DOI
 | ryusoff@um.edu.my |
Journal articles | |
2012 |
S Shahla, G C Ngoh, R Yusoff (2012) Optimization of base-catalyzed ethyl ester production from palm oil Asia-Pacific Journal of Chemical Engineering 7: Abstract: Plant-based ethyl esters can be used directly as biodiesel or as a bio-resource for other industries such as lubricant and detergents. In this work, production of ethyl ester from chemical transesterification of palm oil with ethanol using sodium ethoxide as catalyst has been optimized by Box-Behnken design and response surface methodology. Catalyst concentration was found to be the most significant parameter affecting the conversion rate of the reaction. The interaction of temperature and molar ratio of ethanol to palm oil had minor effect on the conversion rate. A reduced cubic model was developed to navigate the design space. It was predicted by the model at optimum reaction conditions, that is 1.2?wt% of sodium ethoxide and 12:1 molar ratio of ethanol to oil at 25?degrees C, that as high as 98% ethyl ester can be achieved. It was then verified experimentally that close to 100% conversion rate is achievable under these optimum conditions. (c) 2011 Curtin University of Technology and John Wiley & Sons, Ltd. Notes: Suppl. 1 Sp. Iss. SI 912DA Times Cited:0 Cited References Count:25
|
|
Aziz, Noorhaliza, Yusoff, Rozita, Aroua, Mohamed Kheireddine (2012) Absorption of CO2 in aqueous mixtures of N-methyldiethanolamine and guanidinium tris(pentafluoroethyl)trifluorophosphate ionic liquid at high-pressure Fluid Phase Equilibria 322-323: 120-125 Abstract: In this paper, the solubility of CO 2 in aqueous blends of N-methyldiethanolamine (MDEA) and guanidium tris(pentafluoroethyl)trifluorophosphate [gua] +[FAP] - ionic liquid was measured at 313.15, 333.15 and 353.15K and at partial pressures up to 3MPa. Reported data were loading capacity (mol CO 2/total mol) as a function of CO 2 partial pressure at equivalent temperature. A simple correlation was used to predict the solubility of CO 2 in the mixtures. The predicted data showed good agreement with the experimental data. In this study, it has been found that adding [gua] +[FAP] - into the aqueous MDEA has lowered the absorption capacity and this effect was significant at higher concentrations. Notes: Export Date: 2 January 2013 Source: Scopus CODEN: FPEQD Language of Original Document: English Correspondence Address: Yusoff, R.; Chemical Engineering Department, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia; email: ryusoff@um.edu.my References: Kohl, A.L., Nielsen, R.B., (1997), Gas Purification 5th Edition, Gulf Publishing CompanyDupart, M.S., Bacon, T.R., Edwards, D.J., (1993) Hydrocarbon Processing, pp. 75-80; Dupart, M.S., Bacon, T.R., Edwards, D.J., (1993) Hydrocarbon Processing, pp. 89-94; Stewart, E.J., Lanning, R.A., (1994) Hydrocarbon Processing; Blanchard, L.A., Hancu, D., Beckman, E.J., Brennecke, J.F., (1999) Nature, 398, pp. 28-29; Deetlefs, M., Seddon, K.R., (2006) Chim. Oggi, 24, pp. 16-23; Welton, T., Wasserscheid, P., Ionic Liquids in Synthesis (2008), Wiley-VCH Verlag GmbH & Co. KGaAZhang, S., Yuan, X., Chen, Y., Zhang, X., (2005) J. Chem. Eng. Data, 50, pp. 1582-1585; Yuan, X., Zhang, S., Chen, Y., Lu, X., Dai, W., Mori, R., (2006) J. Chem. Eng. Data., 51, pp. 645-647; Shiflett, M.B., Yokozeki, A., (2009) Energy Fuels, 24, pp. 1001-1008; Shariati, A., Peters, C.J., (2003) J. Supercrit. Fluids, 25, pp. 109-117; Shariati, A., Peters, C.J., (2004) J. Supercrit. Fluids, 30, pp. 139-144; Shariati, A., Peters, C.J., (2004) J. Supercrit. Fluids, 29, pp. 43-48; Shariati, A., Peters, C.J., (2005) J. Supercrit. Fluids, 34, pp. 171-176; Gutkowski, K.I., Shariati, A., Peters, C.J., (2006) J. Supercrit. Fluids, 39, pp. 187-191; Anthony, J.L., Anderson, J.L., Maginn, E.J., Brennecke, J.F., (2005) J. Phys. Chem. B, 109, pp. 6366-6374; Kim, Y.S., Choi, W.Y., Jang, J.H., Yoo, K.P., Lee, C.S., (2005) Fluid Phase Equilib., pp. 439-445; Muldoon, M.J., Aki, S.N.V.K., Anderson, J.L., Dixon, J.K., Brennecke, J.F., (2007) J. Phys. Chem. B, 111, pp. 9001-9009; Aki, S.N.V.K., Mellein, B.R., Saurer, E.M., Brennecke, J.F., (2004) J. Phys. Chem. B, 108, pp. 20355-20365; Bates, E.D., Mayton, R.D., Ntai, I., Davis, J.H., (2002) J. Am. Chem. Soc., 124, pp. 926-927; Galán Sánchez, L.M., Meindersma, G.W., de Haan, A.B., (2007) Chem. Eng. Res. Des., 85, pp. 31-39; Bara, J.E., Camper, D.E., Gin, D.L., Noble, R.D., (2009) Acc. Chem. Res., 43, pp. 152-159; Bara, J.E., Carlisle, T.K., Gabriel, C.J., Camper, D., Finotello, A., Gin, D.L., Noble, R.D., (2009) Ind. Eng. Chem. Res., 48, pp. 2739-2751; Feng, Z., Cheng-Gang, F., You-Ting, W., Yuan-Tao, W., Ai-Min, L., Zhi-Bing, Z., (2010) Chem. Eng. J., 160, pp. 691-697; Zhao, Y., Zhang, X., Zeng, S., Zhou, Q., Dong, H., Tian, X., Zhang, S., (2010) J. Chem. Eng. Data, 55, pp. 3513-3519; Aparicio, S., Atilhan, M., (2010) Energy Fuels, 24, pp. 4989-5001; Zhang, X., Liu, Z., Wang, W., (2008) AIChE J., 54, pp. 2717-2728; Sairi, N.A., Yusoff, R., Alias, Y., Aroua, M.K., (2011) Fluid Phase Equilib., 300, pp. 89-94; Jou, F.Y., Mather, A.E., Otto, F.D., (1982) Ind. Eng. Chem. Process Des. Dev., 21, pp. 539-544; Jou, F.Y., Mather, A.E., (2005) Fluid Phase Equilib., 228-229, pp. 465-469; Ahmady, A., Hashim, M.A., Aroua, M.K., (2011) Fluid Phase Equilib., 309, pp. 76-82; Ahmady, A., Hashim, M.A., Aroua, M.K., (2010) J. Chem. Eng. Data, 55, pp. 5733-5738; Rho, S.-W., Yoo, K.-P., Lee, J.S., Nam, S.C., Son, J.E., Min, B.-M., (1997) J. Chem. Eng. Data, 42, pp. 1161-1164; Haji-Sulaiman, M.Z., Aroua, M.K., Benamor, A., (1998) Chem. Eng. Res. Des., 76, pp. 961-968; Kuranov, G., Rumpf, B., Smirnova, N.A., Maurer, G., (1996) Ind. Eng. Chem. Res., 35, pp. 1959-1966
| |
|
S Shahla, G C Ngoh, R Yusoff (2012) The evaluation of various kinetic models for base-catalyzed ethanolysis of palm oil Bioresource Technology 104: 1-5 Abstract: In this paper, the kinetics of palm oil ethanolysis with various models have been investigated in a temperature range of 25-55 degrees C. The highest yield was achieved when the conversion to ethyl ester was 97.5+/-0.5% in the stated temperature range, using ethanol:oil molar ratio of 12:1, and 1.0 wt.% sodium ethoxide. The level of conformity of the reaction with reversible second order, irreversible second order and first order kinetic models were evaluated by means of the R-2 values of the linear curves. The ethanolysis showed the best conformity with irreversible second order kinetic model with 92-98% level of confidence. The reaction rate constants were within 0.018-0.088 dm(3)/mol min and the activation energy of the reaction was 42.36 kJ/mol. (C) 2011 Elsevier Ltd. All rights reserved. Notes: Shahla, Sanaz Ngoh, Gek Cheng Yusoff, Rozita
| |
|
M H Chakrabarti, M Ali, J N Usmani, N A Khan, D B Hasan, M S Islam, A A Abdul Raman, R Yusoff, M F Irfan (2012) Status of biodiesel research and development in Pakistan Renewable and Sustainable Energy Reviews 16: 7. 4396-4405 Abstract: Performance of biodiesel in engines is well established and biodiesel is currently adjudged as a low carbon fuel with the most potential of replacing fossil fuels. The fossil fuel sources are dwindling in Pakistan resulting in importation of about 8.1 million tonnes at approximately US$ 9.4 billion per annum. In the ambit of this justification, augmenting the energy scarce resources in Pakistan through intense harnessing of the varied biodiesel sources can adequately address the deficiency and can ensure energy security. Towards this end, the progress attained in biodiesel related researches in Pakistan are evaluated and presented with the view of highlighting ways of achieving the target set by the Government. A feedstock that drew less attention is spent triglycerides, and the little work reported by some organizations appeared promising. Now the onus is upon organizations such as the Alternative Energy Development Board and Pakistan State Oil to harness the research results from several indigenous Universities and develop a full-scale biodiesel economy in Pakistan. é 2012 Elsevier Ltd. All rights reserved. Notes:
| |
|
C H Chan, G C Ngoh, R Yusoff (2012) A brief review on anti diabetic plants : Global distribution, active ingredients, extraction techniques and acting mechanisms Pharmacognosy Reviews 6: 11. 22-28 Abstract: A study has been conducted with the aim to provide researchers with general information on anti diabetic extracts based on relevant research articles collected from 34 reliable medical journals. The study showed that Asian and African continents have 56% and 17% share of the worldwide distribution of therapeutic herbal plants, respectively. In Asia, India and China are the leading countries in herbal plants research, and there has been an increase in medicinal research on plants extract for diabetes treatment since 1995 in these regions. The information collected shows that plant leaves are about 20% more favorable for storing active ingredients, as compared to other parts of herbal plants. A brief review on the extraction techniques for the mentioned parts is also included. Furthermore, the acting mechanisms for the anti diabetic activity were described, and the related active ingredients were identified. The findings reveal that most of the anti diabetic research is focused on the alteration of glucose metabolism to prevent diabetes. Notes: Chan, Chung-Hung Ngoh, Gek-Cheng Yusoff, Rozita eng India 2012/06/02 06:00 Pharmacogn Rev. 2012 Jan;6(11):22-8. doi: 10.4103/0973-7847.95854.
| |
 | |
|
Abstract: Recently, aqueous mixtures of alkanolamines and ionic liquids had emerged as potential solvents for CO2 capture. Solubility data of CO2 in aqueous mixtures of monoethanolamine (MEA) and 1-n-butyl-3-methylimidazolium tetrafluoroborate ([bmim] [BF4]) are already available in the literature. However, data on the corrosiveness of these new solvents with regards to carbon steel are still scarce. In this work, carbon steel corrosion behavior in carbonated aqueous mixtures of MEA and [bmim] [BF4] was investigated using potentiodynamic polarization and weight loss methods at fixed CO2 loading of 0.55 mol/mol. The corrosion rates were measured for [bmim] [BF4] concentration ranging from 0.1 to 1.0 M and at temperatures of 40 and 80 degrees C. Carbon steel corrosion rates obtained from the two methods are in agreement; and showed that the presence of [bmim] [BF4] in the carbonated solution has reduced the solution corrosivity to carbon steel for carbonated 4.0 M MEA/[bmim] [BF4] system, but increased that of carbonated 2.0 M MEA/[bmim][BF4] system. Scanning electron microscopy (SEM) images demonstrated that immersed specimens were severely corroded in carbonated 2.0 M MEA/[bmim] [BF4] system. While for carbonated 4.0 M MEA/[bmim] [BF4] system, a protective surface layer was formed as [bmim] [BF4] concentration and temperature increased, respectively. Notes: 958UU Times Cited:0 Cited References Count:24
| |
2011 |
N A Sairi, R Yusoff, Y Alias, M K Aroua (2011) Solubilities of CO 2 in aqueous N-methyldiethanolamine and guanidinium trifluoromethanesulfonate ionic liquid systems at elevated pressures Fluid Phase Equilibria 300: 1-2. 89-94 Abstract: In this work, the solubility of CO 2 in aqueous blended systems of N-methyldiethanolamine (MDEA) and guanidinium trifluoromethanesulfonate ([gua] +[OTf] -) have been carried out. The solubilities were measured at temperature 303.2K, 323.2K and 333.2K, over CO 2 partial pressure ranging from 500 to 3000kPa. All data were reported as loading capacity (molCO 2/total mol) as a function of partial pressure of CO 2 at the corresponding temperature. It has been found that the aqueous [gua] +[OTf] - ionic liquid gave significantly higher solubility, up to 1.63mol CO 2/total mol, as compared to other pure ionic liquids such as [bmim] +[BF 4] -, [emim] +[OTf] - and [emim] +[C 2N 3] - which recorded at 323.2K and 3000kPa. However, the addition of [gua] +[OTf] - ionic liquid to aqueous MDEA gave a slight decreased on solubility. Correlations of solubility as a function of partial pressure and temperature were obtained with deviation of ñ0.957%. é 2010 Elsevier B.V. Notes: Cited By (since 1996): 8 Export Date: 2 January 2013 Source: Scopus CODEN: FPEQD Language of Original Document: English Correspondence Address: Sairi, N.A.; Chemistry Department, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia; email: asrina_sairi@um.edu.my
|
|
C H Chan, R Yusoff, G C Ngoh, F W Kung (2011) Microwave-assisted extractions of active ingredients from plants Journal of Chromatography A 1218: 37. 6213-6225 Abstract: Microwave-assisted extraction (MAE) is widely employed in the analysis and the extraction of active compounds from plants. This review summarizes the research done during the last decade on the MAE of active ingredients from plants. Advances and modifications to improve the performance of MAE are presented and discussed in detail. Modified MAE such as vacuum microwave-assisted extraction (VMAE), nitrogen-protected microwave-assisted extraction (NPMAE), ultrasonic microwave-assisted extraction (UMAE), dynamic microwave-assisted extraction (DMAE) and other advancements in MAE are also detailed in this article. In addition, the microwave extraction procedures and the important parameters influencing its performance are also included, together with the advantages and the drawbacks of each MAE techniques. é 2011 Elsevier B.V. Notes: Chan, Chung-Hung Yusoff, Rozita Ngoh, Gek-Cheng Kung, Fabian Wai-Lee eng Review Netherlands 2011/08/09 06:00 J Chromatogr A. 2011 Sep 16;1218(37):6213-25. doi: 10.1016/j.chroma.2011.07.040. Epub 2011 Jul 23.
| |
|
H A M Haider, R Yusoff, M K Aroua (2011) Equilibrium solubility of carbon dioxide in 2(methylamino)ethanol Fluid Phase Equilibria 303: 2. 162-167 Abstract: In this paper the equilibrium solubility of carbon dioxide in 1.0 M. 2.0 M and 4.0 M 2(methylamino)ethanol (MAE) is measured at 303, 313 and 333 K. and at CO(2) partial pressures ranging from 1 to 100 kPa using stirred cell reactor. The Kent-Eisenberg model was used to predict the solubility of carbon dioxide in MAE solutions. The equilibrium constant representing hydrolysis of carbamate ion is correlated with temperature, CO(2) partial pressure and amine concentration by non-linear regression, using experimental results of carbamate ion concentrations. The model predicted results showed good agreement with the experimental solubility results. The solubility profile of CO(2) in MAE showed better performance when compared with other commercial amines. (c) 2011 Elsevier B.V. All rights reserved. Notes: 752QX Times Cited:1 Cited References Count:24
| |
|
Abstract: Carbon steel corrosion rates were measured in carbonated solution mixtures of monoethanolamine (MEA) and 1-Butyl-3-methylimidazolium dicyandiamide ([bmim] [DCA]) and MEA without [bmim] [DCA], using polarization curve and electrochemical impedance spectroscopy (EIS). Corrosion tests were carried out for 4.0 M carbonated MEA and [bmim] [DCA] concentration varied from 0.1 to 1.0 M. The CO2 loading was 0.55 mol/mol and temperature was varied from 40 to 80 oC. Results showed adding [bmim] [DCA] decreased the corrosion rate of carbon steel for 4.0 M MEA/ [bmim] [DCA] system. However, the effect of [bmim] [DCA] addition was less as the temperature increased to 80 oC. Scanning Electron Microscope (SEM) and Energy dispersive X-ray analysis (EDX) were also carried out to characterize the surface morphology and corrosion product formed on the electrode surface. The SEM and EDX spectrum showed that a protective corrosion layer was formed on the electrode surface for 4.0 M MEA/ [bmim] [DCA] system. The corrosion rate of carbon steel was also measured using EIS at 40 oC and 4.0 M MEA/ 1.0 M [bmim] [DCA] with different exposure times. It was found the corrosion rate increased at first, but decreased progressively with time. The results from EIS are consistent with those found from the polarization curve, SEM and EDX. Notes:
| |
|
Abstract: Aqueous solutions of alkanolamines are widely used for the removal of acidic gases such as H 2S, CO 2, COS and CS 2 in the sour gas treatment process. In spite of the resistance of alkanolamines to chemical breakdown, plant and laboratory reports indicate that, on prolonged use, alkanolamines may be transformed into undesirable products from which the amines are not easily recovered. This phenomenon, commonly referred to as âamine degradationâ, not only leads to amine losses, but may also contribute to operational problems such as foaming, corrosion, high solution viscosity and fouling as a result of decreasing the plant life. Amine based gas purification plants having absorption and stripping system, solvents are degraded at these two units mainly by oxidative degradation at absorber condition and thermal degradation at stripper condition. Identification of amine degradation routes, remediation of degradation, types of degradation products and studies on degradation reaction mechanism becomes essential for successful plant operation. Gas chromatography-mass spectrometry (GC-MS), ion chromatograph (IC), high performance liquid chromatography (HPLC), nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared absorption spectrometry (FT-IR) are extensively used to identify the various degradation products. A comprehensive review of the latest research activities on alkanolamines degradation, best method for identification, various properties of degradation products and their classification is presented in this paper. This study would help to develop better understanding of amine degradation. é 2011 Academic Journals. Notes: Cited By (since 1996): 2 Export Date: 2 January 2013 Source: Scopus Language of Original Document: English Correspondence Address: Ali, B. S.; Department of Chemical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia; email: sakin.chem.buet@gmail.com References: Abdi, M.A., Purification of partially degraded diethanolamine solutions, PhD thesis (1997) University of British Columbia, , UBC), Canada; Amiri, A.P., Haghighi, A.A., Ehsani, M.R., Alkanolamines foaming tendency: Effect of amine mixing, amine degradation and gas flow rate (2007) Farayandno, 8, pp. 1-6; Ariana, (2010) Fouling Effect of Degradation Products, , http://blog.unsri.ac.id/Chemeng%20Sai/opp/fouling-pada-heatexchanger/mrdetail/972/; Aroonwilas, A., Veawab, A., Characterization and comparison of the CO 2 absorption performance into single and blended alkanolamines in a packed column (2004) Ind. Eng. Chem. Res, 43, pp. 2228-2232; Bedella, S.A., Oxidative degradation mechanisms for amines in flue gas capture (2009) Energy Procedia, 1, pp. 771-778; Blauwhoff, P., Lauwhof, M.M., Verstee, G.F., Vanswaai, W.P.M., A Study on the reaction between CO and alkanolamines in aqueous solution (1984) Chemical Engineering Scienc, 3 (2), pp. 207-225; Carlson, S., Canter, S., Jenkins, J., (2001) Canadian Gas Treating Solvent Quality Control, , http://www.reclaim.com/site/reference_docs/canadian_gas_treating_solvent_quality_control.pdf; Choy, E.T., Meisen, A., Gas chromatographic detection of diethanolamine and its degradation products (1980) J. Chromatogr, 187, pp. 145-152; MDEA/Piperazine as a solvent for CO 2 capture (2009) Energy Procedia, 1, pp. 1351-1357. , Closmann F (2009). Solvent degradation MEA and MDEA/PZ blends systems. Website Closmann F, Nguyen T, Rochelle GT; (2010) Foaming Behaviour During Carbondioxide Capture, , http://www.corrosion.ksc.nasa.gov/corr_forms.htm, CRC, Retrieved on August, 2010. Website CTL. Form of corrosion; Davis, J., Rochelle, G.T., Thermal degradation of monoethanolamine at stripper conditions (2009) Energy Procedia, 1 (9), pp. 327-333; Davis, J.D., (2009) Thermal Degradation of Aqueous Amines Used For Carbon Dioxide Capture, , PhD thesis, The University of Texas at Austin; Dawodu, O.F., Meisen, A., Mechanism and kinetics of COS-induced diethanolamine degradation (1994) Ind. Eng. Chem. Res, 33, pp. 480-487; Dawodu, O.F., Meisen, A., The effects of operating conditions on COS-induced degradation of aqueous diethanolamine solutions (1992) Gas Separation & Purification, 6 (3), pp. 115-124; Dawodu, O.F., Meisen, A., Gas chromatographic analysis of alkanolamine solutions using capillary and packed columns (1993) J. Chromatogr, 629, pp. 297-307; Dawodu, O.F., Meisen, A., Identification of products resulting from carbonyl sulphide-induced degradation of diethanolamine (1991) J. Chromatogr, 587, pp. 237-246; Dawodu, O.F., Meisen, A., Effect of composition on the performance of alkanolamines blends for gas sweetening (1996) Chem. Eng. Communications, 144, pp. 103-112; Dawodu, O.F., Meisen, A., Degradation of aqueous diethanolamine solutions by carbon disulfide (1996) Gas. Sep. Purif, 10 (1), pp. 1-11; Dupart, M.S., Rooney, P.C., Bacon, T.R., (1999) Comparing Laboratory and Plant Data For MDEA/DEA Blends, , http://www.gastreating.com/pdf/Hc%20Processing%20April%201999.pdf; Eide-Haugmo, I., Brakstad, O.G., Hoff, K.A., SÞrheim, K.R., Silva, E.F.D., Svendsen, H.F., Environmental impact of amines (2009) 9, 1, pp. 1297-1304; Franco, J.A., Montigny, D., Kentisha, S.E., Perera, J.M., Stevens, G.W., Effect of amine degradation products on the membrane gas absorption process (2009) Chem. Eng. Sci, 64, pp. 4016-4023; Freeman, S.A., Davis, J., Rochelle, G.T., Degradation of aqueous piperazine in carbon dioxide capture (2010) Int. J. Greenhouse Gas Control, 4 (5), pp. 756-761; Goff, G.S., Rochelle, G.T., Monoethanolamine Degradation: O 2 Mass Transfer Effects under CO 2 Capture Conditions (2004) Ind. Eng. Chem. Res, 43, pp. 6400-6408; Goff, G.S., Rochelle, G.T., Oxidation Inhibitors for Copper and Iron Catalyzed Degradation of Monoethanolamine in CO 2 Capture Processes (2006) Ind. Eng. Chem. Res, 45, pp. 2513-2521; Haws, R., (2010) Contaminants in Amine Gas Treating, , http://www.reclaim.com/site/reference_docs/comtaminents_in_amine_gas_treating.pdf; Haws, R., Jenkins, J., (2000) Contaminant Reporting in Amine Gas Treating Service, , http://www.reclaim.com/site/reference_docs/ethylenediamines.pdf; (2009) Microfouling effect, , http://www.google.com.my/images?hl=en&q=fouling%20effect&um=1&ie=UTF-8&source=og&sa=N&tab=wi, Internet; (2010) Microfouling effect, , http://www.google.com.my/images?hl=en&q=fouling%20effect&um=1&ie=UTF-8&source=og&sa=N&tab=wi, Internet; (2010) Pitting Corrosion, , http://www.google.com.my/images?q=pitting+corrosion&um=1&hl=en&tbs=isch:1&ei=VjINTPbLJMG7rAfN9KW5Dg&sa=N&start=60&ndsp=20, Internet, retrieved on 12 August, 2010; Kennard, M., Meisen, A., Gas chromatographic technique for analyzing partially degraded diethanolamine solutions (1983) J. Chromatogr, 267, pp. 373-380; Klare, M., Scheen, J., Vogelsang, K., Jacobs, H., Broekaert, J.A.C., Degradation of short-chain alkyl- and alkanolamines by TiO 2- and Pt/TiO 2-assisted photocatalysis (2000) Chemosphere, 41, pp. 353-362; Lawal, O., Bello, A., Idem, R., The Role of Methyl Diethanolamine (MDEA) in Preventing the Oxidative Degradation of CO 2 Loaded and Concentrated Aqueous Monoethanolamine (MEA)-MDEA Blends during CO 2 Absorption from Flue Gases (2005) Ind. Eng. Chem. Res, 44, pp. 1874-1896; Lawal, O.A., Idem, R.O., Kinetics of the oxidative degradation of CO 2 loaded and concentrated aqueous MEA-MDEA blends during CO 2 absorption from flue gas streams (2006) Ind. Eng. Chem. Res, 45, pp. 2601-2607; Lensen, R., (2004) The Promoter Effect of Piperazine On the Removal of Carbon Dioxide, , http://www.bsdfreaks.nl/files/hoofd6.pdf; Lepaumier, H.D., Picq, D., Carrette, P.L., Degradation Study of new solvents for CO 2 capture in post-combustion (2009) Energy Procedia, 1, pp. 893-900; Lepaumier, H.D., Picq, D., Carrette, P.L., New Amines for CO 2 Capture I.Mechanisms of Amine Degradation in the Presence of CO 2 (2009) Ind. Eng. Chem. Res, 48, pp. 9061-9067; Lepaumier, H.D., Picq, D., Carrette, P.L., New Amines for CO 2 Capture II.Oxidative Degradation Mechanisms (2009) Ind. Eng. Chem. Res, 48, pp. 9068-9075; Lepaumiera, H.D., Picqa, D., Carrette, P.L., Degradation Study of new solvents for CO 2 capture in post-combustion (2009) Energy Procedia, 1, pp. 893-900; Mandal, B.P., Guha, M., Biswas, A.K., Bandyopadhyay, S.S., Removal of carbon dioxide by absorption in mixed amines: Modelling of absorption in aqueous MDEA/MEA and AMP/MEA solutions (2001) Chem. Eng. Sci, 56, pp. 6217-6224; Meisen, A., Abdi, M.A., (2010) Amine Degradation: Problems, , http://www.ripi.ir/congress10/amine%20degradation.pdf, Review of Research Achievements, Recovery Techniques; Meisen, A., Abdi, M.A., (2010) Amine Degradation: Problems, Review of Research Achievements, Recovery Techniques, , http://www.ripi.ir/congress10/amine%20degradation.pdf; Meisen, A., Abedinzadegan, M., Abry, R.G.F., Millard, M.G., (1996) Degraded Amine Solutions: Nature, Problems and Distillative Reclamation, , Proceedings of the 1996 Laurance Reid Gas Conditioning Conference; Oh, K.-J., Lee, S.S., Park, S.W., Park, D.W., Shon, B.H., (2003) Degradation of Aqueous Alkanolamine Solution Containing CO 2 and H 2S. Fuel Chemistry Division Preprints, 48 (1), pp. 258-259. , http://www.anl.gov/PCS/acsfuel/preprint%20archive/Files/48_1_New%20Orleans__03-03_0468.pdf; Pacheco, M.A., Kaganoi, S., Rochelle, G.T., CO 2 absorption into aqueous mixtures of diglycolamine and methyldiethanolamine (2000) Chem. Eng. Sci, 55, pp. 5125-5140; Pauley, C.R., Hashemi, R., Analysis of foaming mechanisms in amine plants (1998) URL:, , http://www.pall.com/pdf/GDS120.pdf; Rinker, E.B., (1997) PhD Dissertation, , University of California, Santa Barbara, USA; Saleem, M., Essa, M.H., Suitability for sustainable reuse of secondary effluent: A case study in Saudi Arabia, NED Univ (2010) J. Res, 7, pp. 23-34; Sexton, A.J., Rochelle, G.T., Catalysts and inhibitors for oxidative degradation of monoethanolamine (2009) Int. J. Greenhouse Gas Control, 3, pp. 704-711; Sexton, A., Rochelle, G.T., Oxidation products of amines in CO2 capture (2010) URL:, , http://www.che.utexas.edu/rochelle_group/Pubs/Pubs/SextonGHGT8.pdf; Shahi, P., Hu, Y., Chakma, A., Gas chromatographic analysis of acid gases and single/mixed alkanolamines (1994) J. Chromatogr, A687, pp. 121-132; Strazisar, B.R., Anderson, R.R., White, C.M., Degradation pathways for monoethanolamine in a CO 2 capture facility (2003) Energy & Fuels, 17, pp. 1034-1039; Strazisar, B.R., Anderson, R.R., White, C.M., (2010) Degradation of Monoethanolamine Used In Carbon Dioxide Capture From Flue Gas of a Coal-fired Electric Power Generating Station, , http://www.netl.doe.gov/publications/proceedings/01/carbon_seq/4b3.pdf; Supap, T., Idem, R., Tontiwachwuthikul, P., Saiwan, C., Analysis of monoethanolamine and its oxidative degradation products during CO 2 absorption from flue gases: A comparative study of GC-MS, HPLC-RID, and CE-DAD analytical techniques and possible optimum combinations (2006) Ind. Eng. Chem. Res, 45, pp. 2437-2451; Thitakamol, B., Veawab, A., Foaming behavior in CO 2 absorption process using aqueous solutions of single and blended alkanolamines (2008) Ind. Eng. Chem. Res, 47, pp. 216-225; Thitakamol, B., Veawab, A., Aroonwilas, A., Foaming in amine- based CO 2 capture process: Experiment, modeling and simulation (2009) Energy Procedia 1, (9), pp. 1381-1386. , http://www.google.com.my/images?hl=en&q=fouling%20effect&um=1&ie=UTF-8&source=og&sa=N&tab=wi; Weiland, R.H., Sivasubramanian, M.S., Dingman, J.C., (2003) Effective Amine Technology: Controlling Selectivity, Increasing Slip, and Reducing Sulfur, , http://www.ogtrt.com/files/file/publications/effective_amine_technology.pdf, The 53 rd Annual Laurence Reid Gas Condition Conference; Xia, J., Kamps, A.P.S., Maurer, G., Solubility of H 2S in (H 2O plus piperazine) and in (H 2O plus MDEA plus piperazine) (2003) Fluid Phase Equilib, 207 (1-2), pp. 23-34
| |
2010 |
S Shahla, N G Cheng, R Yusoff (2010) An Overview on Transesterification of Natural Oils and Fats Biotechnology and Bioprocess Engineering 15: 6. 891-904 Abstract: Transesterification of natural oils and fats has found various industrial applications, particularly in producing surfactants and biodiesel fuel Due to the biodegradability and environmental compatibility of the products, many studies have been conducted in this area An overview on transesterification of natural oils and fats is presented which includes the following topics Catalytic and non catalytic reactions and their optimum reaction conditions, types of catalysts and alcoholysis, reaction kinetics and mass transfer The reports and findings from these aspects collectively provide useful information and serve as good guidelines for transesterification research Notes: 701ZE Times Cited:3 Cited References Count:55
|
2009 |
N Kamarulzaman, R Yusoff, N Kamarudin, N H Shaari, N A A Aziz, M A Bustam, N Blagojevic, M Elcombe, M Blackford, M Avdeev, A K Arof (2009) Investigation of cell parameters, microstructures and electrochemical behaviour of LiMn(2)O(4) normal and nano powders Journal of Power Sources 188: 1. 274-280 Abstract: Nano materials are usually difficult to prepare. This work presents a simple way of preparing LiMn(2)O(4) nano powders using the high-energy ball milling method. This method has the advantage of producing pure, single-phase and crystalline nano powders. The milling method is carefully controlled to avoid unwanted chemical reactions that may change the stoichiometry of the material. Nano powders of between 30 and 50 nm are obtained. Structural studies of the nano powders, as well as the more-conventional micron-sized LiMn(2)O(4), are made using X-ray diffraction and neutron diffraction methods. Electrochemical evaluation of the materials is undertaken with a three-probe cyclic voltammetry technique and galvanostatic charge-discharge measurements. Structural studies reveal that not only are the crystallites of the nano powders much reduced in size from the normal powders, but their cell parameters are also smaller. The performance characteristics of the nano material show an improvement over that of the micron-sized material by about 17% in the 1st cycle and 70.6% in the 5th cycle, at which the capacity is 132 mAh g(-1). The normal material suffers from severe capacity fading but the nano material shows much improved capacity retention. (C) 2008 Elsevier B.V. All rights reserved. Notes: 421XK Times Cited:15 Cited References Count:19
|
2007 |
Abstract: The main objective of this work is to compare the difference between microwave heating and conventional thermal heating in fabricating carbon/epoxy composites. Two types of epoxy resin systems were used as matrices, LY5052-HY5052 and DGEBA-HY917-DY073. All composite samples were fabricated using resin transfer moulding (RTM) technique. The curing of the LY5052-HY5052-carbon and the DGEBA-HY917-DY073-carbon composite systems, were carried out at 100 ðC and 120 ðC, respectively. Microwave heating showed better temperature control than conventional heating, however, the heating rate of the microwave cured samples were slower than the conventionally cured samples. This was attributed to the lower power (250 W) used when heating with microwaves compared to 2000 W used in conventional heating. Study of thermal characteristics as curing progressed showed that the polymerisation reaction occurred at a faster rate during microwave curing than in conventional curing for both the DGEBA and the LY/HY5052 carbon composite systems. The actual cure cycle was reduced from 60 minutes to 40 minutes when using microwaves for curing DGEBAcarbon composites. As for LY/HY5052-carbon composites, the actual cure cycle was reduced from 3 hours to 40 minutes. Both conventional and microwave heating yielded similar glass transition temperatures (120 ðC for DGEBA systems and 130 ðC for LY/HY5052 systems). Microwave cured composites had higher void contents than conventionally cured composites (2.2-2.8% and 1.8-2.4% for DGEBA and LY/HY5052 microwave cured composites, respectively, compared to 0.2-0.4% for both DGEBA and LY/HY5052 thermally cured composites). C-scan traces showed that all composites, regardless of methods of curing, had minimal defects. Notes:
|
2001 |
M N Khan, R Yusoff (2001) Effects of inert organic and inorganic anions on the rates of intramolecular general base-catalyzed reactions of ionized phenyl salicylate (PS-) with piperidine in the presence of cationic micelles Journal of Physical Organic Chemistry 14: 2. 74-80 Abstract: Pseudo-first-order rate constants (k(obs)) for piperidinolysis of PS- follow the relationship k(obs) - k(0)= k(n)(obs) [Pip](T) ([Pip](T) = total concentration of Pip) at a constant [CTABr](T) (total concentration of cetyltrimethylammonium bromide), [MX] (inert salt concentration) and 35 degreesC. The values of k(n)(obs) at different [CTABr]T (ranging from 0.005 to 0.02 M) and [MX] follow the relationship k(n)(obs) = (k(w)(n) + k(w)(n) Psi [MX] + KnsM K-N K-S(0)[CTABr](T))/( 1 + Psi [MX] + K-S(0) [CTABr](T)), where k(w)(n) = k(n)(obs) at [CTABr](T) = [MX] = 0, Psi is an empirical parameter and K-S(0) is the CTABr micellar binding constant of PS- in the absence of MX. The magnitude of Psi is attributed to the ability of X- to expel PS- from micellar pseudophase to the aqueous pseudophase. The values of Psi vary in the order Psi (sodium cinnamate) >Psi (sodium 4-methoxybenzoate) >Psi (sodium 2-chlorobenzoate) >Psi (disodium isophthalate) >Psi (disodium phthalate) >Psi (sodium sulfate) >Psi (disodium fumarate). The values of k(M)(ns) K-N (k(M)(ns) = k(M)(n)/V-M, where k(M)(n) is the second-order rate constant for the reaction of Pip with PS- in the micellar pseudophase and V-M is the micellar molar volume in M-1 and K-N represents CTABr micellar binding constant of Pip) are not significantly affected by the presence of MX into the reaction mixtures. Copyright (C) 2000 John Wiley & Sons, Ltd. Notes: 400RT Times Cited:17 Cited References Count:34
|
|
L K Teh, R Ismail, R Yusoff, A Hussein, M N Isa, A R A Rahman (2001) Heterogeneity of the CYP2D6 gene among Malays in Malaysia Journal of Clinical Pharmacy and Therapeutics 26: 3. 205-211 Abstract: Background: Although Malays shared an origin with Chinese, their evolution saw substantial divergences. Phenotyping studies suggested that they differed in CYP2D6 polymorphism, with higher PM prevalence but lesser right-shift for debrisoquine MRs. Objective: To study the genotype distribution of CYP2D6 among the Malays in Malaysia. Method: We obtained DNA from 107 Malays and used PCR to determine common CYP2D6 alleles. Result: CYP2D6*1 occurred at a frequency of 36.0%, duplicated gene, 0.93%, CYP2D6*4, 2.8%, CYP2D6*5, 5.1%, CYP2D6*9, 3.3%, CYP2D6*10, 49.5% and CYP2D6*17, 0.5%. The findings of CYP2D6*17 and CYP2D6*9 were novel for Asia. The frequency for CYP2D6*10 was lower than in other Asian races. The most frequent genotypes were CYP2D6*1/*10 at 39.3%. Two subjects had genotypes that predicted PM phenotype, 35% showed genotypes that predicted intermediate metabolizers and one subject had a genotype that predicted ultra-rapid metabolism. Conclusion: The genetic polymorphism of CYP2D6 in Malays is different from Chinese and Far Eastern races. They may be intermediate between East Asians and Caucasians in CYP2D6 activity. Further study in relation to the evolution of races and disease prevalence may help to identify the contributions of the polymorphism in alleged susceptibility to diseases apart from delineating its contributions to ethnic differences in the pharmacology of CYP2D6 drugs. Notes: 446CT Times Cited:13 Cited References Count:29
| |
Selected :
Delete selected items
