Batch-type Reactor Research Articles

Pulsed Discharge Plasma over a Water Surface Induces Decoloration of Dyes

It was well known that plasma can be defined as a partially ionized gas composed of ions, electrons and neutral species. Recently, plasma-water interaction has attracted growing interest as it may provide experimental chemists with a quite unique reaction medium. In this work, decoloration of dyes in water as a reaction media and the effects of various parameters with pulsed high-voltage discharge plasma are studied. Such as plasma applied under hydrothermal conditions generates high-energy electrons, ions, and radicals, which in turn may generate new reaction fields, leading to effective organic compounds oxidation for both homogeneous and heterogeneous reactions. Here, we utilize pulse discharge plasma over water surface to study the decoloration of Orange G, Orange II, Congo Red, and Naphthol Blue Black. They were directly fed as starting materials without additives. The experiments were conducted under argon atmospheric at 313 K using a batch type reactor. The products were directly analyzed by UV-Vis (ultra violet-visible) spectrophotometer V-550. The decoloration rate increased with increasing peak pulse voltage and pulse numbers, presumably due to the increased electric field energy. Based on these results, the present system may be promising.

Nitrobenzene Hydrogenation on Au/TiO2 and Au/SiO2 Catalyst: Synthesis, Characterization and Catalytic Activity

Recently, gold has been proposed as an active phase for the hydrogenation of nitro-arenes. This metal has been rarely used in hydrogenation reactions because gold does not possess hydrogen chemisorption capacity. However, small gold particles behave differently and they may be able to chemisorb hydrogen to same extent, leading to possible activity in hydrogenation reactions. This may provide an advantage because the reactions catalyzed by highly dispersed gold particles may be better controlled. In this work, TiO2 and SiO2 supported Au catalysts were prepared by the deposition–precipitation method using urea and NaOH to precipitate the metallic component at different temperatures and hydrogen pressures. The metal loading for all the catalysts was 1 wt%. The catalysts were characterized by X-ray diffraction, high resolution transmission electron microscopy among others. The catalysts were then evaluated in the hydrogenation of nitrobenzene in a batch type reactor at 25 °C. All the catalysts were active in the hydrogenation reaction and the major obtained product was aniline.

Characteristics of waste printing paper and cardboard in a reactor pyrolyzed by preheated agents

We studied the characteristics of waste printing paper and cardboard particles in a reactor pyrolyzed by preheated agents with the aim of simulating a real case in a fixed-bed gasifier. A TGA/DSC was first used to study of the kinetics and enthalpy change of the printing paper and cardboard pyrolysis. Pyrolitic conversion was further carried out in a batch-type reactor with non-electrical heating. Syngas, tar and char were produced and characterized from printing paper and cardboard pyrolysis at 400°C, 500°C and 600°C. Different flow rates of carrier gas were applied to study the effect of residence time on the products distribution. When the flow rate increased, the relative mass change of gas agrees with that of tar. With increase in temperature, the yield of furfural, olefins and other non-aromatic compounds in tar decreased, while phenols and heavier aromatic hydrocarbons increased. The evolution of CO2, CO and other gas species in the syngas was presented. Van Krevelan diagram of chars was also presented in the paper.

Hydrogenation of substituted aromatic nitrobenzenes over 1% 1.0 wt.%Ir/ZrO2 catalyst: Effect of meta position and catalytic performance

This study is based on 1%Ir/ZrO2 catalyst which was studied in the hydrogenation of aromatic meta-substituted nitrobenzene in liquid phase. The catalyst was prepared by traditional impregnation method using IrCl3 and it has been characterized in terms of temperature-programmed reduction (TPR), ICP-MS, BET area, X-ray diffraction, HR-TEM and XPS measurements. The hydrogenation was evaluated in a batch type reactor at 298K using ethanol like a solvent. The catalyst showed the formation of zero valent and partially oxidized Iridium (Irδ+) is established post-TPR and XPS characterization. The metal particle size exhibited a wide distribution with mean size 1.8nm. Ir/ZrO2 was active in all the hydrogenation reactions with elevated conversion and promoted exclusive NO2 group reduction, resulting in the sole formation of the corresponding amino-compound except for CHO and CHCH2meta-substituted nitrobenzene. We associate this response to a reducible group competition between NO2 and CHO or CHCH2. Reactant activation on the catalyst generates a negatively charged intermediate, consistent with a nucleophilic mechanism. The presence of electron-donating substituents is shown to decrease NO2 reduction rate. This effect is quantified in terms of the Hammett relationship where a linear correlation between the substituent constant (σi) and rate is established and a reaction constant (ρ) 0.639. The data generated provide the first report of the catalytic action of supported Ir in the hydrogenation of meta-substituted nitroarenes and establish the nature of the hydrogenation en liquid phase.

A Degradation Kinetic Study on Pyrolysis of Three Biomass Samples and Co-pyrolysis of Hazelnut Shell and Ultra-high Molecular Weight Polyethylene Blends Using a Silver Indicator

A kinetic study was proposed in pyrolysis process supplementary to thermo-gravimetric analysis. Three different biomasses, hazelnut shell, olive residue, and tea waste, and hazelnut shell and ultra-high molecular weight polyethylene mixture were analyzed kinetically in a batch-type tubular pyrolysis reactor. Reaction times were measured with the changing color of silver indicator, which was attached to the terminal of pyrolysis set up at various specified temperatures between 623 and 923 K. The Arrhenius plots were obtained and the activation energies (Ea ) of reaction values were calculated from the slope of linear curves. For pure biomass, two linear degradation zones were detected possibly belonging to cellulose and hemicellulose. In the case of hazelnut shell and ultra-high molecular weight polyethylene mixtures, linearity of Arrhenius plots were grasped with the modification of the pre-exponential factor of the basic Arrhenius equation. This type of kinetic method directly involves the basic parameters, namely, reaction time and temperature for supplementation of kinetic analysis.

Enhancing operational stability and exhibition of enzyme activity by removing water in the immobilized lipase‐catalyzed production of erythorbyl laurate

Erythorbyl laurate was continuously synthesized by esterification in a packed-bed enzyme reactor with immobilized lipase from Candida antarctica. Response surface methodology based on a five-level three-factor central composite design was adopted to optimize conditions for the enzymatic esterification. The reaction variables, such as reaction temperature (10-70°C), substrate molar ratio ([lauric acid]/[erythorbic acid], 5-15), and residence time (8-40 min) were evaluated and their optimum conditions were found to be 56.2°C, 14.3, and 24.2 min, respectively. Under the optimum conditions, the molar conversion yield was 83.4%, which was not significantly different (P < 0.05) from the value predicted (84.4%). Especially, continuous water removal by adsorption on an ion-exchange resin in a packed-bed enzyme reactor improved operational stability, resulting in prolongation of half-life (2.02 times longer compared to the control without water-removal system). Furthermore, in the case of batch-type reactor, it exhibited significant increase in initial velocity of molar conversion from 1.58% to 2.04%/min.

Non Catalytic Transesterification of Vegetables Oil to Biodiesel in Sub-and Supercritical Methanol: A Kinetic’s Study

Non catalytic transesterification in sub and supercritical methanol have been used to produce biodiesel from palm oil and soybean oil. A kinetic study was done under reaction condition with temperature and time control. The experiments were carried out in a batch type reactor at reaction temperatures from 210 °C (subcritical condition) to 290 °C (the supercritical state) in the interval ranges of temperature of 20 °C and at various molar ratios of oil to methanol. The rate constants of the reaction were determined by employing a simple method, with the overall chemical reaction followed the pseudo-first–order reaction. Based on the results, the rate constants of vegetables oil were significantly influenced by reaction temperature, which were gradually increased at subcritical temperature, but sharply increased in the supercritical state. However, the rate constants of soybean oil were slightly higher than that of palm oil. The activation energy for transesterification of soybean oil was 89.32 and 79.05 kJ/mole for palm oil. Meanwhile, the frequency factor values of both oils were 72462892 and 391210 min-1, respectively. The rate reaction for both of oil were expressed as -rTG = 72462892 exp(-89.32/RT)CTG for soybean oil and -rTG = 391210 exp(-79.05/RT)CTG for palm oil. © 2013 BCREC UNDIP. All rights reserved Received: 18th October 2012; Revised: 14th December 2012; Accepted: 16th December 2012 [ How to Cite : N.P. Asri, S. Machmudah, W. Wahyudiono, S. Suprapto, K. Budikarjono, A. Roesyadi, M. Goto, (2013). Non Catalytic Transesterification of Vegetables Oil to Biodiesel in Sub-and Supercritical Methanol: A Kinetic’s Study. Bulletin of Chemical Reaction Engineering &amp; Catalysis , 7 (3): 215-223. (doi:10.9767/bcrec.7.3.4060.215-223)] [ Permalink/DOI : http://dx.doi.org/10.9767/bcrec.7.3.4060.215-223 ] View in |

ChemInform Abstract: A Study on the Role of Reaction Modeling in Multi‐Phase CFD‐Based Simulations of Chemical Looping Combustion

AbstractReview: 54 refs.

Degradation of brominated epoxy resin and metal recovery from waste printed circuit boards through batch sub/supercritical water treatments

Waste printed circuit boards (WPCBs) contain high amount of brominated flame retardants and heavy metals which may bring a series of environmental and health problems. In the present study, an effective and benign process using sub- and supercritical water (sub/SCW) to simultaneously degrade brominated epoxy resin and recover metals from WPCBs was developed. Experiments were performed in a batch-type reactor with temperatures ranging from 200 to 400°C, water adding amounts from 10 to 40ml and holding times from 30 to 240min. The results showed that brominated epoxy resins (BERs) could be quickly and efficiently decomposed under sub/SCW condition. The debromination rate was 97.8% by controlling the temperature, water adding amount and holding time at 400°C, 40ml and 120min, respectively. Most of the bromine was changed into HBr and around 97.7% was enriched in water. Meanwhile, bromine-free oil was obtained of which the main compositions were phenol (58.5%) and 4-(1-methylethyl)-phenol (21.7%). After the sub/SCW treatments, the glass fibers and copper foils in the residue can be easily liberated and recovered respectively. The copper recovery rate reached 98.11% in the purities of 96.74% (grain size >2.0mm) and 92.74% (0.147–2.0mm). This study provides an efficient and green approach for WPCBs recycling.

Production of 5-hydroxymethyl Furfural from Sugarcane Bagasse under Hot Compressed Water

5-hydroxymethyl furfural (5-HMF) is an important organic compound for production of renewable plastics, fine chemicals and fuel. Nowadays, the manufacturing of 5-HMF is mainly derived from edible glucose and fructose. In order to replace the use of food crops such as glucose and fructose as a feed stock, experiment were conducted by using sugarcane bagasse as a raw material. These experiments were performed in a batch-type reactor containing slurry of 10ml of water and 1.2g of solids. Effect of temperature (200°C and 300°C) and reaction times (3 to 30min) on 5-HMF yield was studied. The highest yield of 5-HMF was found at 270°C (10min). Moreover, at temperature (>300°C) and long reaction time, 5-HMF production yield decreased, this is mainly because of the heightened decomposition and polymerization of 5-HMF to formic acid and char,respectively. This study reveal that, condition for production of 5-HMF achieved at medium range of temperature and reaction time.

Clean synthesis of acetaldehyde oxime through ammoximation on titanosilicate catalysts

Acetaldehyde oxime has been synthesized though the liquid-phase ammoximation of acetaldehyde with ammonia and hydrogen peroxide over various titanosilicate catalysts. Titanium mordenite (Ti-MOR), prepared from highly dealuminated mordenite and TiCl4 vapor by a secondary synthesis method, was superior to TS-1 and Ti-MWW catalysts both in aldehyde conversion and in oxime selectivity. The reaction parameters were investigated systematically in a batch-type reactor for Ti-MOR, such as solvent effect, temperature, time, catalyst loading, amounts of ammonia and hydrogen peroxide relative to aldehyde as well as addition methods of the reactants. Under optimized conditions, Ti-MOR was capable of showing an aldehyde conversion of 99% and an oxime selectivity of 97%. In comparison with TS-1 and Ti-MWW, the advantage of Ti-MOR in acetaldehyde ammoximation was mainly attributed to its lower ability for oxidation to convert the aldehyde to acetic acid. There was almost no effect resulting from the addition mode of the reactants; Ti-MOR with its special characteristics was unique in catalytic behavior and easy handling. An overview of the reaction routes involved in acetaldehyde ammoximation has been provided.

PEMBUATAN BAHAN BAKU SPREADS KAYA KAROTEN DARI MINYAK SAWIT MERAH MELALUI INTERESTERIFIKASI ENZIMATIK MENGGUNAKAN REAKTOR BATCH

Enzymatic interesterification of red palm oil (a mixture of red palm olein/RPO and red palm stearin/RPS in 1:1 weight ratio) and coconut oil (CNO) blends of varying proportions using a non-specific immobilized Candida antartica lipase (Novozyme 435) was studied for the preparation of spread stock. The interesterification reaction was held in a batch-type reactor. Two substrate blends were chosen for the production of spread stock i.e. 77.5:22,5 and 82.5:17.5 (RPO/RPS:CNO, by weight) through enzymatic interesterification in three different reaction times (2, 4, and 6 hours). The interesterification reactions were conducted at 60°C, 200 rpm agitation speed and 10% of Novozyme 435. The interesterified products were evaluated for their physical characteristics (slip melting point or SMP and solid fat content or SFC) and chemical characteristics (carotene retention, moisture content, and free fatty acid/FFA content). All of the interesterified products had lower SFC and SMP as compared to the initial blends. The SMP and SFC increased in longer reaction times. The SMP ranged from 30.8°C to 34.9°C. The carotene retention ranged from 74.80% to 81.08%, while the moisture content and FFA content increased in longer reaction times. The interesterified products had desirable physical properties for possible use as a spread stock rich in carotene.

Microcapsule with a heterogeneous catalyst for the methanolysis of rapeseed oil

This study has demonstrated that microcapsules can be used as a microreactor for the transesterification of rapeseed oil with calcium oxide (CaO) base catalyst. CaO-loaded microcapsules were prepared by coextrusion technique, and the transesterification reaction was carried out by adding methanol into the prepared microcapsules and oil in a batch-type reactor. Results showed that the microcapsules system could promote the transesterification and hinder the dissolution of the catalyst, in contrast to a biodiesel production with CaO particles. The optimal conditions for methanol to oil molar ratio, catalyst content in the microcapsules and reaction temperature were found to be 8:1, 20wt.%, and 65°C, respectively. The results of reusability tests showed that CaO-loaded microcapsules could be successfully reused for three times without loss of the catalytic activity. It was concluded from these results that microcapsules have the potential to improve the performance of solid base catalyst for biodiesel production.

Effects of water in water/phenol mixtures on liquefaction of Japanese beech as treated under subcritical conditions

Abstract Japanese beech (Fagus crenata) has been liquefied by water-added subcritical phenol without a catalyst in a batch-type reaction vessel. The effect of water/phenol ratio was studied under conditions of various treatment times. The fractions soluble in phenol/water as well as the insoluble residues were characterized. Liquefaction kinetics was investigated assuming the validity of the first-order reaction rate law. The degree of phenolation was increased with increasing treatment times and water content in phenol/water solvent. Treatment at 270°C under 3.1 MPa pressure for 10 min with a water/phenol ratio of 25:75 gave the best liquefaction result. Various oligosaccharides derived from cellulose and hemicelluloses were found to be hydrolyzed and solubilized in the water-soluble portion.

Removal of As(V) from aqueous solutions by iron coated rice husk

A lignocellulosic material extracted from rice husk (Oryza sativa), Vietnam, was modified as a new adsorbent for the removal of As(V) ions from aqueous solution. Iron was coated onto this adsorbent by hydrolization of ferric nitrate while adding an alkaline solution drop wise into the batch type reactor. The adsorption of As(V) ions from aqueous solution on coated rice husk was then studied at varying pH, As(V) concentrations, contact times, ionic strength, and adsorbent amounts. The minimum contact time to reach equilibrium is about 6h. The adsorption of As(V) anions on the coated rice husk was found to be highly pH dependent due to Coulomb interactions between As(V) species in solution and positively charged surface groups RH-FeOOH, as well as formation of chelate complexes with naturally occurring carboxyl and carbonyl functional groups in the matrix. As(V) adsorption on Fe(III)-coated rice husk (RH-FeOOH) from aqueous solution was studied in the pH range 2–10. The main effects of pH on adsorption are estimated by considering both the behavior of As(V) ions (hydrolysis and hydroxide precipitation) and the effect of pH on coordination. A strong effect of pH was demonstrated at pH 4.0 with a maximum percentage for removal of As(V) ions 94%. Although both Langmuir and Freundlich isotherms have been used to characterize the adsorption of As(V), the Langmuir model fitted the equilibrium data better than Freundlich model and confirmed the surface homogeneity of adsorbent. The maximum adsorption capacity is determined as 2.5mg/g of adsorbent at pH 4.0 for the Fe(III)-coated rice husk. It is concluded that initial As(V) concentration has an effect on the removal efficiency of RH-FeOOH. Higher adsorption of As(V) was observed at lower initial concentrations. RH-FeOOH as a low cost material is effective for the removal of As(V) ions and may become a valuable adsorbent to improve the ground water quality in Vietnam.

Partial hydrogenation of polyunsaturated fatty acid methyl esters over Pd/activated carbon: Effect of type of reactor

Partial hydrogenation of polyunsaturated FAMEs has been investigated on a Pd/C catalyst. The effect of type of reactor: batch and continuous flow reactors, on the FAME composition and properties of a biodiesel product were studied. In addition, many characterization techniques such as XRD, BET, FE-SEM, and CO-chemisorption were used to examine the prepared catalysts. The result showed that the partial hydrogenation of polyunsaturated FAMEs in a batch-type reactor provides higher selectivity towards C18:1 than that of a continuous-flow reactor. However, at the low conversion (78%); selectivity of C18:1 obtained from both types of reactors were almost the same.

Pyrrole conversion induced pulse discharge plasma over a water surface under high-pressure argon

Electric field generated by pulsed high-voltage discharge plasma over water surface has been performed under high-pressure argon environments to oligomerize pyrrole compound. In this preliminary study, oligomerization of pyrrole in water as a reaction media and the effects of various parameters with pulsed high-voltage arc discharge plasma are studied. Such as plasma applied under hydrothermal conditions generates high-energy electrons, ions, and radicals, which in turn may generate new reaction fields, leading to effective organic compounds oxidation for both homogeneous and heterogeneous reactions. Here, we utilize pulse discharge plasma over water surface to study the removal characteristics for pyrrole into more valuable higher amines group which has been fascinating for both the industry and the scientific community. The experiments were conducted at 313K and 1–2MPa using a batch type reactor. Intermediate compounds from the conversion of pyrrole in the aqueous products were identified by UV–vis (ultra violet–visible) spectrophotometer and quantified using high performance liquid chromatography (HPLC). The maximum pyrrole conversion was 24.40% with a discharge plasma pressure of 2MPa with 10,000×. It was found that pyrrole conversion can be raised considerably by increasing reaction pressure and discharge plasma amount.

Coke Formation during Thermal Decomposition of Methylcyclohexane by Alkyl Substituted C5 Ring Hydrocarbons under Supercritical Conditions

In this study, a mechanism for coke formation of methylcyclohexane (MCH) was investigated by sampling products in a batch type reactor during thermal decomposition. Alkyl substituted C5 ring hydrocarbons, which have a 5-member ring structure with alkyl groups as side chains, were the major products of thermal decomposition of MCH before coke formation (below 465 °C). The composition of alkyl substituted C5 ring hydrocarbons gradually increased without any decrease during the reactions before coke formation. The composition of alkyl substituted C5 ring hydrocarbons decreased after considerable increase, when coke formation occurred as 0.084 g coke/ml MCH for 10 h at 465 °C. Coke was formed via an increase in polycyclic aromatic hydrocarbons (PAHs). Based on this result, it was hypothesized that the abundance of alkyl substituted C5 ring hydrocarbons caused the formation of PAHs and coke. To identify the role of alkyl substituted C5 ring hydrocarbons on coke formation, thermal decomposition of MCH with 1,2,...

A kinetic study of esterification of naphthenic acids from a Colombian Heavy Crude Oil

This article presents the kinetic study of the esterification reaction of naphthenic acids from a Colombian heavy crude oil, with a Total Acid Number (TAN) of 7,33 mgKOH/g, in a batch type reactor. Temperature was changed between 150 - 250°C while the ratio moles of methanol per mole of carboxylic groups, remained constant in 20:1. The reaction time was varied from 0 - 600 minutes. Reduction in the concentration of naphthenic acids in the reactor is determined by the measurement of Number Total Acid (TAN), ASTM D 664. Naphthenic acids were extracted from the crude and structurally characterized by Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR) and Gel Permeation Chromatography (GPC).&#x0D; The esterified oil was analyzed by FTIR, to identify the variation of the main functional groups. After determining the activation energy, frequency factor and, reaction order, a kinetic law was proposed for the esterification of naphthenic acids in Colombian heavy oil. Finally, it was evaluated the effect of esterification of naphthenic acids on the corrosion of steel ASTM A106 Gr.B. The corrosion of steel was reduced from 34,16 to 3,08 mils per year, (mpy), after esterification of naphthenic acids.

Depolymerization of poly(trimethylene terephthalate) in hot compressed water at 240–320 °C

Poly(trimethylene terephthalate) (PTT) was depolymerized in hot compressed water (HCW) using a fused-silica capillary reactor (FSCR) and a batch-type autoclave reactor. The phase behavior of PTT in water during the heating, reaction, and cooling processes was observed in an FSCR with a microscope and recorded by a digital camera. It was found that PTT can dissolve in water in a temperature range of 240–320 °C and form a homogeneous aqueous solution. The effects of the reaction temperature (240–320 °C) and reaction time (5–60 min) were evaluated in a batch-type autoclave reactor. The main depolymerization products of PTT were terephthalic acid (TPA) and 1,3-propanediol (1,3-PDO), which were identified by liquid chromatography mass spectrometry, Fourier-transform infrared spectroscopy, gas chromatography mass spectrometry, Raman spectroscopy, and quantified by high-performance liquid chromatography as well as gas chromatography. Additionally, it was found that 1,3-PDO was converted to 1,5-dioxocane partly in the presence of TPA. Under optimal reaction conditions, i.e. 300 °C, 15 min, with a water/PTT ratio of 8:1 (w/w), complete depolymerization was achieved, and the yields of TPA and 1,3-PDO reached 90.5% and 69.03%, respectively. Based on the results, a reaction mechanism for PTT depolymerization in HCW was proposed.