109-86-4Relevant articles and documents
Plastic crystalline lithium salt with solid-state ionic conductivity and high lithium transport number
Moriya, Makoto,Kato, Daiki,Sakamoto, Wataru,Yogo, Toshinobu
, p. 6311 - 6313 (2011)
Plastic crystallinity of lithium salt, [LiB(OCH2CH 2OCH3)4] (1), and its solid-state ionic conductivity are disclosed. The addition of small amounts of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) to borate 1 led to the drastic increase of the ionic conductivity and lithium transport number of the electrolyte.
Participation by Ether Oxygen (RO-3) in the Hydrolysis of Sulfonate Esters of 2-Methoxyethanol and 2-Methoxy-2-methyl-1-propanol. Implications Regarding the Nonlinear Ethanol-Trifluoroethanol Plot for Mustard Chlorohydrin
McManus, S. P.,Karman, R. M.,Sedaghat-Herati, R.,Neamati-Mazraeh, N.,Hovanes, B. A.,et al.
, p. 2518 - 2522 (1987)
The lack of scrambling with deuterium-labeled reactants, a nonlinear ethanol-trifluoroethanol plot, and rate acceleration by edded thiourea are used to show that sulfonate esters of methoxyethanol (MeOCH2CH2OH) undergo solvent-assisted displacement in a variety of solvents; neighboring group participation by ether oxygen (RO-3 participation) does not occur.This conclusion is in accord with predictions of rate based on the Taft treatment of substituent effects.On the other hand, the branched derivative MeOCMe2CH2OBs reacts with concerted RO-3 participation to give completely rearranged product.It solvolysis rate is insensitive to added thiourea, the Taft treatment predicts modest anchimeric assistance, and a linear ethanol-trifluoroethanol plot is observed.We discuss the implications of these results relative to the previously observed nonlinear plot for mustard chlorohydrin.
SN2 Displacement on 2-(Alkylthio)ethyl Derivatives
Herati-Sedaghat, M. R.,McManus, Samuel P.,Harris, J. Milton
, p. 2539 - 2543 (1988)
We have studied the reaction mechanism of various 2-(alkylthio)ethyl and 2-(arylthio)ethyl derivatives with strong nucleophiles in an attempt to overcome powerful neighboring sulfur participation and shift reaction to a direct displacement SN2 mechanism.The 2,4-dinitrophenolate derivative of specifically deuteriated 2-(methylthio)ethanol reacts by an aromatic substitution mechanism (SNAr) when exposed to amines in aprotoc solvents.Use of sulfonate esters avoids competition from the SNAr mechanism.The rate of reaction of these esters in dimethyl sulfoxide (DMSO) or acetonitrile is independent of concentration of added methylamine, thiourea, urea, or iodide, thus indicating continued SN1 reaction with neighboring sulfur participation.Asd would be expected on this basis, but in contrast to previous mechanistic suggestions, the product for reaction with iodide in acetone shows complete scrambling of methylene groups.In contrast, reaction with thiophenolate ions in DMSO proceeds by direct nucleophilic displacement (an SN2 mechanism), as shown by second-order kinetics and unrearranged product.This is the first demonstration of SN2 displacement on a 2-(alkylthio)ethyl or 2-(arylthio)ethyl derivative.
A Simple, effective boron-halide ethoxylation catalyst
Moloy, Kenneth G.
, p. 821 - 826 (2010)
Boron esters B(OR)3, readily derived from boric acid and alcohols, combine with iodide or bromide to catalyze the ethoxylation of alcohols and phenols, giving good rates and narrow product distributions. The combined action of a weak electrophile [B(OR)3] and a weak nucleophile (halide) allows for the ethoxylation of base-sensitive alcohols. Experiment suggests a new mechanism for this commercially important reaction proceeding through key β-haloalkoxy intermediates.
Hydrogen bonding lowers intrinsic nucleophilicity of solvated nucleophiles
Chen, Xin,Brauman, John I.
, p. 15038 - 15046 (2008)
The relationship between nucleophilicity and the structure/environment of the nucleophile is of fundamental importance in organic chemistry. In this work, we have measured nucleophilicities of a series of substituted alkoxides in the gas phase. The functional group substitutions affect the nucleophiles through ion-dipole, ion-induced dipole interactions and through hydrogen bonding whenever structurally possible. This set of alkoxides serves as an ideal model system for studying nucleophiles under microsolvation settings. Marcus theory was applied to analyze the results. Using Marcus theory, we separate nucleophilicity into two independent components, an intrinsic nucleophilicity and a thermodynamic driving force determined solely by the overall reaction exothermicity. It is found that the apparent nucleophilicities of the substituted alkoxides are always much lower than those of the unsubstituted ones. However, ion-dipole, ion-induced dipole interactions, by themselves, do not significantly affect the intrinsic nucleophilicity; the decrease in the apparent nucleophilicity results from a weaker thermodynamic driving force. On the other hand, hydrogen bonding not only stabilizes the nucleophile but also increases the intrinsic barrier height by 3 to ～4 kcal mol-1. In this regard, the hydrogen bond is not acting as a perturbation in the sense of an external dipole but more directly affects the electronic structure and reactivity of the nucleophilic alkoxide. This finding offers a deeper insight into the solvation effect on nucleophilicity, such as the remarkably lower reactivities in nucleophilic substitution reactions in protic solvents than in aprotic solvents.
Selective synthesis of dimethoxyethane via directly catalytic etherification of crude ethylene glycol
Yu, Weiqiang,Lu, Fang,Huang, Qianqian,Lu, Rui,Chen, Shuai,Xu, Jie
, p. 3327 - 3333 (2017)
Etherification of ethylene glycol with methanol provides a sustainable route for the production of widely used dimethoxyethane; dimethoxyethane is a green solvent and reagent that is applied in batteries and used as a potential diesel fuel additive. SAPO-34 zeolite was found to be an efficient and highly selective catalyst for this etherification via a continuous flow experiment. It achieved up to 79.4% selectivity for dimethoxyethane with around 96.7% of conversion. The relationship of the catalyst's structure and the dimethoxyethane selectivity was established via control experiments. The results indicated that the pore structure of SAPO-34 effectively limited the formation of 1,4-dioxane from activated ethylene glycol, enhanced the reaction of the activated methanol with ethylene glycol in priority, and thus resulted in high selectivity for the desired products. The continuous flow technology used in the study could efficiently promote the complete etherification of EG with methanol to maintain high selectivity for dimethoxyethane.
Development of effective bidentate diphosphine ligands of ruthenium catalysts toward practical hydrogenation of carboxylic acids
Saito, Susumu,Wen, Ke,Yoshioka, Shota
, p. 1510 - 1524 (2021/06/18)
Hydrogenation of carboxylic acids (CAs) to alcohols represents one of the most ideal reduction methods for utilizing abundant CAs as alternative carbon and energy sources. However, systematic studies on the effects of metal-to-ligand relationships on the catalytic activity of metal complex catalysts are scarce. We previously demonstrated a rational methodology for CA hydrogenation, in which CA-derived cationic metal carboxylate [(PP)M(OCOR)]+ (M = Ru and Re; P = one P coordination) served as the catalyst prototype for CA self-induced CA hydrogenation. Herein, we report systematic trial- and-error studies on how we could achieve higher catalytic activity by modifying the structure of bidentate diphosphine (PP) ligands of molecular Ru catalysts. Carbon chains connecting two P atoms as well as Ar groups substituted on the P atoms of PP ligands were intensively varied, and the induction of active Ru catalysts from precatalyst Ru(acac)3 was surveyed extensively. As a result, the activity and durability of the (PP)Ru catalyst substantially increased compared to those of other molecular Ru catalyst systems, including our original Ru catalysts. The results validate our approach for improving the catalyst performance, which would benefit further advancement of CA self-induced CA hydrogenation.
Manganese catalyzed hydrogenation of carbamates and urea derivatives
Das, Uttam Kumar,Kumar, Amit,Ben-David, Yehoshoa,Iron, Mark A.,Milstein, David
supporting information, p. 12962 - 12966 (2019/08/26)
We report the hydrogenation of carbamates and urea derivatives, two of the most challenging carbonyl compounds to be hydrogenated, catalyzed for the first time by a complex of an earth-abundant metal. The hydrogenation reaction of these CO2-derived compounds, catalyzed by a manganese pincer complex, yields methanol in addition to amine and alcohol, which makes this methodology a sustainable alternative route for the conversion of CO2 to methanol, involving a base-metal catalyst. Moreover, the hydrogenation proceeds under mild pressure (20 bar). Our observations support a hydrogenation mechanism involving the Mn-H complex. A plausible catalytic cycle is proposed based on informative mechanistic experiments.
Monomeric alkoxide and alkylcarbonate complexes of nickel and palladium stabilized with the iPrPCP pincer ligand: A model for the catalytic carboxylation of alcohols to alkyl carbonates
Martínez-Prieto, Luis M.,Palma, Pilar,Cámpora, Juan
, p. 1351 - 1366 (2019/01/30)
Monomeric alkoxo complexes of the type [(iPrPCP)M-OR] (M = Ni or Pd; R = Me, Et, CH2CH2OH; iPrPCP = 2,6-bis(diisopropylphosphino)phenyl) react rapidly with CO2 to afford the corresponding alkylcarbonates [(iPrPCP)M-OCOOR]. We have investigated the reactions of these compounds as models for key steps of catalytic synthesis of organic carbonates from alcohols and CO2. The MOCO-OR linkage is kinetically labile, and readily exchanges the OR group with water or other alcohols (R′OH), to afford equilibrium mixtures containing ROH and [(iPrPCP)M-OCOOH] (bicarbonate) or [(iPrPCP)M-OCOOR′], respectively. However, [(iPrPCP)M-OCOOR] complexes are thermally stable and remain indefinitely stable in solution when these are kept in sealed vessels. The constants for the exchange equilibria have been interpreted, showing that CO2 insertion into M-O bonds is thermodynamically more favorable for M-OR than for M-OH. Alkylcarbonate complexes [(iPrPCP)M-OCOOR] fail to undergo nucleophilic attack by ROH to yield organic carbonates ROCOOR, either intermolecularly (using neat ROH solvent) or in intramolecular fashion (e.g., [(iPrPCP)M-OCOOCH2CH2OH]). In contrast, [(iPrPCP)M-OCOOMe] complexes react with a variety of electrophilic methylating reagents (MeX) to afford dimethylcarbonate and [(iPrPCP)M-X]. The reaction rates increase in the order X = OTs IMe ? OTf and Ni Pd. These findings suggest that a suitable catalyst design should combine basic and electrophilic alcohol activation sites in order to perform alkyl carbonate syntheses via direct alcohol carboxylation.
Influence of Boiling on the Radiolysis of Diglyme
Vlasov,Kholodkova,Ponomarev
, p. 312 - 318 (2018/08/01)
The radiolysis of diethylene glycol dimethyl ether (diglyme) in a boiling state has been studied for the first time. Boiling facilitates the cleavage of internal C–O bonds, weakens the cage effect and diglyme regeneration processes, and facilitates the exchange and dimerization reactions of radicals. As compared with radiolysis at room temperature, the amount of unsaturated products of diglyme fragmentation formed during irradiation in the boiling state is smaller by a factor of 4, and the disproportionation products of heavy radicals are found in negligible amounts, if any. The yield of radiolytic decomposition of diglyme under boiling conditions is ～15 molecule/100 eV, which is higher than that at room temperature by a factor of almost 1.5.
