Continuous flow nitration of salicylic acid using HNO 3 /AcOH was studied in the SS316 tubular microreactor. At specific reaction conditions, complete conversion of the reactant was achieved in less than 7 min. It yielded only mononitro derivatives with a higher selectivity of 5-nitrosalicylic acid. Presence of the lower amount of acetic acid in the reaction mixture was seen to be detrimental, leading to precipitation of the desired product (5-nitrosalicylic acid). Reaction at higher temperatures yielded byproducts. The continuous mode operation using the system comprising the microdevices was demonstrated for 2 h with consistent composition at the outlet.

A continuous synthesis approach with multipoint dosing of one of the reagents is demonstrated for the synthesis of sulfoxide compounds such as proton pump inhibitors. Use of multipoint dosing of the oxidizing agent helped to minimize the possibility of over-oxidation leading to sulfone. Different oxidizing agents were used, and the effect of various parameters (viz. mole ratio of sulfide to oxidizing agent, temperature, residence time, concentration of oxidizing agent, etc.) on the yield of the desired sulfoxide compound was studied. Single-point and multipoint dosing approaches of the oxidizing agent were used for the most promising set of parameters. The performance was compared in terms of conversion of sulfide and the selectivity of the desired sulfoxide. Numbering up approach was used to produce the sulfoxide in a relatively large quantity at laboratory scale with complete conversion and over 99% selectivity for the sulfoxide.

A series of Mg3:Fex+Ce1-x LDHs (3:1) were synthesized by co-precipitation method by varying molar ratio of Fe:Ce between 1:0 to 0:1 (LDH-1 to LDH-6). All synthesized LDHs were characterized by XRD, FT-IR, TEM, N2 sorption, benzoic acid titration and XPS in detail and evaluated for selective synthesis of dimethyl carbonate by transesterification of ethylene carbonate with methanol. It was demonstrated that the structural and basic properties of synthesized LDHs were strongly dependent on the Fe:Ce molar ratio (Ce concentration). The correlation between their physicochemical properties and catalytic performance was studied in detail. Among all synthesized LDHs the best result was obtained with LDH-3 (Fe:Ce=0.85:0.15) where LDH structure remained intact, and showed high number of strong basic sites on LDH surface. LDH-3 was recycled 7 times while maintaining high catalyst activity and selectivity towards DMC. The obtained results elucidate the important role of Ce in modifying the basic properties of LDH in enhancing the catalytic activity for DMC synthesis.

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A series of binary mixed metal oxides (MMOs) were synthesized by combination of Mn+/Al3+ (Mn+= Li, Mg, Co, Ni, Zn) via co‐precipitation method and screened for transesterification of propylene carbonate (PC) with methanol. The aim of this study was to understand the role of acid‐base properties of MMOs on the activity and selectivity towards dimethyl carbonate (DMC) synthesis. The MMOs were characterized in detail by XRD, BET, TEM, NH3 and CO2‐TPD techniques. Catalysts synthesized by various combination of Mn+/Al3+ showed different textural and surface properties and the strength of acid‐base sites were also found to be significantly altered. These changes in physicochemical properties significantly affected the PC conversion and selectivity to DMC. Li+ incorporated in Al3+ showed the formation of octahedral α‐LiAlO2 phase having more amounts of active sites (O2−) present on the edges and corner of the structure. This resulted in easy accessibility of active sites and higher activity compared to other catalysts screened. Furthermore the catalyst retained high activity and selectivity for six consecutive recycle experiments; which is highly desirable for large‐scale application.