지구 온난화와 같은 환경 문제가 대두되고 화석 연료에 대한 의존도가 높아짐에 따라 탄소 중립 개념에 대한 관심이 높아졌다. 특히, 전세계적으로 폐기물의 에너지화에 대한 연구가 활발히 진행되고 있다. 혐기성 소화는 유기성 폐기물로부터 바이오가스를 생성하는 에너지 회수의 한 방법으로써 전 세계적으로 많이 사용되는 기술이며 혐기성 소화의 효율 증대와 관련된 연구 또한 지속되고 있다. 혐기성 소화의 효율 극대화와 안정적인 운영을 위해서는 운영 조건을 최적화하고 최적화된 운영 조건을 모니터링 및 관리하는 것이 매우 중요하다. 혐기성 소화 운영에 있어 메탄가스량, 온도 등과 같은 여러 인자들 중, 휘발성 유기산의 농도 변화를 모니터링하는 것은 단시간에 급작스러운 반응조 내 변화를 확인하는 데에 매우 효과적인 인자 중 하나라는 것이 많은 연구를 통해 밝혀졌다. 기존 휘발성 유기산 농도 측정법에는 적정법, GC분석법 등이 있으며, 이들 측정법들은 분석 시간이 오래걸리고 측정 결과가 분석 조건에 민감하기 때문에 새로운 측정법의 개발이 요구되는 실정이다. 본 연구에서는 이러한 단점을 보완하며 신뢰성이 확보된 결과를 측정할 수 있는 다공성 물질 이용 촉매모사반응을 적용하였다. 본 연구에서 다룬 휘발성 유기산 측정 방법은 다공성 물질을 이용하여 열적 처리를 통한 휘발성 유기산의 에스터화반응을 이용한 방법으로서, 별도의 용매 추출 없이 바로 물 속의 휘발성 유기산의 농도를 측정할 수 있으며 높은 정확성과 재현성을 가진다. 본 연구에서는 휘발성 유기산 농도 측정을 위해 촉매모사반응의 메탄올과 샘플의 비율, 샘플 농도, 반응 온도 등 주요 인자들의 최적화를 진행하였다. 또한, 기존의 휘발성 유기산 농도 측정법 중 하나인 분광광도법과 측정 결과를 비교하였다.

Subcritical hydrolysis followed by methyl estrification was used to produce bio-diesel from low valued waste cooking oil at mild reaction conditions in this study. More than 90% fatty acid methyl esther (FAME) conversion was achieved by subcritical hydrolysis without using catalysts at 275℃ for 45 minutes. The highest conversion to linoleic acid (C18:2) was obtained at this condition. The higher content of free fatty acid (FFA) in waste cooking oil resulted in higher conversion to FAME. It was also observed more prominent at high temperature due to auto catalytic behavior of FFA. FAME yield found about 92% without using catalyst; whereas 98% yield was obtained using 80% TiO2 loading S-TiO2/MCM-41 catalyst at 220℃ and 20 minutes. The amount of FAME increased may be due to trans-esterification of un-reacted TG, DG, and MG with methanol remained during the hydrolysis stage. The higher FAME conversion means the better quality bio-diesel.

Camellia oil과 palmitic, 그리고 stearic ethyl ester를 기질로 하고 Lipozyme TLIM을 촉매로 이용하여 interesterification을 통한 POS를 많이 함유한 반응물을 합성하고자 하였다. 반응 조건(반응효소비율, 반응시간, 기질의 비율)을 독립변수로 하여 중심 합성 계획에 의한 반응 표면 분석을 통하여 POS의 함량은 높이고, sn-2 position의 acyl migration을 낮추어 합성하는

이 실험은 녹차추출물이 흰쥐 소장mucosa에서 -oleic acid의 에스테르화 과정에 어떤 영향을 미치는지를 조사하기 위해서 설계되었다 먼저, olive oil을 구강으로 강제 투여했을 때, 1시간 그리고 5시간 후에, 녹차 성분의 변수에 의해서 소장 mucosa 내에 축적된 중성지방이 얼마나 감소하는지를 조사하였다. 그리고 소장세포 내에서 녹차 성분에 의해서 각종 지방으로 -oleic acid의 분배비율이 영향을 받는지 조사하였다. 이 실험

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 65oC, 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.

Esterification of soybean oil with methanol was investigated. First of all, liquid-liquid equilibriums for systems of soybean oil and methanol were measured at temperatures ranging from 40 to 65oC. Profiles of conversion of soybean oil with time were determined from the glycerine content in reaction mixtures for the different kinds of catalysts, such as NaOH, CaO, Ca(OH)2, MgO, Mg(OH)2, and Ba(OH)2. The effects of dose of catalyst, cosolvent and reaction temperature on final conversion were examined. Esterification of waste vegetable oil with methanol was investigated and compared to the case of soybean oil. Solubility of methanol in soybean oil was substantially greater than that of soybean oil in methanol. When the esterification reaction of soybean oil was catalyzed by solid catalyst, final conversion was strongly dependent on the alkalinity of the solid catalyst, and increased with the alkalinity of the metal. Hydroxides from the alkali metals were more effective than oxides. When Ca(OH)2 was used for the esterification catalyst, maximum value of final conversion was measured at dose of 4%. When CHCl3 as a cosolvent, was added into the reaction mixture of soybean oil which catalyzed by Ba(OH)2, maximum value of final conversion was appeared at dose of 3%. When waste vegetable oil was catalyzed by NaOH and solid catalysts, high final conversion, over 90%, and fast reaction rate were obtained.