• Journal of Environmental Science International
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• v.17 no.2
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• pp.211-224
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• 2008

Characteristics of the esterification reaction between free fatty acid in rice bran oil and methanol was investigated in the presence of catalysts, such as PTS(p-toluene sulfonic acid), Amberlyst 15 dry and SCX(silica gel based strong cation exchange resin). While reaction temperature was kept constant at $65^{\circ}C$, initial feed content of free fatty acid was varied from 100% to 1% by addition of pure free fatty acid which was previously made from rice bran oil. Also, the effect of mole ratio of methanol to fatty acid on the final conversion was examined. When esterification of pure free fatty acid was catalyzed by several acids, final conversions were increased in order of Amberlyst 15 dry, SCX and PTS. Using PTS catalyst, initially the reaction proceeded in homogeneous 2nd oder reaction mechanism. However, phase of reaction mixture changed from homogeneous to heterogeneous along the reaction time and then reaction rate was retarded by mass transfer resistance of methanol. Final conversion of free fatty acid in reaction mixture was depended on initial feed content of free fatty acid, and had maximum value at 30% of initial feed free fatty acid content for all kinds of catalysts used. And the final conversion was increased with mole ratio of methanol by the improvement of reaction rate. When initial feed free fatty acid content below 10% and the reaction was catalyzed by PTS, concentration of free fatty acid in reaction mixture was increased in the middle of reaction time by hydrolysis of triglyceride in reaction mixture. Also, if silica gel was added into the reaction mixture which had initial feed free fatty acid content below 50%, final conversion was increased by the adsorption of moisture produced. The SCX catalyst made the esterification reaction of free fatty acid to progress like in case of PTS catalyst. However, when initial feed free fatty acid content below 10%, concentration of free fatty acid in. reaction mixture was decreased monotonically and not increased in the middle of reaction time on the contrary to the case of PTS. Thus, SCX catalyst accomplished more high value of final conversion than PTS catalyst for the initial feed fatty acid content range from 50% to 5% In case of initial feed free fatty acid content of 1% and mole ratio of methanol was 2, concentration of free fatty acid in reaction mixture increased over the initial feed free fatty acid content for all kind of catalysts used. Although SCX catalyst was added into reaction mixture which had 1% of initial feed fatty acid content, final conversion was hardly raised by mole ratio of methanol.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2963-2967
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• 2013

This paper describes a simple and efficient method involving domino Knovenegal/$6{\pi}$ electrocyclization for the preparation of a variety of 2H-pyrans using microwave irradiation under solvent- and catalyst-free conditions. This method offers the advantages of a green approach, high yields, and short reaction times. Sixteen compounds (9a-p) were obtained in good to excellent yields using the procedure.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4297-4303
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• 2011

Under solvent-free conditions, the synthesis of propargylic alcohols by direct addition of terminal alkynes to aldehydes promoted by ZnO as a novel, commercially, and cheap catalyst is described. Furthermore, the catalyst can be reused for several times without any significant loss of its catalytic activity.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1071-1076
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• 2009

N,N,N′,N′-tetramethylethylenediamine (TMEDA) acts as a simple, mild and efficient catalyst for the acylation of alcohols, phenols and thiols at room temperature under solvent-free condition. Acylation reaction with acetic anhydride and benzoic anhydride proceeds with good to excellent yield in the presence of TMEDA as the catalyst.

• Journal of the Korean Chemical Society
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• v.52 no.1
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• pp.52-56
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• 2008

facile and efficient method for the preparation of Z-aldoximes is improved by means of H3PMo12O40 catalyst in solvent-free media. The major advantages of this method are: operational simplicity, low catalyst loading, selectivity, mild reaction conditions, short reaction times and excellent yields. The recovered catalyst could be used in new attempts without any purification.

• Journal of the Korean Applied Science and Technology
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• v.25 no.3
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• pp.275-281
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• 2008

The esterification of free fatty acid in Jatropha oil added by propylene glycol using p-TSA catalyst was done, and then the transesterification of Jatropha oil added by 1.0vol% GMS as an emulsifier using TMAH, and mixed catalyst(60wt%-TMAH+ 40wt%-KOH) respectively was followed at $60^{\circ}C$. The esterification conversion at the 1:8 molar ratio of free fatty acid to methanol using 8.0wt% p-TSA was 94.7% within 60min. The overall conversion at the 1:8 molar ratio of Jatropha oil to methanol and $60^{\circ}C$ using mixed catalyst was 95.4%. The kinematic viscosity of Biodiesel using TMAH and mixed catalyst in 24h met the ASTM D-6751 above $30^{\circ}C$, and showed a little more than its criterion.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.633-637
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• 2011

Iron (III) phosphate was employed as an efficient catalyst for the chemo selective acetylation of alcohols and phenols under solvent free condition at room temperature and with high yields. Iron (III) phosphate is also a potential green catalyst due to solid intrinsically, reusable and with high catalytic activity.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4167-4170
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• 2011

An inexpensive and efficient catalyst system has been developed for the N-arylation of phenylurea including a variety of aryl halides. This simple protocol uses $Cu_2O$ as the catalyst, microwave assisted, solvent- and ligand-free, $K_3PO_4{\cdot}H_2O$ as the base.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.541-543
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• 2006

The feasibility of biodiesel production from soapstock by acid catalyst was tested. The water content of soapstock was more than 40%. Before the esterification of soapstock, the pre-treatment of soapstock was conducted adding potassium hydroxide and sulfuric acid. The pre-treated soapstock contained 99.6wt% of free fatty acid. When the free fatty acid was esterified with methanol, the fatty acid methyl ester content became 91.7wt% under the solid acid catalyst, Amberlyst-15. When this biodiesel was distilled the methyl ester content was 98.1wt% which satisfied the biodiesel Standard. Amberlyst-15 could be recovered easily because it was the soliid catalyst. When sulfuric acid was used as the acid catalyst, the fatty acid methyl ester content was 91.0wt%. From the results, it was possible to produce biodiesel efficiently from soapstock after pre-treatment. Because soapstock is very cheap, it will become good feedstock for biodiesel product ion.

• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.4001-4004
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• 2011

Various 5-substituted 1H-tetrazole derivatives were synthesized in a simple and environmentally benign method from the reaction of aryl and benzyl nitriles with sodium azide in solvent-free media using montmorillonite K-10 clay as solid recyclable heterogeneous acidic catalyst and microwave irradiation in good yields and short reaction times.