Synthesis of CTA and DNAN Using Flow Chemistry

Mittal, Ankit; Prakash, Gaurav; Pathak, Pramod

doi:10.1002/ajoc.202200444

Cited by 7 publications

(7 citation statements)

References 27 publications

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“…Therefore, continuous flow hydrogenation has been developed to reduce the inherent drawbacks of batch reactor methods . Although continuous flow hydrogenation with immobilized metal catalysts has evolved considerably in recent years, most of the advantages of continuous flow are being used for organic liquid–liquid reactions, , while gas–liquid reactions have received much less attention, , despite the fact that 10% of the reactions in the fine chemical industry involve hydrogenation catalysis . One possible reason is that most of these reactions require heterogeneous catalysts, which involve the complex hydrodynamics of the gas–liquid–solid three-phase system. , …”

Section: Introductionmentioning

confidence: 99%

Heterogeneous Continuous Flow Hydrogenation of Hexafluoroacetone Trihydrate and Its Kinetic Modeling

Xue

et al. 2023

Ind. Eng. Chem. Res.

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Hexafluoroisopropanol (HFIP) is an important intermediate of sevoflurane, an inhalation anesthetic for pediatric anesthesia, and it is produced industrially mainly by the catalytic hydrogenation reduction of hexafluoroacetone (HFA). In previous studies, the hydrogenation of HFA was usually performed in batch reactors with the disadvantages of harsh reaction conditions and low conversion rates. On the other hand, continuous flow technology is increasingly being used for intrinsically safe hydrogenation processes to avoid safety issues caused by the accumulation of hydrogen gas in high-pressure reactors. In this study, a continuous flow system was developed in a micropackedbed reactor, and the intrinsic kinetics of the reaction were studied. This continuous flow process minimized mass and heat transfer problems and achieved higher productivity in terms of time and space yield than traditional process methods. Under kinetically controlled conditions, the operating conditions were varied with temperature between 363 and 393 K, hydrogen pressure of 10 bar, and catalyst loading between 0.1 and 0.5 g. In the end, we achieved conversion and selectivity of up to 99% and a space−time yield of about 9 times that of the batch reactor. To further investigate the long-term stability of the reaction system, the flow system was successfully operated for 90 h at a liquid flow rate of 0.5 mL/min. In addition, residence time distribution curves at different flow rates were determined, and possible mechanistic pathways of the reaction were explored based on the Langmuir−Hinshelwood method. The reaction was found to be an adsorption−desorption type with a mechanism of competitive adsorption by H 2 dissociation, and the thermodynamic properties associated with the rate constants were estimated.

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Section: Introductionmentioning

confidence: 99%

Heterogeneous Continuous Flow Hydrogenation of Hexafluoroacetone Trihydrate and Its Kinetic Modeling

Xue

et al. 2023

Ind. Eng. Chem. Res.

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“…[26] Microreactor allows the reaction to complete within a very short residence time which minimizes nitrate esters decomposition. [27] Microreactors contain a very low quantity of reaction mass at any point in time which minimizes the risk during accidents. [28] So, using flow chemistry approach, it is possible to design an inherently safer and economical process for nitration of polyols to produce nitrate esters.…”

Section: Introductionmentioning

confidence: 99%

“…In flow chemistry approach, microreactor provides a large surface to volume ratio which allows high rates of heat and mass transfer, and are capable of dissipating large heat generated in nitration reaction [26] . Microreactor allows the reaction to complete within a very short residence time which minimizes nitrate esters decomposition [27] . Microreactors contain a very low quantity of reaction mass at any point in time which minimizes the risk during accidents [28] .…”

Section: Introductionmentioning

confidence: 99%

Highly Scalable and Inherently Safer Preparation of Di, Tri and Tetra Nitrate Esters Using Continuous Flow Chemistry

Mittal,

Pathak,

Prakash

et al. 2023

Chemistry A European J

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Nitrate esters are important organic compounds having wide application in energetic materials, medicines and fuel additives. They are synthesized through nitration of aliphatic polyols. But the process safety challenges associated with nitration reaction makes the production process complicated and economically unviable. Herein, we have developed a continuous flow process wherein polyol and nitric acid are reacted in a microreactor to produce nitrate ester continuously. Our developed process is inherently safe and efficient. The process was optimized for industrially important nitrate esters containing two, three and four nitro groups. Molecules include glycol dinitrates: 1,2‐propylene glycol dinitrate (PGDN), ethylene glycol dinitrate (EGDN), diethylene glycol dinitrate (DEGDN), triethylene glycol dinitrate (TEGDN); trinitrates: trimethylolethane trinitrate (TMETN), 1,2,4‐butanetriol trinitrate (BTTN); tetranitrates: erythritol tetranitrate (ETN). The optimized process for each molecule provided yield > 90% in a short residence time of 1 min corresponding to a space time yield of > 18 g/h/mL of reactor volume.

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“…Sometimes such modifications become challenging. Recently, our group has reported flow chemistry approach to synthesize high energy compounds namely cyanuric triazide (CTA) and 2,4‐dinitroanisole (DNAN), at production rate of 30 g/hr in a lab scale microreactor [11] …”

Section: Introductionmentioning

confidence: 99%

“…Recently, our group has reported flow chemistry approach to synthesize high energy compounds namely cyanuric triazide (CTA) and 2,4-dinitroanisole (DNAN), at production rate of 30 g/hr in a lab scale microreactor. [11] Both TNAN and picramide, contains three nitro groups on one benzene ring, and are sensitive compounds. Methoxy group is prone to hydrolysis during nitration, resulting in formation of phenols.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Picramide Using Nitration and Ammonolysis in Continuous Flow

Mittal

Prakash

Pathak

2022

Chemistry An Asian Journal

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This paper describes a safer, scalable and continuous process for synthesis of picramide. The process consists of two steps: step-1. nitration of p-nitroanisole (PNAN) to 2,4,6-trinitrianisole (TNAN); step-2. ammonolysis of TNAN to picramide. Both the steps were optimized in flow, with yield of 90% and 98% in step-1 and step-2 respectively. Picramide with HPLC purity greater than 99% was obtained. When compared with batch, in step-1, flow process provided significant advantage in selectivity and yield. The optimized flow process was scaled to 25 g/hr production rate in a laboratory flow reactor. The method can be considered fit for the safe production of picramide at commercial scale.

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Synthesis of CTA and DNAN Using Flow Chemistry

Cited by 7 publications

References 27 publications

Heterogeneous Continuous Flow Hydrogenation of Hexafluoroacetone Trihydrate and Its Kinetic Modeling

Heterogeneous Continuous Flow Hydrogenation of Hexafluoroacetone Trihydrate and Its Kinetic Modeling

Highly Scalable and Inherently Safer Preparation of Di, Tri and Tetra Nitrate Esters Using Continuous Flow Chemistry

Synthesis of Picramide Using Nitration and Ammonolysis in Continuous Flow

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