department of Energy. The current manufacturing routes are plagued by harsh conditions, including use of chlorine gas, benzene, and high temperatures requiring large amounts of energy, etc. This limited scope effort will seek to determine the viability of the processes and products for use in manufacturing TATB with the long-term objective (outside of this scope) to establish a continental U.S. manufacturing capability for TCB (or TCNB) at Nalas. This effort will be responsive to the needs of reducing hazardous wastes in the production of Energetic Materials and Formulations under the Weapons Systems and Platforms area.

Technical Approach

Nalas plans to evaluate and develop environmentally-acceptable synthesis processes to: 1) chlorinate aniline to trichloroaniline (TCA) and, 2) convert TCA into the desired target products: TCB or TCNB. The chlorination of aniline has been known for at least 90 years.1 However, this chlorination, not unlike the direct chlorination of benzene, uses hydrochloric acid and chlorine gas or sulfuryl chloride, carrying many of the same environmental issues including chlorine and sulfur dioxide emissions. In 2009, Navy scientists at China Lake performed a brief study to evaluate other, more favorable chlorination methods to convert aniline to TCA as well as a method to deaminate the TCA to generate TCB.2 While not a part of this effort, it is worth mentioning that there are ongoing efforts by other organizations to produce aniline through biomanufacturing routes, which if successful in commercializing, will make this overall route to TCB (or TCNB) even more environmentally-friendly and less reliant on fossil fuels.

Nalas has in-house expertise and tools to execute this limited scope effort which will be greatly enabled through data-rich experimentation. Experiments may include use of in situ reaction monitoring tools (e.g. Fourier Transform Infrared spectroscopy, Raman) to ascertain reaction kinetics and heat flow calorimetry to understand thermodynamics. Collectively, the experimentation will allow the team to obtain greater understanding and knowledge of chemical processes with fewer experiments. These evaluations will enable Nalas to assess the viability of the various processes, with regards to safety, cost, environmental impact, and scalability. The team will down-select a few synthetic routes and make recommendations for further efforts aimed to advance their manufacturing readiness level.

Benefits

Successfully meeting the objective positions Nalas to become a domestic manufacturing source for the critical chemical, TCB (or TCNB). The long-term benefit is establishment of an environmentally acceptable manufacturing process and ultimately prevents “off-shoring” of the environmental issues. The short-term benefit is down-selection of promising synthetic routes that have high probability of transitioning to environmentally acceptable manufacturing processes for TCB and/or TCNB. 

1 Chattaway, F. D.; Irving, Harry (1933). 44. 2 : 4 : 6-Trichloroaniline. Journal of the Chemical Society (Resumed), 142–. doi:10.1039/jr9330000142 

2 Matthew C. Davis (2009): Chlorination of Aniline and Methyl Carbanilate by N-Chlorosuccinimide and Synthesis of 1,3,5-Trichlorobenzene, Synthetic Communications: An International Journal for Rapid Communication of Synthetic Organic Chemistry, 39:6, 1100-1108 

3 A) https://www.covestro.com/en/sustainability/flagship-solutions/white-biotechnology; B) Winter, B.; Meys, R.; Bardow, A. Journal of Cleaner Production 290 (2021) 125818. https://doi.org/10.1016/j.jclepro.2021.125818