http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Alkylation of anthracene to 2-isopropylanthracene catalyzed by Lewis acid ionic liquids
Min Chen,Ying Luo,Guofang Li,Minqiang He,Jimin Xie,Huamin Li,Xinhua Yuan 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.6
Alkylation of anthracene with 2-chloropropane to 2-isopropylanthracene catalyzed by various Lewis acidic ionic liquids (ILs), such as [Emim]Cl-AlCl3, [Emim]Cl-FeCl3, [Emim]Cl-ZnCl2, [Bmim]Cl-AlCl3, and [Omim]Cl-AlCl3 ([Emim]+=1-ethyl-3-methylimidazolium cation, [Bmim]+=1-butyl-3-methylimidazolium cation, [Omim]+=1-octyl-3- methylimidazolium cation,), was investigated. [Emim]C1-A1C13 ionic liquid was found to be the most active catalyst in the alkylation. The yield of 2-isopropylanthracene was up to 74.5% and the selectivity of 2-isopropylanthracene was up to 82.9%. The [Emim]C1-A1C13 ionic liquid catalyst showed good catalytic activity after running for 6 times. Ease of product separation and the recycling performance of the ionic liquid catalyst is expected to contribute to the development of clean and environmentally friendly strategy for the synthesis of 2-isopropylanthracene.
Kim, Tae-Jin,Kim, Sung-Kwan,Kim, Beom-Jun,Son, Ho-Jin,Hahn, Jong Sok,Cheong, Minserk,Mitoraj, Mariusz,Srebro, Monika,Pię,koś,, Łukasz,Michalak, Artur,Kang, Sang Ook WILEY-VCH Verlag 2010 Chemistry Vol.16 No.19
<P>A series of mono-, bis-, and tris(phenoxy)–titanium(IV) chlorides of the type [Cp*Ti(2-R&n.bond;PhO)<SUB>n</SUB>Cl<SUB>3−n</SUB>] (n=1–3; Cp*=pentamethylcyclopentadienyl) was prepared, in which R=Me, iPr, tBu, and Ph. The formation of each mono-, bis-, and tris(2-alkyl-/arylphenoxy) series was authenticated by structural studies on representative examples of the phenyl series including [Cp*Ti(2-Ph&n.bond;PhO)Cl<SUB>2</SUB>] (1 PhCl2), [Cp*Ti(2-Ph&n.bond;PhO)<SUB>2</SUB>Cl] (2 PhCl), and [Cp*Ti(2-Ph&n.bond;PhO)<SUB>3</SUB>] (3 Ph). The metal-coordination geometry of each compound is best described as pseudotetrahedral with the Cp* ring and the 2-Ph&n.bond;PhO and chloride ligands occupying three leg positions in a piano-stool geometry. The mean Ti&n.bond;O distances, observed with an increasing number of 2-Ph&n.bond;PhO groups, are 1.784(3), 1.802(4), and 1.799(3) Å for 1 PhCl2, 2 PhCl, and 3 Ph, respectively. All four alkyl/aryl series with Me, iPr, tBu, and Ph substituents were tested for ethylene homopolymerization after activation with Ph<SUB>3</SUB>C<SUP>+</SUP>[B(C<SUB>6</SUB>F<SUB>5</SUB>)<SUB>4</SUB>]<SUP>−</SUP> and modified methyaluminoxane (7% aluminum in isopar E; mMAO-7) at 140 °C. The phenyl series showed much higher catalytic activity, which ranged from 43.2 and 65.4 kg (mmol of Ti⋅h)<SUP>−1</SUP>, than the Me, iPr, and tBu series (19.2 and 36.6 kg (mmol of Ti⋅h)<SUP>−1</SUP>). Among the phenyl series, the bis(phenoxide) complex of 2 PhCl showed the highest activity of 65.4 kg (mmol of Ti⋅h)<SUP>−1</SUP>. Therefore, the catalyst precursors of the phenyl series were examined by treating them with a variety of alkylating reagents, such as trimethylaluminum (TMA), triisobutylaluminum (TIBA), and methylaluminoxane (MAO). In all cases, 2 PhCl produced the most catalytically active alkylated species, [Cp*Ti(2-Ph&n.bond;PhO)MeCl]. This enhancement was further supported by DFT calculations based on the simplified model with TMA.</P> <B>Graphic Abstract</B> <P>Hard-boiled evidence: Complexes of the type [Cp*Ti(2-R&n.bond;PhO)<SUB>n</SUB>Cl<SUB>3−n</SUB>] (n=1–3) clearly enhance the activity of the polymerization of ethylene (>20 %) as a result of the inclusion of the second 2-phenylphenoxy ligand. A series of alkylations on other such complexes and variation in the Al/Ti ratio reveal that the concentration of [Cp*Ti(2-Ph&n.bond;PhO)MeCl] (Cp*=pentamethylcyclopentadienyl; see picture) is responsible for the activity, which is further confirmed by DFT calculations. <img src='wiley_img_2010/09476539-2010-16-19-CHEM201000191-content.gif' alt='wiley_img_2010/09476539-2010-16-19-CHEM201000191-content'> </P>
Weiming Yan,Yan Sun,Yutong Wang,Wangjiao Liang,Yuxin Xia,Weihua Yan,Meizhu Chen,Tao Chen,Dongliang Li 한국통합생물학회 2023 Animal cells and systems Vol.27 No.1
Upregulation of Sirtuin Type 1 (SIRT1), a nicotinamide adeninedinucleotide (NAD+)-dependentdeacetylase, has been proved to protect against ample ocular diseases, while its effect onretinitis pigmentosa (RP) has not been illustrated. The study was aimed to explore the impactsof resveratrol (RSV), a SIRT1 activator, on the photoreceptor degeneration in a rat model of RPinduced by N-methyl-N-nitrosourea (MNU), an alkylation. The rats were induced RP phenotypesvia the intraperitoneal injection of MNU. The electroretinogram was conducted and revealedthat RSV could not prevent the decline of retinal function in the RP rats. The optical coherencetomography (OCT) and the retinal histological examination were performed and showed thatthe reduced thickness of the outer nuclear layer (ONL) was not preserved by RSV intervention. The immunostaining technique was applied. Afther the MNU administration, the number of theapoptotic photoreceptors in the ONL throughout the retinasand the number of microglia cellspresent among the outer part throughout the retinas were not significantly reduced by RSV. Western blotting was also performed. The data showed that the level of SIRT1 protein wasdecreased after MNU administration, while RSV was not able to obviously alleviate thedownregulation. Our data together indicated that RSV was not able to rescue thephotoreceptor degeneration in the MNU-induced RP rats, which might be due to the MNUinducedconsumption of the NAD+.
A Theoretical Study on the Alkylation of the Ambident Enolate from a Methyl Glycinate Schiff Base
남기평,Seungmin Lee 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.8
The alkylation of the ambident enolates of a methyl glycinate Schiff base with ethyl chloride was studied at B3LYP and MP2 levels with 6-31+G* basis set. The free (E)-enolates and (Z)-enolate are similar in energy and geometry. The transition states for the alkylation of the free (E)/(Z)-enolate with ethyl chloride have similar energy barriers of ~13 kcal/mol. However, with a lithium ion, the (E)-enolate behaves as an ambident enolate and makes a cyclic lithium-complex in bidentate pattern which is more stable by 11-23 kcal/mol than the (Z)- enolate-lithium complexes. And the TS for the alkylation of (E)-enolate-lithium complex coordinated with one methyl ether is lower in energy than those from (Z)-enolate-lithium complexes by 4.3-7.3 kcal/mol. Further solvation model (SCRF-CPCM) and reaction coordinate (IRC) were studied. This theoretical study suggests that the alkylation of ambident enolates proceeds with stable cyclic bidentate complexes in the presence of metal ion and solvent.
A Theoretical Study on the Alkylation of the Ambident Enolate from a Methyl Glycinate Schiff Base
Nahm, Kee-Pyung,Lee, Seung-Min Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.8
The alkylation of the ambident enolates of a methyl glycinate Schiff base with ethyl chloride was studied at B3LYP and MP2 levels with $6-31+G^*$ basis set. The free (E)-enolates and (Z)-enolate are similar in energy and geometry. The transition states for the alkylation of the free (E)/(Z)-enolate with ethyl chloride have similar energy barriers of ~13 kcal/mol. However, with a lithium ion, the (E)-enolate behaves as an ambident enolate and makes a cyclic lithium-complex in bidentate pattern which is more stable by 11-23 kcal/mol than the (Z)-enolate-lithium complexes. And the TS for the alkylation of (E)-enolate-lithium complex coordinated with one methyl ether is lower in energy than those from (Z)-enolate-lithium complexes by 4.3-7.3 kcal/mol. Further solvation model (SCRF-CPCM) and reaction coordinate (IRC) were studied. This theoretical study suggests that the alkylation of ambident enolates proceeds with stable cyclic bidentate complexes in the presence of metal ion and solvent.
Effect of CO2 in the toluene side-chain alkylation with methanol
서동우,박상언,( Nanzhe Jiang ) 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0
By Far economic manufacture of styrene remains a challenge because the current industrial process suffers from drawbacks such as multi steps, high energy consumption and environmental impact. As an alternative method for the production of styrene from cheap raw materials like toluene and methanol was proposed by several groups including our group. Zeolites are widely used in the side chain alkylation of toluene using methanol because of their unique properties like uniform pore size, high thermal stability and tunable basicity by ion exchange or impregnation with (K, Na, Cs and Ba) as the reaction proceeds via base catalysis. In this work, we studied the effect of temperature with ion-exchanged zeolite X under CO2 flow in the side-chain alkylation of toluene with methanol. The effect of CO2 on the activity and selectivity in the side-chain alkylation of toluene with methanol will be discussed.
( Yeon Ju Lee ),( Jeyoung Seo ),( Dong Guk Kim ),( Hyeung Geun Park ),( Byeong Seon Jeong ) 영남대학교 약품개발연구소 2013 영남대학교 약품개발연구소 연구업적집 Vol.23 No.0
Rapid and efficient C(4)-alkylation of 4-alkyloxazol-5(4H)-ones has been achieved by the utilization of BEMP as base 4, 4-Dialkyloxazol-5(4H)-ones, which can easily be hydrolyzed into free α, α-dialkyl- α-amino acids, were obtained in high yields (up to 99%) within a few minutes (1-18 min). BEMP, a sterically hindered strong base with low nucleophilicity facilitated the desired reaction, while decreasing the rate of side reactions such as o-alkylation, C(2)-alkylation and the breakage of oxazolone.
합성 윤활유 제조를 위한 퍼옥사이드계 개시제를 이용한 이소파라핀의 단독 알킬레이션
카드카로산(Roshan Khadka),이상우(Sang Woo Yee),김용운(Yong Woon Kim),유재욱(Jae Wook Yun),임진형(Jin Heong Yim) 한국고분자학회 2014 폴리머 Vol.38 No.4
폴리알파올레핀은 낮은 유동점, 높은 점도지수와 같은 물리화학적 특성이 기존의 광유보다 우수한 합성윤활유이다. 본 논문은 퍼옥사이드계 개시제를 이용하여 올레핀을 사용하지 않고 이소파라핀 분자간의 알킬레이션 반응을 통한 합성 윤활유 제조에 관한 새로운 경로를 제시한다. 평균 탄소수사 i-c16, i-c18, 그리고, i-c23인 세가지 장쇄이소파라핀의 알킬레이션과 i-c18과 2-pentene의 알킬레이션을 di-tert butyl peroxide 라디칼 개시제를 사용하여 여러가지 반응조건에서 수행하여 단독 알킬레이션 반응 경로를 확인하였다. 세가지 유분으로 제조된 알킬레이트를 합성윤활유로의 적용 가능성을 알아보기 위하여 동점도. 점도지수, 및 유동점을 조사하였다. i-c16및 i-c18 유분으로 제조된 단독 알킬레이트는 극초고점도지수(>140)와 낮은 유동점(<-30℃)을 보였다. Polyalphaolefin (PAO) is a synthetic that is superior to mineral-based lubricants in terms of physical and chemical characteristics such as low pour point (PP), and high viscosity index (VI). This paper first reports a novel preparation route for a synthetic lubricant via alkylation of isoparaffins using a peroxide initiator without olefin. Alky-lation of three kinds of isoparaffins such as i-C16, i-C18, and i-C23 as well as alkylation of i-C18 with 2-pentene using di-tert butyl peroxide initiator were conducted under various conditions to confirm alkylation reaction from iso-paraffins themselves i.e; Single-molecule alkylation made from i-C16 and i-C18 showed ultra high VI(>140) and low PP (<-30℃).