• Title/Summary/Keyword: esters

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Kinetics and Mechanism of the Hydrolysis of N-Arylsulfonylbenzimidothiophenyl ester (N-Arylsulfonylbenzimidothiophenyl Ester 유도체의 가수분해에 대한 반응속도론적 연구)

  • Tae-Seong Huh;Tae-Rin Kim
    • Journal of the Korean Chemical Society
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    • v.20 no.1
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    • pp.73-86
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    • 1976

  • Four unreported derivatives of N-arylsulfonylbenzamide and six derivatives of N-arylsulfonylbenzimidothiophenyl ester were prepared. These were; p-methyl-N-(arylsulfonyl)benzamide, m-methyl-N-(arylsulfonyl)benzamide, m-nitro-N-(arylsulfonyl)benzamide, p-methoxy-N-(arylsulfonyl)benzamide, p-methyl-N-(arylsulfonyl)benzimidothiophenyl esters, p-chloro-N-(arylsulfonyl)benzimidothiophenyl ester, m-methyl-N-(arylsulfonyl)benzimidothiophenyl ester, p-nitro-N-(arylsulfonyl)benzimidothiophenyl ester, m-nitro-(arylsulfonyl)benzimidothiophenyl ester and p-methoxy-N-(arylsulfonyl)benzimidothiophenyl ester. The rate constants of the hydrolysis of N-arylsulfonylbenzimidothiophenyl esters were determined by ultraviolet spectrophotometry at various pH and rate equations which can be applied over a wide pH range were obtained. From the rate equation and substituent effects, one can conclude that above pH 11, the hydrolysis of N-arylsulfonylbenzimidothiophenyl esters are initiated by the attack of hydroxide ion, however, below pH 9, started by the addition of a water molecule on the azomethine group. At pH 9∼11, the competitive reaction between a water molecule and hydroxide ion is anticipated to occur.

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Improvement of Low Temperature Property of Biodiesel from Palm Oil and Beef Tallow Via Urea Complexation (요소 착물형성에 의한 포화지방산 고함유 팜유 및 우지 유래 바이오디젤의 저온유동성 개선효과 연구)

  • Lee, Yong-Hwa;Shin, Jung-Ah;Zhang, Hua;Lee, Ki-Teak;Kim, Kwang-Soo;Jang, Young-Seok;Park, Kwang-Geun
    • New & Renewable Energy
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    • v.8 no.4
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    • pp.38-43
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    • 2012

  • Biodiesel is non-petroleum based fuel produced from vegetable oils or animal fats through transesterification. The compositions of saturated and unsaturated fatty acids in the feedstocks are important factors for biodiesel quality in terms of low-temperature fluidity and oxidative stability. The goal of this study is to improve the cold flow property of biodiesel from vegetable and animal origin containing highly saturated methyl esters (approx. 50%). In this purpose poly-saturated methyl esters in palm and tallow biodiesel were removed via urea-based fractionation and then the recovered fractions (enriched unsaturated fatty acid methyl esters) were supplemented with cold flow improvers. The highest concentration of unsaturated fatty acid methyl esters (93.8%) was obtained using a urea/fatty acid ratio of 3:1 at the crystallization temperature of $0^{\circ}C$ for 17 hours in incubation, with recovery of 71% and the addition of cold flow improver (Flozol$^{(R)}$ 515, 3,000 ppm) to the enriched poly-unsaturated fatty acid methyl esters reduced the CFPP(cold filter plugging point) of palm biodiesel from $12^{\circ}C$ to $-42^{\circ}C$. In tallow biodiesel both the enrichment of unsaturated fatty acid methyl esters (93.71%) and the addition of cold flow improver (Infineum R408, 3,000ppm) reduced the CFPP from $10^{\circ}C$ to $-32^{\circ}C$.

  • https://doi.org/10.7849/ksnre.2012.8.4.038 인용 PDF KSCI

Synthesis and Anti-corrosion Properties of Succinic Acid Alkyl Half-Ester Derivatives (숙신산 알킬 하프-에스테르 유도체의 합성 및 해수에 대한 방청성능)

  • Baek, Seung-Yeob;Kim, Young-Wun;Chung, Keun-Wo;Yoo, Seung-Hyun
    • Applied Chemistry for Engineering
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    • v.22 no.4
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    • pp.367-375
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    • 2011

  • Succinic acid ester derivatives have been used as additives for the base oil of metal working fluids and pressure working oils. In this paper, a series of succinic acid alkyl half-esters were synthesized with over 97% yields by ring-opening reaction of succinic anhydride and fatty alcohol and were soluble in 100 N base oil within 1 wt% concentration. The structures and purities of ester derivatives were confirmed by $^1H-NMR$ and FT-IR spectrum and GC analysis. Anti-corrosion properties of the esters in sea water were evaluated through ASTM D665 method and weight loss method and compared to that of succinic alkyl esters without carboxylic acid group in the molecule. As the results, anti-corrosion properties of succinic acid alkyl half-esters with carboxylic acid group were better than those of succinic acid alkyl esters without carboxylic acid group. And, Anti-corrosion properties of the esters with a shorter alkyl chain of high concentration showed better performance than those with longer alkyl chain of low concentration. Inhibition efficiency % (IE%) of the esters was over 95% in the concentration of 80 ppm and corrosion rate (CR) was below 0.3 mm/year at the same concentration. Thus, the corrosion properties of succinic acid alkyl half-esters result from the carboxylic acid groups in molecules.

  • https://doi.org/10.14478/ace.2011.22.4.367 인용 PDF KSCI