Korean Journal of Chemical Engineering (v.31, #3)

A simple, regioselective, environmentally clean and economical method for the preparation of side chain/ ring brominated aromatic compounds is reported in 70–98% yield by an electrochemical method using two phase electrolysis technique. Electrochemical reactions were carried out using aqueous 25–50 wt% sodium bromide containing catalytic amount (5 wt%) of hydrobromic acid as an aqueous phase and chloroform containing alkyl aromatic compounds as an organic phase, at a temperature of 0–30 °C in an undivided cell. The same two-phase electrolytic system can be used for the oxidation of benzylic alcohols to the corresponding benzaldehydes in 80–94% yield without over oxidation to carboxylic acids. The advantage of this very mild procedure is a room temperature reaction used with an undivided cell. Excellent conversions are observed. After completion of alcohol oxidation the electrolyte can be reused for a number of times, demonstrating “spent reagent” free electro organic reaction as an attractive one. In the case of side chain/ring bromination of alkyl aromatic compounds, the electrolyte can be reused after making up the concentration of the electrolyte with 47 wt% HBr solution. In some cases homogeneous electrolysis is applied, where the two-phase electrolysis did not work. Styrene epoxidation and α-bromination of ketones underwent homogeneous electrolysis at room temperature without any catalyst. The reaction was performed in CH3CN-water (3: 2) using equimolar amount of NaBr as an electrolyte to get 68% of styrene epoxide. Use of an ionic liquid 1-butyl 3-methyl imidazolium bromide (Bmim) Br, instead of NaBr improved the yield and current efficiency of styrene epoxide to 86%.
Keywords: Two-phase Electrolysis; Oxidation; Chlorination; Bromination; Aromatic Compounds; Current Density; Electrolyte; Selectivity

We present a detailed analysis of Wertheim’s multi-density formulation for the thermodynamic properties of associating fluids with a single attraction site. Graphical expressions are explicitly illustrated for the partition function, multi-densities and direct correlation functions, and they are compared with those from the classical single-density formulation of simple fluids. The steric incompatibility among three monomers greatly simplifies cluster integrals of associating fluids, which allows dimerizing association only. Graphical expressions for the pressure and the Helmholtz energy are derived by using functional derivatives, which provide a theoretical base for TPT and SAFT equations of state.
Keywords: Associating Fluid; Graph Theory; Cluster Integral; Multi-density; TPT; SAFT

Quantitative analysis of microbial community structure in two-phase anaerobic digesters treating food wastewater by Woong Kim; Byung-Gon Ryu; Sungwhan Kim; Sung-Woon Heo; Donghyun Kim; Jungmin Kim; Haechan Jo; Jong-Hee Kwon; Ji-Won Yang (381-385).
An acidogenic reactor with a 0.5-L working volume and a methanogenic digester with a 5-L of working volume were operated for 150 days on a continuous mode to investigate the structure of a microbial community during food wastewater treatment. During the steady state of anaerobic digestion, volatile solids (VS) removal efficiency in the pilot plant was approximately 65%. The bacterial population was higher than any other methanogens detected during the entire anaerobic process and treatment of raw food wastewater. Methanomicrobiales (MMB), Methanosarcinales (MSL), and Methanobacteriales (MBT) were detected during digestion. The methanogenic population present in the acidogenic reactor was directly affected by the archaeal community in raw food wastewater. However, the shift of microbial community in the methanogenic digester was relatively gradual. The performance of methanogenic digester might be more related to the change of microbial metabolism affected by the physicochemical properties of the input substrate.
Keywords: Food Wastewater; Anaerobic Digestion; Methanobacteriales ; Methanomicrobiales ; Methanosarcinales

Nitrate control strategies in an activated sludge wastewater treatment process by Wenhao Shen; Erpan Tao; Xiaoquan Chen; Dawei Liu; Hongbin Liu (386-392).
We studied nitrate control strategies in an activated sludge wastewater treatment process (WWTP) based on the activated sludge model. Two control strategies, back propagation for proportional-integral-derivative (BP-PID) and adaptive-network based fuzzy inference systems (ANFIS), are applied in the WWTP. The simulation results show that the simple local constant setpoint control has poor control effects on the nitrate concentration control. However, the ANFIS (4*1) controller, which considers not only the local constant setpoint control of the nitrate concentration, but also three important indices in the effluent—ammonia concentration, total suspended sludge concentration and total nitrogen concentration—demonstrates good control performance. The results also prove that ANFIS (4*1) controller has better control performance than that of the controllers PI, BP-PID and ANFIS (2*1), and that the ANFIS (4*1) controller is effective in improving the effluent quality and maintaining the stability of the effluent quality.
Keywords: Nitrate; Control; Wastewater; Simulation; Environment; Numerical Analysis

Design and implementation of an integrated safety management system for compressed natural gas stations using ubiquitous sensor network by Jae Mo Yang; Byung Seok Ko; Chulhwan Park; Byungtae Yoo; Dongil Shin; Jae Wook Ko (393-401).
To increase awareness of safety in facilities where hazards may exist, operators, managers, and executive officers on the site should be able to monitor such facilities. However, most compressed natural gas (CNG) service stations in Korea use only local-mode monitoring, with only on-site operators to monitor the facility. To complement this local-mode monitoring, an online safety management system called Ubiquitous-gas safety management system (U-GSMS) was developed. The U-GSMS consists largely of software and hardware. The software consists of systems that can manage safety and operations, while the hardware consists of sensors installed in the gas facility and wireless communication systems using a ubiquitous sensor network (USN) technology that facilitates communication between sensors as well as between sensors and other devices. As these systems are web-based, on-site operators as well as managers and executive officers at the headquarters can more effectively and efficiently perform monitoring and safety management.
Keywords: Safety Management System; Compressed Natural Gas (CNG); Ubiquitous Sensor Network (USN); Quantitative Risk Assessment (QRA); Emergency Response; Quantitative Management Assessment (QMA)

Pressure distribution and wall shear stress in stenosis and abdominal aortic aneurysm by computational fluid dynamics modeling (CFD) by Jong-Beum Choi; Young-Ran Park; Shang-Jin Kim; Hyung-Sub Kang; Byung-Yong Park; In-Shik Kim; Yeong-Seok Yang; Gi-Beum Kim (402-411).
The models of stenosed blood vessel with three different types of stenosis types have been modeled to investigate blood flow characteristics. The study was performed to investigate various hemodynamics, such as pressure and wall shear stress (WSS), with the change of stenosis ratio and Reynolds numbers (Re). The results of modeling, the minimum WSS occurred in different regions according to the stenosis types. The change of the diameter of blood vessel showed up in the pre-stenotic region by elastic behavior characteristics of blood vessels. Also, when the thickness of wall of blood vessel is 2 mm, the radius of blood vessel is increased by approximately two-times. As atherosclerosis progresses, the wall of blood vessels gradually loses elasticity and then the thickness of blood vessels gets thinner.
Keywords: Abdominal Aortic Aneurysm; Computational Fluid Dynamics (CFD); Atherosclerosis; Shear Stress

Reactor sizing for butane steam reforming over Ni and Ru catalysts by Minjun Seong; Mi Shin; Jung-Ho Cho; Young-Chul Lee; Young-Kwon Park; Jong-Ki Jeon (412-418).
We obtained kinetics data on steam reforming of butane and calculated the appropriate reactor size based on the kinetics data. Using commercial Ni and Ru catalysts, steam reforming reactions of butane were performed while changing the reaction temperature and partial pressure of reactants. After comparing the power law model and the Langmuir-Hinshelwood model by using the kinetics data obtained from the experiment, it is revealed that the reaction rate could be determined by both models in the reforming reaction of butane over commercial Ni and Ru catalysts. Also, calculation of the steam reforming reactor size using a PRO/II simulation with a kinetic model equation showed that the reactor size using the Ni catalyst is smaller than that with the Ru catalyst to obtain the same conversion.
Keywords: Steam Reforming; Butane; Reaction Kinetics; Reactor Sizing; Simulation

Kinetic modeling of hydrocracking reaction in a trickle-bed reactor with Pt/Y-zeolite catalysts by BalSang Lee; Myung-June Park; Young-A Kim; Eun Duck Park; Jeongsik Han; Kwang-Eun Jeong; Chul-Ung Kim; Soon-Yong Jeong (419-426).
A kinetic model is developed to predict the entire distribution of hydrocarbon products for the hydrocracking reaction with Pt/Y-zeolite catalysts in a trickle-bed reactor. Operating conditions, such as temperature, pressure, and wax and H2 flow rates were varied to evaluate their effects on conversion and distribution, and kinetic parameters were estimated using the experimental data that covers the window of operating conditions. The comparison between experimental data and simulated results corroborated the validity of the developed model, and the quantitative prediction of the reactor performance was clearly demonstrated. To make evident the usefulness of the model, an optimization method, genetic algorithm (GA), was applied, and the optimal condition for the maximum production of C10-C17 was successfully calculated.
Keywords: Hydrocracking; Pt/Y-zeolite Catalyst; Kinetic Modeling; Parameter Estimation; Optimization

Transesterification of dimethyl carbonate (DMC) with hydrogenated bisphenol A (HBPA) was studied over various organotin oxides under pressured condition without removal of by-producing methanol. Bu2SnO displayed higher activities in HBPA conversion and bis-methylcarbonate of hydrogenated bisphenol-A (BMHBPA) synthesis, and HBPA conversion and BMHBPA selectivity reached 97.4% and 84.0%. However, when Ph2SnO was used as catalyst, HBPA conversion and BMHBPA selectivity decreased to 81.5 and 37.7%. Catalyst steric hindrance significantly influenced HBPA conversion and BMHBPA formation, and π-d interaction between phenyl ring and Sn was unfavorable for the transesterification of HBPA with DMC. Moreover, the catalytic system was further optimized.
Keywords: Transesterification; Dimethyl Carbonate; Hydrogenated Bisphenol A; Organotin Oxide; XPS

An acidic ionic liquid-conventional alkali-catalyzed biodiesel production process by Yasir Ali Elsheikh; Zakaria Man; Faheem Hassan Akhtar (431-435).
A study was undertaken to prepare biodiesel via two-step process using ionic liquid as first step catalyst due to the unsuitability of using the straight alkaline-catalyzed transesterification of high FFA presented in crude palm oil (CPO). In the first step, esterification of the FFA presented in the CPO was carried out using butylimidazolium hydrogen sulfate (BIMHSO4), in which the acid value was reduced from 6.93 to 1.02mg KOH/g and then, KOH-catalyzed transesterification was applied. The conversion rate of FFA attained 85.3% when 4.8 wt% of BIMHSO4 was applied to the reaction system containing methanol to CPO ratio of 12: 1 reacted at 170 °C for 150min. The final yield in 97.3% revealed that the process proposed in this study could lead to an excellent biodiesel meeting the ASTM requirements. Furthermore, this new two-step catalysis process could solve the old conventional catalysis process drawbacks.
Keywords: Crude Palm Oil; Ionic Liquid; Biodiesel; BIMHSO4 ; Esterification; Transesterification

The hydrodynamic characteristic performance of an internal draft tube inverse fluidized bed biofilm reactor was studied for the aerobic biodegradation of phenol (1,200 mg/l) using Pseudomonas fluorescens for various ratios of settled bed volume to reactor working volume (V b /V r ) under batchwise condition with respect to liquid phase. The operating parameters, such as superficial gas velocity, phase hold ups, aspect ratio and bed height, were analyzed for different ratios of (V b /V r ). The effect of biodegradation on synthetic phenolic effluent was determined from the reduction in chemical oxygen demand and phenol removal efficiency. The optimum value of (V b /V r ) m was 0.20 for the optimal superficial gas velocity, U gm =0.220 m/s with the COD reduction efficiency of 98.5% in 48 hours. The biomass and biofilm characteristics of P. fluorescens were determined for optimal hydrodynamic operating parameters by evaluating its biofilm dry density and thickness, bioparticle density, suspended and attached biomass concentration.
Keywords: Fluidized Bed; Hydrodynamics; Hold Up; Phenol; Degradation

Waste crab shells were used as an adsorbent to efficiently adsorb silver ions in actual industrial wastewater. The functional groups like -NHCO or -NO2 groups in crab shells play an important role in the adsorption of silver ions. The highest removal efficiency was about 96% obtained from the 30 g/L of adsorbent concentration at initial pH 6.0 of waste solution. Langmuir sorption model was chosen to estimate the maximum uptake capacity and affinity constant of waste crab shells for silver ions, and its value was 5.21mg/g-dry mass and 0.411 L/mg, respectively. Entire adsorption process was completed in 60 min, and removal efficiency of crab shells was higher than that of Amberlite IR 120 plus resin. The effect of temperature could be neglected in the range of 15.0–45.0 °C. Also, instrumental analysis such as SEM (scanning electron microscopy) photographs, EDX (energy dispersive X-ray) spectrum, and FT-IR spectrum were applied to investigate the surface condition and functional groups of crab shells.
Keywords: Crab Shells; Silver Ions; Adsorption; Wastewater; Recovery

Recovery of copper from a surface altered chalcopyrite contained ball mill spillage through bio-hydrometallurgical route by Sandeep Panda; Pradeep Chandra Rout; Chinmaya Kumar Sarangi; Srabani Mishra; Nilotpala Pradhan; Umaballav Mohapatra; Tondepu Subbaiah; Lala Behari Sukla; Barada Kanta Mishra (452-460).
Bioleaching studies for chalcopyrite contained ball mill spillages are very scarce in the literature. We developed a process flow sheet for the recovery of copper metal from surface activated (600 °C, 15 min) ball mill spillage through bio-hydrometallurgical processing route. Bioleaching of the activated sample using a mixed meso-acidophilic bacterial consortium predominantly A. ferrooxidans strains was found to be effective at a lixiviant flow rate of 1.5 L/h, enabling a maximum 72.36% copper recovery in 20 days. Mineralogical as well as morphological changes over the sample surface were seen to trigger the bioleaching efficiency of meso-acidophiles, thereby contributing towards an enhanced copper recovery from the ball mill spillage. The bio-leach liquor containing 1.84 g/L Cu was purified through solvent extraction using LIX 84I in kerosene prior to the recovery of copper metal by electrowinning. Purity of the copper produced through this process was 99.99%.
Keywords: Spillage; Thermal Activation; Acidithiobacillus ferrooxidans ; BACFOX; Solvent Extraction; Electrowinning

Fluoride removal from diluted solutions by Donnan dialysis using full factorial design by Ali Boubakri; Nawel Helali; Mohamed Tlili; Mohamed Ben Amor (461-466).
Excessive fluoride concentration in potable water can lead to fluorosis of teeth and bones. In the present study, Donnan dialysis (DD) is applied for the removal of fluoride ions from diluted sodium fluoride solutions. A four factor two level (24) full factorial design was used to investigate the influence of different physico-chemical parameters on fluoride removal efficiency (Y F ) and fluoride flux (J F ) through anion exchange membrane. The statistical design determines factors which have the important effects on Donnan dialysis performance and studies all interactions among the considered parameters. The four significant factors were initial fluoride concentration, feed flow rate, temperature and agitation speed. The experimental results and statistical analysis show that the temperature and agitation speed have positive effects on fluoride removal efficiency and the initial fluoride concentration has a negative effect. In the case of fluoride flux, feed flow rate and initial concentration are the main effect and all factors have a positive effect. The interaction between studied parameters was not negligible on two responses. A maximum fluoride removal of 75.52% was obtained under optimum conditions and the highest value of fluoride flux obtained was 2.4 mg/cm2·h. Empirical regression models were also obtained and used to predict the flux and the fluoride removal profiles with satisfactory results.
Keywords: Fluoride Removal; Fluoride Flux; Donnan Dialysis; Anion Exchange Membrane; Factorial Design

A new approach to modification of an agro-based raw material for Pb(II) adsorption by Muhammad Salman; Makshoof Athar; Umar Farooq; Sadaf Rauf; Umy Habiba (467-474).
This paper describes a relatively new and effective modification with thiourea of an agro-based raw material, sorghum biomass for adsorption of Pb(II) ions. The modification was done under microwave irradiation. Changes in characteristics of modified material were determined by FT-IR and CHNS analysis. Effect of adsorbent dosage, contact time, solution pH and temperature on equilibrium process was extensively studied. Famous equilibrium models (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich) in non-linear fashion were applied to evaluate the equilibrium data using different initial concentrations of Pb(II) ranging from 20 mg/L to 300mg/L. The adsorption process followed the pseudosecond-order kinetics. This paper also discusses the thermodynamic parameters (free energy, enthalpy and entropy) and reveals that the adsorption process is spontaneous. An appreciable increase in adsorption capacity of the modified adsorbent was observed, depicting the advantages of thiourea modification of sorghum biomass under microwave irradiation.
Keywords: Modification; Thiourea; Non-linear Modeling; Microwave Irradiation; Reaction Kinetic; Thermodynamics

Pseudomonas sp. SMIC-3 grown on NMP was physiologically differentiated from that on glucose. Growth of SMIC-3 in an NMP-defined medium was approximately three times lower than that in a glucose-defined medium. Methylamine and 1-methyl succinimide were detected in culture fluid of SMIC-3 grown in an NMP-defined medium. Methylamine content in the culture fluid was very similar to NMP consumed by SMIC-3, but 1-methyl succinimide content was much less than the consumed NMP. Crude enzyme isolated from SMIC-3 grown on NMP catalyzed production of methylamine, 1-methyl succinimide, and succinate from NMP but that on glucose did not. Crude enzyme isolated from SMIC-3 grown on glucose and NMP commonly catalyzed dehydrogenation of pyruvate, isocitrate, and malate coupled to reduction of NAD+ to NADH. 2D-SDS-PAGE pattern of total soluble proteins isolated from SMIC-3 grown on glucose was significantly different from that on NMP. Physiological function of SMIC-3 for catabolizing NMP may be selectively induced and activated by NMP.
Keywords: Pseudomonas sp.; 1-Methyl-2-pyrrolidinone; 1-Methyl Succinimide; Methylamine; 2D-SDS-PAGE

Enhanced skin delivery and characterization of rutin-loaded ethosomes by Soo Nam Park; Hye Jin Lee; Hyun A. Gu (485-489).
We formulated rutin-loaded ethosomes and compared their vesicle size, loading efficiency, stability, and elasticity. In addition, an in vitro skin penetration experiment was performed. The results of the study indicated that ethosomes loaded with 0.005–0.03% rutin were stable during the four-week study period. Among them, those loaded with 0.03% rutin showed a vesicle size (190.20±14.57 nm) and loading efficiency (73.77%±0.01%). Therefore, the in vitro skin penetration experiment was performed using 0.03% rutin-loaded ethosome. Compared to an ethanolic solution of rutin (44.16%), rutin-loaded liposome (37.80%), and a distilled water (DW) solution of rutin (18.31%), rutin-loaded ethosome (93.31 μg; 61.30%) was superior in delivering rutin. Therefore, we suggest that ethosome loaded with 0.03% rutin enhance the skin penetration of rutin and may be used as a drug delivery system for natural cosmetic materials such as flavonoids.
Keywords: Ethosome; Rutin; Skin Penetration; Cosmetic Material; Elasticity

Isolation and characterization of thermostable phycocyanin from Galdieria sulphuraria by Myounghoon Moon; Sanjiv K. Mishra; Chul Woong Kim; William I. Suh; Min S. Park; Ji-Won Yang (490-495).
Phycocyanin is a highly valuable pigmented protein synthesized by several species of cyanobacteria and red alga. In this study we demonstrate the production of thermostable phycocyanin from the unicellular red alga Galdieria sulphuraria. Phycocyanin was extracted by repeated freeze-thaw cycles and purified in a two-step process using ammonium sulfate fractionation, at 25% and 50% concentrations. Purified phycocyanin exhibited maximum absorbance at 620 nm, and the purity ratio (A620/A280) was found to be greater than 4. The recovery efficiency of phycocyanin from the crude extract was above 80%. In total, approximately 19 milligram pure phycocyanin was obtained from 3 g of wet cell mass of Galdieria sp. Subunits α and β of the protein were separated by SDS-PAGE and analyzed by MALDITOF mass spectrometry for identification, which confirmed that the isolated protein is phycocyanin. The molecular weight of α and β subunits of phycocyanin was found to be 17.6 and 18.4 kDa, respectively.
Keywords: Galdieria sulphuraria ; Red Algae; Value-added Product; Phycocyanin; Purification

Genetic optimization of neural network and fuzzy logic for oil bubble point pressure modeling by Mohammad Afshar; Amin Gholami; Mojtaba Asoodeh (496-502).
Bubble point pressure is a critical pressure-volume-temperature (PVT) property of reservoir fluid, which plays an important role in almost all tasks involved in reservoir and production engineering. We developed two sophisticated models to estimate bubble point pressure from gas specific gravity, oil gravity, solution gas oil ratio, and reservoir temperature. Neural network and adaptive neuro-fuzzy inference system are powerful tools for extracting the underlying dependency of a set of input/output data. However, the mentioned tools are in danger of sticking in local minima. The present study went further by optimizing fuzzy logic and neural network models using the genetic algorithm in charge of eliminating the risk of being exposed to local minima. This strategy is capable of significantly improving the accuracy of both neural network and fuzzy logic models. The proposed methodology was successfully applied to a dataset of 153 PVT data points. Results showed that the genetic algorithm can serve the neural network and neurofuzzy models from local minima trapping, which might occur through back-propagation algorithm.
Keywords: Genetic Algorithm; Optimized Neural Network; Optimized Fuzzy Logic; Local Minima; Bubble Point Pressure of Crude Oils

Present work involves synthesis of NiO nanoparticles using chemical homogeneous precipitation (CHP) method as a facile procedure. Ammonia as a complex agent was used in this method. Effects of different types of complexation-precipitation methods on the crystallinity and morphology of nanoparticles were investigated. NiO particles were prepared by direct precipitation method from NiSO4 solution to compare crystallinity and morphology of NiO particles with particles obtained via complexation-precipitation methods. Our major intent was to investigate the effect of complex agent on the crystallization and growth of NiO nanoparticles. Results showed that the best condition for synthesizing spherical NiO shape was using NaOH as decomposing agent, of which the consequence was more uniformity and spherical nanoparticles with a diameter in the range of 40–60 nm. The size of the nickel oxide and nickel hydroxide nanoparticles was estimated by X-ray powder diffraction (XRD) pattern. The chemical structure information of the particles was studied by Fourier transform infrared (FT-IR) spectroscopy. Spherical, elliptical, sheet or flowerlike shapes were detected by field emission scanning electron microscopy (FESEM) analysis. Results showed that by the use of ammonia as complex agent, crystalline state and particles size distribution of NiO nanoparticles improved.
Keywords: Complex Precipitation; Nickel Oxide; Nanoparticles; Nickel Hydroxide; Chemical Homogeneous Precipitation (CHP)

Lipid extraction from natural plant source of Adenanthera pavonina using mixed solvent by superheated extractor by Ramachandran Kasirajan; Sivakumar Pandian; Suganya Tamilarasan; Renganathan Sahadevan (509-513).
The lipid content was extracted from the saga seed by superheated condition and soxhlet apparatus. The mixture of hexane, chloroform and methanol was utilized as a mixed solvent for these extraction operations. Different parameters such as different solvent, temperature, mean particle size and solvent flow have been examined. The optimized lipid extraction was achieved as 26.2 wt% by using superheated condition from the saga seed powder at 90 °C for 120min. Then the fatty acids profile of the optimized Adenanthera pavonina oil were analyzed by gas chromatography. Unsaturated fatty acid was high as 83.7% compared with saturated fatty acid barely 15.4% by relative.
Keywords: Adenanthera pavonina ; Saga Seed; Mixed Solvents and Solvents Superheated Extraction

Poly-Ethylene Glycol (PEG) 300+H2O solutions (PEGWs) has been used as a promising medium for the absorption of SO2. We investigated the UV, FTIR, 1H-NMR, and fluorescence spectra in the absorption processes of SO2 in PEGWs to present an important absorption mechanism. Based on the spectral results, the possibility of intermolecular hydrogen bond formation by hydroxyl oxygen atom in the PEG molecule with hydrogen atom in H2O and S…O interaction formation by the oxygen atoms in PEG with the sulfur atom in SO2 are discussed. This shows that the spectral changes may be due to the formation of -CH2CH2O(H)…HOH… and -CH2-CH2-O(CH2-CH2-)…HOH… in PEGWs and the formation of -CH2CH2OH…OSO…, and intermolecular S…O interaction between PEG and SO2 as the formation of -CH2CH2OCH2CH2O(H)…(O)S(O)… and -CH2-CH2-O(CH2-CH2-)…(O)S(O)…. The existence of these bonds benefits the absorption and desorption processes of SO2 in PEGWs.
Keywords: Poly-ethylene Glycol (PEG) 300; Sulfur Dioxide; Absorption; Hydrogen Bonding; S…O Interaction

Experimental data of high pressure phase behavior from 313.2 to 393.2 K and pressures up to about 14.3 MPa were reported for binary mixture of 2,2,3,3,4,4,4-heptafluorobutyl acrylate (HFBA) and 2,2,3,3,4,4,4-heptafluorobutyl methacrylate (HFBMA) in supercritical carbon dioxide. The high pressure experiment was performed by static method using variable-volume view cell apparatus. The CO2+HFBA and CO2+HFBMA systems are correlated with the Peng-Robinson equation of state using a van der Waals one-fluid mixing rule. The CO2+HFBA and CO2+HFBMA systems exhibit type-I phase behavior with continuous critical mixture curves.
Keywords: Carbon Dioxide; 2,2,3,3,4,4,4-Heptafluorobutyl Acrylate; 2,2,3,3,4,4,4-Heptafluorobutyl Methacrylate; High Pressure Phase Behavior; Peng-Robinson EOS

Plasma-polymerized n-hexane and its utilization as multilayer moisture-barrier film with aluminum oxide by Kyu-Hyun Hwang; Seung-Woo Seo; Eun Jung; Heeyeop Chae; Sung Min Cho (528-531).
Organic-inorganic multilayer structures were prepared for a moisture barrier. As the organic polymer and inorganic layers, plasma-polymerized n-hexane and aluminum-oxide layers were utilized, respectively. The plasma polymerization of n-hexane was confirmed by the appearance of carbon double bonds in the produced polymer layer. The organic and inorganic layers were prepared sequentially in vacuum, and the repeated growth sequence produced the multilayer structures. The organic-inorganic multilayer structures show about 35% better moisture-barrier property than those obtained from individual organic and inorganic layers.
Keywords: Moisture Barrier; Plasma Polymer; Hexane; Multilayer; Atomic Layer Deposition

Bulk and rheological properties of polyacrylamide hydrogels for water shutoff treatment by Asefe Mousavi Moghadam; Mohsen Vafaie Sefti; Mahsa Baghban Salehi; Hasan Naderi (532-539).
Presenting an optimal hydrogel for water shutoff, based on the bulk and rheological properties, was the main purpose of this research. To determine gelation time, a bottle test was conducted using central composite design method with two factors, AN125VLM and Cr(OAc)3, as copolymer and crosslinker, respectively. To select hydrogel with high strength network, crosslinking density and consistency modulus were also measured. Hence, a hydrogel with 26,340 ppm concentration of copolymer, 0.12 ratio of crosslinker/copolymer, maximum value of crosslinking density (1,950) and consistency modulus (31,900 Pa) was selected as the optimal one. To study the gelation time among different factors in porous media, rheological experiments were carried out by Plackett-Burman design to screen the eight factors (NaCl, CaCl2, KCl and MgCl2 concentrations, temperature, pH, sodium lactate and nanoclay). Accordingly, temperature was the most effective factor controlling the gelation time, while pH and other factors had negligible effect on the gelation time of the optimal hydrogel.
Keywords: Hydrogel; Bottle Test; Rheological Tests; Crosslinking Density; Consistency Modulus; Central Composite Design; Plackett-Burman Design