scholarly journals Modeling of Bimolecular Nitroxide Mediated Radical Polymerization of Styrene in Batch Reactor and Steady State Analysis of CSTR Reactor

2021 ◽  
Author(s):  
Basma Matti
Keyword(s):  
Steady State ◽  
Kinetic Model ◽  
Radical Polymerization ◽  
Batch Reactor ◽  
Polymeric Materials ◽  
Reaction Scheme ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Side Reactions ◽  
Feed Stream

Controlled radical polymerization (CRP) is a rapidly developing area in polymer science. Its versatility and ability to produce novel polymer structures are the main reasons which attract both academic and industrial interests. In particular, Nitroxide mediated Radical Polymerization (NMRP) is currently one of the three popular approaches in CRP. Polymeric materials synthesized by NMRP can be utilized for coatings, adhesives, lubricants, gels, thermoplastic and also for biomedical applications. Open literature shows an academic controversy over the kinetic mechanisms of NMRP and also over the kinetic reaction rate parameters. In this study, a kinetic mechanism describing the bimolecular NMRP was thoroughly discussed, reviewed and improved. In fact, two side reactions have been added to the most updated NMRP reaction scheme. Therefore, a kinetic model for a NMRP polymer reactor operating in batch and CSTR modes was developed based on a detailed reaction mechanism for thermal polymerization of styrene and also for bimolecular NMRP of styrene using benzoyl peroxide (BPO) as initiator and 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) as a radical controller. The kinetic model, consisting of a set of ordinary differential equations, was numerically integrated and validated with a set of experimental data obtained at temperature 120°C and [TEMPO]/[BPO] molar ratio 1.1. This model validation was done by means of a parameter estimation scheme to determine the "best" kinetic parameters. The model predictions were compared with data at 120 and 130°C for [TEMPO]/[BPO] molar ratios of 0.9, 1.1, 1.2, and 1.3. A good to very good agreement was obtained between the prediction and data. The non-linear behavior of the CSTR polymerization reactor was also analyzed using Matlab continuation program Matcont package. Typical hysteresis behavior, input and output multiplicities, as well as disjoint bifurcations were determined for this reactor. The bifurcation parameters selected are the coolant flow rate, feed stream temperature, residence time, initiator feed stream concentration and controller feed stream concentration. Bifurcation analyses reveal the stable and unstable operating regions of the reaction. Thus, the results obtained can be employed as a guide to develop a process control strategy for a better and safer operation of the NMRP polymerization reactors. Finally, a steady state optimization for the CSTR reactor was carried out in order to identify the optimal operating conditions of the NMRP process.

scholarly journals Modeling of Bimolecular Nitroxide Mediated Radical Polymerization of Styrene in Batch Reactor and Steady State Analysis of CSTR Reactor

2021 ◽  
Author(s):  
Basma Matti
Keyword(s):  
Steady State ◽  
Kinetic Model ◽  
Radical Polymerization ◽  
Batch Reactor ◽  
Polymeric Materials ◽  
Reaction Scheme ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Side Reactions ◽  
Feed Stream

Controlled radical polymerization (CRP) is a rapidly developing area in polymer science. Its versatility and ability to produce novel polymer structures are the main reasons which attract both academic and industrial interests. In particular, Nitroxide mediated Radical Polymerization (NMRP) is currently one of the three popular approaches in CRP. Polymeric materials synthesized by NMRP can be utilized for coatings, adhesives, lubricants, gels, thermoplastic and also for biomedical applications. Open literature shows an academic controversy over the kinetic mechanisms of NMRP and also over the kinetic reaction rate parameters. In this study, a kinetic mechanism describing the bimolecular NMRP was thoroughly discussed, reviewed and improved. In fact, two side reactions have been added to the most updated NMRP reaction scheme. Therefore, a kinetic model for a NMRP polymer reactor operating in batch and CSTR modes was developed based on a detailed reaction mechanism for thermal polymerization of styrene and also for bimolecular NMRP of styrene using benzoyl peroxide (BPO) as initiator and 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) as a radical controller. The kinetic model, consisting of a set of ordinary differential equations, was numerically integrated and validated with a set of experimental data obtained at temperature 120°C and [TEMPO]/[BPO] molar ratio 1.1. This model validation was done by means of a parameter estimation scheme to determine the "best" kinetic parameters. The model predictions were compared with data at 120 and 130°C for [TEMPO]/[BPO] molar ratios of 0.9, 1.1, 1.2, and 1.3. A good to very good agreement was obtained between the prediction and data. The non-linear behavior of the CSTR polymerization reactor was also analyzed using Matlab continuation program Matcont package. Typical hysteresis behavior, input and output multiplicities, as well as disjoint bifurcations were determined for this reactor. The bifurcation parameters selected are the coolant flow rate, feed stream temperature, residence time, initiator feed stream concentration and controller feed stream concentration. Bifurcation analyses reveal the stable and unstable operating regions of the reaction. Thus, the results obtained can be employed as a guide to develop a process control strategy for a better and safer operation of the NMRP polymerization reactors. Finally, a steady state optimization for the CSTR reactor was carried out in order to identify the optimal operating conditions of the NMRP process.

Value-Added Processing of Lactose: Preparation of Bioactive Lactobionic Acid Using a Novel Catalytic Method

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Khaled Belkacemi ◽  
Mirela Cristea Vlad ◽  
Safia Hamoudi ◽  
Joseph Arul
Keyword(s):  
Active Sites ◽  
Bimetallic Catalyst ◽  
Batch Reactor ◽  
Reaction Medium ◽  
Value Added ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Catalytic Method ◽  
Metals Loading ◽  
Ph Range

The microaerial oxidation of an aqueous solution of lactose to lactonionic acid (LBA) over the heterogeneous bimetallic catalyst Bi-Pd supported on mesoporous SBA-15 material was carried out in an agitated semi-batch reactor in alkaline medium within the pH range of 7 to 9.The present work focused on the synthesis and characterization of the bimetallic catalyst as well as optimization of the reaction operating conditions. To this purpose, the effect of both active metals loading on the support, metal/lactose ratio, reaction pH and dissolved oxygen concentration on the oxidation performances was examined at a very mild temperature of 65 oC.The bimetallic catalyst 1.02%Pd, 0.64%Bi/SBA-15, (Bi/Pd molar ratio of 0.3) showed the highest activity (96 % lactose conversion) and 100 % selectivity towards the targeted LBA product. Furthermore, the formulated catalyst proved to be stable in the reaction medium as both metals leaching was insignificant. Based on XRD and XPS analyses, it is suggested that the metals constituting the bimetallic catalyst active sites assemble into an intermetallic alloy having Bi1.75Pd stoichiometry.

scholarly journals Influence of NaCl on the polymerization of vinyl monomers by the suspension process

2019 ◽  
pp. 19-23
Author(s):  
Erika Montero ◽  
David Contreras-López ◽  
Rosalba Fuentes ◽  
María Del Rosario Galindo
Keyword(s):  
Batch Reactor ◽  
Research Work ◽  
Chemical Properties ◽  
Polymeric Materials ◽  
Operating Conditions ◽  
Suspension Process ◽  
Different Types ◽  
Physical And Chemical ◽  
And Chemical Properties

The production of artificial polymers is, today, one of themost important activities of the chemical industry, polymersare widely used in everyday life, as, there are different types of polymers, they can be used for different uses. These polymeric materials have unique mechanical, physical and chemical properties, which most other materials do not possess, not to mention that its cost is lower than the other materials. The present research work focuses on the determination of optimal operating conditions for the polymerization of styrene and methyl methacrylate in a Batch reactor, as well as the influence of inorganic salt in this case NaCl in the performance of reaction and in the size of the material polymer, through the process of suspension using a synthetic route of polymerization by radical free conventional (FRP), where viscometry to the polymeric material testing was performed for this way characterize it, and to determine factors of interest such as the molecular weight, etc.

scholarly journals Sintesis biodiesel rute non-alkohol menggunakan Candida rugosa lipase dalam bentuk tersuspensi

2018 ◽  
Vol 8 (2) ◽  
pp. 38
Author(s):  
Heri Hermansyah ◽  
Septian Marno ◽  
Rita Arbianti ◽  
Tania Surya Utami ◽  
Anandho Wijanarko
Keyword(s):  
Palm Oil ◽  
Kinetic Data ◽  
Methyl Acetate ◽  
Batch Reactor ◽  
Candida Rugosa ◽  
Candida Rugosa Lipase ◽  
Molar Ratio ◽  
Side Reactions ◽  
Biodiesel Synthesis ◽  
Suspended Form

Non-alcoholic route biodiesel synthesis using suspended Candida rugosa lipaseBiodiesel synthesis using biocatalyst can improve the disadvantage of alkali catalyst. Biocatalysts are not homogeneously mixed, so its separation is easy and it is also able to direct the reaction specifically without any unwanted side reactions. However, the application of biocatalysts in alcoholic environment degrades the biocatalyst quickly, and its stability suffers. To solve this problem, this research proposes to perform biodiesel synthesis through a non-alcohol route so that the activity and stability of the biocatalyst can be preserved. The biocatalyst used was Candida rugosa lipase in suspended form. Methyl acetate which served as alkyl group source was reacted with triglycerides from palm oil. The reaction was performed in a batch reactor, and HPLC was used to analyze reactants and product concentrations. Research results indicated that more than 86% of fatty acid chains from the palm oil triglycerides were converted to biodiesel at a biocatalyst concentration of 4 %-wt of the substrate, oil:alkyl molar ratio of 1:12, and reaction period of 50 hours. Furthermore, the kinetic data obtained using suspended enzyme, were also shown by concentration profile of tri-, di-, monoglycerides and biodiesel versus time in 50 hours reaction time.Keywords: biodiesel synthesis, interesterification, Candida rugosa lipase, non-alcohol route, triglycerideAbstrakSintesis biodiesel menggunakan biokatalis mampu memperbaiki kelemahan katalis alkali, yaitu tidak bercampur homogen, sehingga pemisahannya mudah dan mampu mengarahkan reaksi secara spesifik tanpa adanya reaksi samping yang tidak diinginkan. Namun penggunaan biokatalis di lingkungan beralkohol menyebabkan biokatalis terdeaktivasi secara cepat dan stabilitasnya menjadi buruk. Untuk menyelesaikan masalah tersebut, dalam riset ini diusulkan melakukan sintesis biodiesel melalui rute non-alkohol agar aktivitas dan stabilitas biokatalis tetap tinggi. Biokatalis yang digunakan adalah Candida rugosa lipase dalam bentuk tersuspensi. Metil asetat sebagai pensuplai gugus alkil direaksikan dengan trigliserida dari minyak kelapa sawit.  Reaksi dilakukan dalam reaktor batch dan HPLC digunakan untuk menganalisa reaktan dan produk. Hasil penelitian menunjukkan bahwa lebih dari 86% rantai asam lemak dari trigliserida minyak kelapa sawit berhasil di konversikan menjadi biodiesel pada kondisi konsentrasi biokatalis sebesar 4 %-wt substrat, rasio mol minyak:alkil sebesar 1:12 selama 50 jam reaksi. Selanjutnya, data kinetika menggunakan enzim tersuspensi juga ditunjukkan melalui profil konsentrasi tri-, di-, mono, dan biodiesel  terhadap waktu  selama 50 jam.Kata Kunci: sintesis biodiesel, interesterifikasi, Candida rugosa lipase, rute non-alkohol, trigliserida

scholarly journals Reactors functional parameters for sodium benzoate production: A comparative study

2019 ◽  
Author(s):  
Chem Int ◽  
Chukwuemeka Peter Ukpaka
Keyword(s):  
Benzoic Acid ◽  
Sodium Hydroxide ◽  
Sodium Benzoate ◽  
Flow Reactor ◽  
Batch Reactor ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Feed Ratio ◽  
Continuous Stirred Tank Reactor ◽  
Functional Parameters

The various process performances of the Batch Reactor, Continuous Stirred-Tank Reactor (CSTR) and Plug Flow Reactor (PFR) for the production of sodium benzoate from the reaction of sodium hydroxide and benzoic acid were investigated. The performance equations for the operation of Batch reactor, CSTR and PFR were developed for the analysis of the reactor’s functional dimensions and parameters. The analysis of the reactor’s functional parameters was performed at molar ratio of benzoic acid to sodium hydroxide of 1.5 to 3.0 at intervals of 0.5 and at the same reactor operating conditions. The set of reactors’ performance equations were solved simultaneously and then, simulated with the aid of MATLAB R2015a computer program. However, in terms of comparison at the same operating conditions, the size of the batch reactor was greater than that of CSTR which in turn was greater than that of the PFR, while the reverse was the case for heat generated per reactor volume. Also, the space time for CSTR was greater than that of the PFR while the space velocity for PFR was greater than that of CSTR. Following the results obtained from the analysis, the production of sodium benzoate from sodium hydroxide and benzoic acid can be executed in either of batch reactor, CSTR or PFR depending on the capacity of production and conditions of operation and the optimum performance was observed at molar feed ratio of 3.0.

scholarly journals Thermo-catalytic pyrolysis of polystyrene in batch and semi-batch reactors: A comparative study

2020 ◽  
pp. 0734242X2093674
Author(s):  
Amer Inayat ◽  
Katerina Klemencova ◽  
Barbora Grycova ◽  
Barbora Sokolova ◽  
Pavel Lestinsky
Keyword(s):  
Catalytic Pyrolysis ◽  
Enhanced Recovery ◽  
Batch Reactor ◽  
Polymeric Materials ◽  
Product Distribution ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Chemical Recycling ◽  
Batch Reactors ◽  
Reactor Type

Thermo-catalytic pyrolysis is considered as a promising process for the chemical recycling of waste polymeric materials aiming at converting them into their original monomers or other valuable chemicals. In this regard, process parameters and reactor type can play important roles for an enhanced recovery of the desired products. Polystyrene (PS) wastes are excellent feedstocks for the chemical recycling owing to the capability of PS to be fully recycled. In this respect, the present work deals with the thermo-catalytic pyrolysis of PS in batch and semi-batch reactor setups. The main goal was to perform a comprehensive study on the depolymerisation of PS, thereby investigating the effect of reactor type, catalyst arrangement, feed to catalyst ratio and residence time on the yields of oil and styrene monomer (SM). A further goal was to identify the optimum operating conditions as well as reactor type for an enhanced recovery of oil and SM. It was demonstrated that the semi-batch reactor outperformed the batch reactor in terms of oil and SM yields in both thermal (non-catalytic) and catalytic tests performed at 400°C. Furthermore, it was shown that the layered arrangement of catalyst (catalyst separated from PS) produced a higher amount of oil with higher selectivity for SM as compared to the mixed arrangement (catalyst mixed with PS). Moreover, the effect of carrier gas flowrate on the product distribution was presented.

scholarly journals A Comprehensive Kinetic Model of Fischer-Tropsch Synthesis over Supported Cobalt Catalyst

2017 ◽  
Author(s):  
Reza Jalilzadeh ◽  
Mahmoud Moqadam
Keyword(s):  
Kinetic Model ◽  
Fixed Bed ◽  
Operating Conditions ◽  
Tropsch Synthesis ◽  
Fixed Bed Reactor ◽  
Molar Ratio ◽  
Rate Equations ◽  
Type Model ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis

A comprehensive kinetic model of the Fischer-Tropsch synthesis (FTS) is developed in a fixed bed reactor under operating conditions (temperature, 230–235°C, pressure, 20–25 bar, gas hourly space velocity, 4000–5000 cm3(STP)/h/gcatalyst ,H2/CO feed molar ratio, 2.1) over a Co based catalyst. Reaction rate equations based on Eley-Rideal (ER) type model for initiation step and Langmuir-Hinshelwood-Hougen-Watson (LHHW) type model for propagation and termination steps of the FTS reactions have been considered and the readsorption of olefins were taken into account. The model that was reported in the literature was modified in order to explain many significant deviations from the ASF distribution. Optimum parameters have been obtained by Genetic Algorithms (GA). The calculated activation energies to produce n-paraffins and 1-olefins were in the range of 82.24 to 90.68 kJ/mol and 100.66 to 105.24 kJ/mol, respectively. The hydrocarbon distribution in FTS reactions was satisfactorily predicted particularly for paraffins.

Sign in / Sign up

Export Citation Format

Share Document