925-93-9Relevant academic research and scientific papers
An Improved Procedure for the Preparation of Very Pure Ethanol-OD
Pesendorfer, Johann,Vierhapper, Friedrich W.
, p. 877 - 878 (1985)
Changed molar ratio of starting materials and prolonged reaction times in the deuterolysis of tetraethylorthosilicate gave yields of pure (>99.5percent) ethanol-OD (relative to starting D2O) nearly twice of that of a literature procedure. - Keywords: Deuterolysis; Ethanol-OD; Methanol-OD; Tetraethylorthosilicate
Aqueous phase hydrodeoxygenation of polyols over Pd/WO3-ZrO2: Role of Pd-WO3 interaction and hydrodeoxygenation pathway
Liu, Changjun,Sun, Junming,Brown, Heather M.,Marin-Flores, Oscar G.,Bays, J. Timothy,Karim, Ayman M.,Wang, Yong
, p. 103 - 109 (2016/05/11)
Aqueous phase processing of biomass derived sugar alcohols is one of the promising routes to convert biomass into fuels and chemicals. Bifunctional catalysts are critical in the aqueous phase hydrodeoxygenation of sugar alcohol. Understanding the interaction between metal and acidic metal oxides as well as the hydrodeoxygenation pathways will help develop more efficient bifunctional catalysts. Here, tungstated zirconia supported palladium catalysts were prepared and further characterized using nitrogen sorption, X-ray diffraction, FT-IR analysis of adsorbed pyridine, CO chemisorption and diffuse reflectance UV-vis. Strong interaction between palladium and WO3 in addition to a synergetic effect of the acidic and metallic sites were found to promote the aqueous phase hydrodeoxygenation of ethylene glycol. H-D exchange experiments using 13C{1H} NMR spectroscopy confirmed that the aqueous phase hydrodeoxygenation follows a dehydration-hydrogenation pathway. The hydrogenation of the dehydration products shifts the dehydration-hydration equilibrium toward the dehydration pathway and leads to highly selective C-O cleavage.
Isotope Effects in the Solvolysis of Sterically Hindered Arenesulfonyl Chlorides
Iazykov, Mykyta,Canle L., Moisés,Santaballa, J. Arturo,Rublova, Ludmila
, p. 744 - 750 (2015/10/06)
Solvent isotope effects in the ethanolysis of sterically hindered arenesulfonyl chlorides ruled out a proton transfer in the rate-determining step and agreed with a SN2 mechanism involving at least a second solvent molecule in the transition state (TS). The lack of a secondary kinetic isotope effect in the o-alkyl groups allows us to disregard the possible contribution of σ-π hyperconjugation. The measured activation parameters are consistent with a SN2 mechanism involving the participation of solvent molecules in the TS, possibly forming a cyclic TS through a chain of solvent molecules.
Synthesis, reactivity and catalytic properties of the allenylidene [Ru(C=C=CPh2)Cp(PTA)(PPh3)](CF3SO3) (PTA = 1,3,5-triaza-7-phosphaadamantane)
Serrano-Ruiz, Manuel,Lidrissi, Chaker,Ma?as, Sonia,Peruzzini, Maurizio,Romerosa, Antonio
, p. 654 - 661 (2014/03/21)
The reactivity of [RuCpCl(PTA)(PPh3)] with HC≡CPh and HC≡CC(OH)PPh2 has been studied. The reaction with the phenylacetylene did not provide the desired vinylidene ruthenium complex but as a collateral result the complex [RuCp(DMSO-κS)(PTA)(PPh 3)](CF3SO3) (1) was obtained by reaction of [RuCpCl(PTA)(PPh3)] with Ag(CF3SO3) in DMSO. Reaction of [RuCpCl(PTA)(PPh3)] with HC≡CC(OH)PPh2 provided the Ruthenium(II) diphenyl-allenylidene complex [Ru(C=C=CPh 2)Cp(PTA)(PPh3)](CF3SO3) (2) that was characterized by NMR, IR spectroscopy and elemental analysis. The chemistry of the new diphenyl-allenylidene ruthenium complex has been studied towards a variety of small molecules such as water, O2, n-propylamine, cyclohexylamine and ethanethiol. From the reaction of 2 with the amines and thiol, two isomers are obtained respectively but only one of them could be isolated and characterized. The allenylidene complex was found to be a useful catalyst for the trans-etherification of 1,4-butanedioldivinyl-ether, ethoxyethene and 1-methoxycyclohexa-1,3-diene
On the solvolysis kinetics of amidoesters derived from β-aminoalcohols
Hankins, Jamilah N.,Gouws, Michele,Mahajer, Amir,Kim, Ethan S.,Gwaltney, Kevin P.,Haseltine, John
experimental part, p. 2450 - 2453 (2012/06/01)
To better understand reactivity in such systems, fifteen amidoesters derived from β-aminoalcohols were solvolyzed at the ester group in mildly basic methanol-d4. All trials showed pseudo-first-order kinetics by 1H NMR. The rate constants are about 2 to 140-fold larger than those found with simple alkyl esters. The least bulky N-acyl groups generally sponsor the largest rate constants, and strongly so in two cases, but apparently not as a result of lesser steric crowding between the amide and ester groups. Rate constants are also greater for those amidoesters favoring an anti conformation at the amide linkage.
Structure dependence in the solvolysis kinetics of amino acid esters
Haseltine, John,Runyon, Jason W.
scheme or table, p. 3280 - 3283 (2010/07/18)
To better understand acyl transfer reactions of oligopeptides, seventeen N-acyl amino acid esters were solvolyzed in mildly basic methanol-d4. All show pseudo-first-order kinetics by 1H NMR. The rate constant varies up to 400-fold with the identity of the amino acid and up to 6200-fold with the identity of the N-acyl group. The impact of the N-acyl group on the rate constant is discussed in terms of crowding, amide conformation, and amide C{double bond, long}O bond character.
Alkyl radical generation in water under ambient conditions - A new look at the Guareschi reaction of 1897
Nguyen, Bao,Chernous, Katya,Endlar, Daniel,Odell, Barbara,Piacenti, Michela,Brown, John M.,Dorofeev, Alexander S.,Burasov, Alexander V.
, p. 7655 - 7658 (2008/09/18)
(Chemical Equation Presented) Chemical and biochemical significance of a long-forgotten 19th century observation: The hydrocarbon production from quaternary glutarimides on neutralization in water is the consequence of formation of alkyl radicals, which means that it is possible to generate alkyl radicals under very mild conditions. Oxygen trapping competes with hydrogen abstraction (see scheme).
Catalysis of transesterification reactions by lanthanides - Unprecedented acceleration of methanolysis of aryl and alkyl esters promoted by La(OTf)3 at neutral sspH and ambient temperatures
Neverov, Alexei A.,McDonald, Todd,Gibson, Graham,Brown
, p. 1704 - 1710 (2007/10/03)
La3+ catalysis of the methanolysis of the esters p-nitrophenyl, 2,4-dinitrophenyl, and phenyl acetate (1-3), phenyl benzoate (4), and ethyl, i-propyl, cyclohexyl, and tert-butyl acetate (5, 6a, 6b, 7) was studied at 25°C as a function of sspH and [La(OTf)3]. The active form of the catalyst is attributed to a dimethoxy-bridged dimer of stoichiometry (La3+)2(-OCH3)2, having maximum activity atsspH 8 to 9. For preparative reactions, the active catalyst can be made in situ simply by adding 0.01 equiv of La(OTf)3, and 0.01 equiv of NaOCH3 to a methanol solution containing the ester (1 M). Strong catalysis of methanolysis of both aryl and alkyl esters was observed, although tert-butyl acetate was inert. At sspH 8.5, where the catalyst is maximally active, the transesterification reactions are accelerated by 40 000-fold to 18 000 000-fold in the presence of as little as 5 mM catalyst relative to the background reaction depending on the ester structure. A mechanism for catalysis of transesterification is presented wherein the reactive species is generated by breaking a single La-OCH3 bond of the dimethoxy-bridged dimer to reveal a nucleophilic metal-bound methoxide - Lewis acid La3+ electrophilic pair.
Analysis of the Mechanism of Photolysis of Methanol-d4 Solutions of Acetylpropionyl Peroxide With the Use of Chemically Induced Dynamic Nuclear Polarization
Skakovskii, E. D.,Stankevich, A. I.,Lamotkin, S. A.,Tychinskaya, L. Yu.,Avrinskii, G. S.,Rykov, S. V.
, p. 770 - 777 (2007/10/03)
On the basis of the effects of chemically induced dynamic nuclear polarization of 1H and 13C and the yields of reaction products, the photolysis of methanol-d4 solutions of acetylpropionyl peroxide is investigated within the. temperature interval 193-333
