• 제목/요약/키워드: Ethylation

검색결과 18건 처리시간 0.019초

Diffusion Controlled Alkylation of Aromatic Compounds in Cation-Exchanged ZSM-5 Zeolites

  • Chon, Hak-Ze;Lee, Kyung-Yul;Park, Dong-Ho;Ahn, Byoung-Joon
    • Bulletin of the Korean Chemical Society
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    • 제12권6호
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    • pp.625-628
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    • 1991
  • Using uniform flat plate-like samples of ZSM-5 zeolites, diffusion coefficients were measured volumetrically for the diffusion of xylene, ethyltoluene and diethylbenzene by direct measurement of sorption rate. Toluene disproportionation over H(100)-, K(72)-and Cs(82)-ZSM-5 at 773 K and toluene methylation, toluene ethylation and ethylbenzene ethylation over Cs(75)-ZSM-5 at 623 K were carried out. The selective formation of para xylene during the toluene disproportionation, presumably due to the increased tortuosity over Cs-ZSM-5, could be explained by smaller diffusion coefficient in Cs-ZSM-5 than in K-and H-ZSM-5. The para selectivity increased in the order; toluene methylation < toluene ethylation < ethylbenzene ethylation. As the chain length of the alkyl substituent in dialkylbenzenes is increased, the para selectivity of the products was improved. It may be attributed to the differences in the ratios of diffusion coefficient of para products to that of ortho ones. Diffusion coefficient of m-xylene was about 1 order of magnitude smaller than that of o-xylene.

기체크로마토그래프/질량분석기에 의한 물시료 중 Organotin의 추출 및 유도체 반응에 관한 연구 (The Extraction and Derivatization of Organotins in Water Sample by Gas Chromatograph/Mass Spectrometer)

  • 홍지은;이강진;표희수;박송자;이원
    • 분석과학
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    • 제13권5호
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    • pp.636-645
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    • 2000
  • 본 연구에서는 GC/MS를 이용하여 수질시료로부터 7종의 유기주석화합물을 분석하는 방법을 연구하였다. Hydrogenation과 ethylation의 반응시의 pH, 반응시간, 반응시약의 농도 등을 변화시켜 최적 반응조건을 조사하였다. n-Hexane을 용매로 사용한 액체-액체 추출 후 hydrogenation에 의한 유기주석염화물의 추출 회수율은 61-112% 범위로 나타났다. 물시료에서 ethylation한 후 n-hexane으로 추출한 경우의 추출 회수율이 74-113% 범위로 나타나 hydrogenation의 경우보다 높은 추출율을 보였다. 또한 ethylation후 styrene-divinylbenzene (SDB) 재질의 disk형의 고체상을 사용하고 추출 용매로 methylene chloride를 사용한 경우 61-97% 범위의 회수율을 나타냈다. Hydrogenation과 ethylation에 의한 검출한계는 각각 0.05-0.5 ng/ml와 0.02-0.05 ng/ml로 나타났다.

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Application of a Gas Chromatography/Mass Spectrometric Method for the Determination of Butyltin Compounds in Sediment

  • Won, Yong-Il;Jung, Pyong-Gil;Chung, Min-Young;Kim, Byung-Joo;Yim, Yong-Heon;So, Hun-Young;Kim, Yong-Seong
    • Bulletin of the Korean Chemical Society
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    • 제25권10호
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    • pp.1508-1512
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    • 2004
  • A gas chromatography/mass spectrometric (GC/MS) method has been developed for the determination of trace mono-n-butyltin (MBT), di-n-butyltin (DBT), and tri-n-butyltin (TBT) compounds in sediments. Samples were extracted by 10% acetic acid in methanol containing 0.03% tropolone and were then derivatized for GC/MS analysis. Ethylation by sodium tetraethylborate and phenylation by sodium tetraphenylborate were evaluated as a derivatization reaction of the organotins in sample extract. n-Hexane was added into reaction media in the beginning of the reaction for the continuous extraction of derivatized organotins. Ethylation requires less than 2 hours to get proper derivatization yields for MBT, DBT, and TBT altogether and produces relatively low amounts of side reaction products. Compared to ethylation, phenylation requires much longer time but provides relatively lower yield and produces considerable amounts of side reaction products. Therefore, the ethylation reaction was applied for the analysis of organotin compounds in sediment. An isotope dilution mass spectrometric (IDMS) method based on GC/MS has been applied to the accurate determination of DBT compounds in the sediments. The IDMS results from the analyses of sediment samples showed a reasonable repeatability and a good agreement with the values obtained by IDMS based on liquid chromatography/induced coupled plasma/mass spectrometry.

Shape-Selective Catalysis over Zeolite. An Attempt in the Alkylation of Biphenyl

  • Sugi, Yoshihiro;Komura, Kenichi;Kim, Jong Ho
    • 공업화학
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    • 제17권3호
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    • pp.235-242
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    • 2006
  • Liquid phase alkylation of biphenyl (BP) was studied over large pore zeolites. Selective formation of the least bulky products, 4,4'-diisopropylbiphenyl (4,4'-DIPB) occurred only in the isopropylation of BP over some large pore molecular sieves. H-mordenites (MOR) gave the highest selectivity among them. The dealumination of MOR enhanced catalytic activity and the selectivity of 4,4'-DIPB because of the decrease of coke-deposition. Non-selective catalysis occurs on external acid sites over MOR with the low $SiO_2/Al_2O_3$ ratio because severe coke-deposition deactivates the acid sites inside the pores by blocking pore openings. The selectivity of DIPB isomers was changed with reaction temperature. Selective formation of 4,4'-DIPB was observed at moderate temperatures such as $250^{\circ}C$, whereas the decrease of the selectivity of 4,4'-DIPB occurred at higher temperatures as $300^{\circ}C$. However, 4,4'-DIPB was almost exclusive isomer in the encapsulated DIPB isomers inside the pores even at high temperatures. These decreases of the selectivity of 4,4'-DIPB are due to the isomerization of 4,4'-DIPB on the external acid sites. Some 12-membered molecular sieves, such as SSZ-24, MAPO-5 (M:Mg, Zn, Si), SSZ-31, and ZSM-12, which have straight channels, gave 4,4'-DIPB with moderate to high selectivity; however; SSZ-55, SSZ-42, and MAPO-36 (M: Mg, Zn) gave lower selectivity because of cages in 12-membered one dimensional channels. Three dimensional H-Y and Beta zeolites also yield 4,4'-DIPB in low yield because of their wide circumstances for the isopropylation of BP. The increasing the size of alkylating agent enhanced the shape-selective alkylaiton even for the zeolites, such as UTD-1. The ethylation of BP to ethylbiphenyls (EBPs) and diethylbiphenyls (DEBPs) over MOR was non-selective. The ethylation of BP to EBPs was controlled kinetically. However, there was difference in reactivity of EBPs and DEBPs for their further ethylation. 4-EBP was ethylated preferentially among the isomers, although the formation of 4,4'-DEBP was less selective. The least bulky 4-EBP and 4,4'-DEBP have the highest reactivity among EBPs and DEBPs for the ethylation to polyethylbiphenyls (PEBPs). These results show that the environments of MOR pores are too loose for shape selective formation of the least bulky isomers, 4-EBP and 4,4'-DEBP in the ethylation of BP, and that MOR pores have enough space for the further ethylation of 4,4'-DEBP.

4-Aminosalicylic Acid 유도체의 합성연구(II) 2-Ethoxy-4-acetamidobenzamide의 합성 (Studies on 4-Aminosalicylic Acid Derivatives (II). Synthesis of 2-Ethoxy-4-acetamidobenzamide)

  • 이남순;유서홍
    • 약학회지
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    • 제19권2호
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    • pp.96-100
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    • 1975
  • 2-Ethoxy-4-acetamidobenzoate (III) was synthesized by ethylation of N-formyl compound obtained with formylation of methyl 4-aminosalicylate and 2-ethoxy-4-acetamidobenzamide (VIII) was synthesized by ethylation of 4-acetamidosalicylamide (VII) formed by reacting methyl 4-acetamido-2-acetoxy benzoate with concentrated ammonia water under pressure. 2-Ethoxy-4-acetamido benzamide (VIII) was also synthesized by acetylation of 2-ethoxy-4-aminobenzamide (VI) obtained by pressure eraction of methyl 2-ethoxy-4-formylamido-benzoate (I) with concentrated ammonia water.

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Fluoridemedium에서 HZSM-5 제올라이트를 이용한 알킬아로마틱의 선택적 알킬화 (Selective alkylation of alkylaromatics over HZSM-5 zeolite synthesised in fluoridemedium)

  • 푸시파라지 헤마라다;칸단 벤카타찰람;마니가니쉬;팽메이메이;이주보;장현태
    • 한국산학기술학회:학술대회논문집
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    • 한국산학기술학회 2011년도 춘계학술논문집 1부
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    • pp.323-326
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    • 2011
  • HZSM-5, synthesized in fluoride medium, showed high selectivity for the formation of 1,4-diethylbenzene (1,4-DEB) in the vapour phase ethylation of ethylbenzene (EB) with ethanol and hence becomes a convenient eco-friendly substitute for hazardous mineral acid catalysts. De-ethylation of EB to benzene was also minimized over this catalyst. As the medium pore size and presence of weak and medium acid sites might be the cause of such benefits, fluoride mediated synthesis of ZSM-5 is proven to be advantageous for para-selective alkylation of alkyl aromatics.

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$(\pm)$-2-[p-(1-Oxo-2-isoindolinyl)phenyl]butyric acid(인도부펜)의 합성 (Facile Synthesis of $(\pm)$-2-[p-(1-Oxo-2-isoindolinyl)phenyl]butyric acid (Indobufen))

  • 최홍대;강병원;마정주;윤호상
    • 약학회지
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    • 제35권5호
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    • pp.389-393
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    • 1991
  • A convenient method for the synthesis of indobufen, which is a potent antiinflammatory agent, was described. Ethyl 2-phenylbutyrate(4) was prepared by Friedel-Crafts reaction of benzene with ethyl $\alpha$-chloro-$\alpha$-(methylthio)acetate(l) followed by ethylation and desulfurization of the resultant ethyl 2-(methylthio)phenylacetate(2). Ethyl 2-(p-aminophenyl)butyrate(6) was prepared by nitration of (4) and successive reduction of ethyl 2-(p-nitrophenyl) butyrate(5). Indobufen was obtained by condensation reaction of (6) with phthalic anhydride followed by reduction and hydrolysis of the resultant ethyl 2-[p-(1, 3-dioxo-2-isoindolinyl)phenyl]butyrate(7).

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2-(4-비페닐일)부티르산의 합성 (Facile Synthesis of 2-(4-Biphenylyl)butyric Acid)

  • 최홍대;윤호상;강병원;손병화;정우진
    • 약학회지
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    • 제36권2호
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    • pp.137-139
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    • 1992
  • A new method for xenbucin, which is a antihypercholesteremic agent, is described. Friedel-Crafts reaction of biphenyl with ethyl ${\alpha}-chloro-{\alpha}-(methylthio)acetate(1)$ afforded ethyl 2-methylthio-2-(4-biphenylyl)acetate(2). Ethyl 2-(4-biphenylyl)butyrate(4) was obtained by ethylation of (2) with NaH and $C_2H_5I$, followed by desulfurization of the resultant ethyl 2-methylthio-2-(4-biphenylyl)butyrate(3) with zinc dust in acetic acid. Xenbucin was synthesized by hydrolysis of (4).

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