Modeling G-L-L-S Reactor: A Case of Hydrogenation of Nitrobenzene

Abstract

Gas–liquid–liquid–solid (GLLS) reaction systems are often encountered in manufacturing of fine and specialty chemicals. More often than not, such reaction systems involve multiple reactions, and selectivity toward the desired component always poses challenges. An adequate understanding of various parameters affecting GLLS reactor performance is essential to develop strategies for realizing desired selectivity. In this work, a comprehensive reaction engineering model for simulating four phase hydrogenation reactions has been developed. A generalized mixing cell based framework for a reaction system with four interacting phases (gas [G], aqueous [L], organic [L], and solid catalyst [S]) was developed. The model is written in a general way so as to specify one of the liquid phases as a continuous phase, and the other three phases are dispersed into it. In each cell, vapor space is included. The model includes the possibility of evaporation of solvent and internal condensation (in vapor space). The model can also be applied for a dead end (from a perspective of reacting gas) reactor. Model equations were solved using MATLAB. The equations and solution methodology were verified by comparing numerical solutions with available solutions of various limiting cases. A case of four phase hydrogenation of nitrobenzene to para amino phenol and aniline was considered to illustrate the application of the developed model. Key findings from the model were validated by comparing with laboratory scale experimental data. The model was then used to develop insights and guidelines for enhancing selectivity toward desired product. The developed model and presented results will be useful to develop general guidelines for design and optimization of GLLS reactors.

Gradient crystallinity and its influence on the poly(vinylidene fluoride)/poly(methyl methacrylate) membrane‐derived by immersion precipitation method

“…The disruption of the PVDF crystalline domain has been observed in the case of 60/40 membrane was due to the occupancy of amorphous PMMA at the interlamellar and interspherulitic regions of the PVDF and thereby preventing further lamellar growth of the semicrystalline polymer. 54 Inability to crystallize the PVDF polymer in 60/40 blend corroborated with the calorimetry study in which a diffused crystallization peak formed. The amorphous miscibility of the PMMA with PVDF hinders the formation of crystalline domains in the PVDF.…”

“…Reduction in the permeate flux was the indication pores compaction during the continuous flux experiment. 54 Shen et al studied the BSA separation of the PVDF membrane in presence of a hydrophilic grafting agent such as hydroxyl ethyl acrylate. 95 The grafted membrane shows higher BSA flux than the pure water flux due to the electrical double layer compression.…”

Study of the Electronic Structure of NiGa2S4 and Extraction of the Spin Hamiltonian Parameters from Ab Initio Calculations

“…Moreover, the natures of the ferroand antiferromagnetic couplings for J 1 and J 3 , respectively, generate spin frustrations. An interesting perspective would be to study the thermodynamic properties of this material with this model Hamiltonian and the powerful matrix product states method [88][89][90] to introduce collective effects.…”

Kinetics of cinnamaldehyde hydrogenation in four phase system

“…The approach presented in this work will be helpful for understanding kinetics of similar four phase hydrogenation systems. The intrinsic kinetics determined will be incorporated with mixing models for evaluating performance of multiphase flow reactors [36].…”