Reaction Of Diol Research Articles

Vicinal effect on chlorination of diols

The vicinal effect on chlorination reactions of diols was investigated by computational methods. Applying density functional theory (DFT) combined with polarizable continuum model (PCM) and explicit solvent molecules, we demonstrated the effect of hydration on the leaving and vicinal hydroxyl group in SN2 reactions of selected alcohols. Our results point out to the importance of intermolecular hydrogen bonds as a stabilizing factor in reaction pre-complexes and alcohols with vicinal hydroxyl groups, highlighting the importance of solute-solvent network formation. This indicates the significance of adequately describing the solvent in the study of reaction mechanisms, in special when the interaction with solute molecules and ions are strong. Also, we found a “vinical effect” on the reactivity, in other words, alcohols with vicinal hydroxyl groups exhibit higher activation energies when compared to related monoalcohols. Moreover, 1,3-propanediol and 1,3-butanediol present the highest activation energies.

Degradable branched and cross-linked polyesters from a bis(1,3-dioxolan-4-one) core

Reaction of diols and triols with a bis(1,3-dioxolan-4-one) core derived from tartaric acid affords topologically diverse cross-linked and branched polyesters that are both reprocessable and hydrolytically degradable.

The Chemistry of Hager’s Test for Brucine

The purpose of the article is clear up what is happening in the test tube during the Hager’s test for brucine, that is, throughout the interaction of brucine with manganese dioxide in acidic medium. The paper is a Theoretical Organic Chemistry Study based on the chemical deportment of reagent and substrate, in accordance with the reaction medium. A series of reactions occur during the test: electrophilic attack to double bond, acidolysis of organometallic intermediates, oxidation of secondary alcohol to ketone, acid catalysed hydration, reaction of enol, epoxide formation, ring opening, selective reaction of diol, and ring cleavage of seven-member ring. A yellowish-red to blood-red colour is observed after filtering residual black manganese dioxide. This is due to halochromism, present in acidic medium, since there are no chromogenic groupings.

Ammonia versus Water Elimination in the Reaction of Diols with Urea under Metal Oxide Catalysis

Ammonia versus Water Elimination in the Reaction of Diols with Urea under Metal Oxide Catalysis

Polyethylene Glycol-Isophorone Diisocyanate Polyurethane Prepolymers Tailored Using MALDI MS.

The reaction of diols with isocyanates, leading to mono-functional and di-functional prepolymers may be investigated using various characterization methods which show the overall conversion of isocyanate monomers. On the other hand, matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) polymer characterization can be employed to identify the monomer units, the end-group functionalities, molecular weight averages, and to determine the copolymer sequence. Herein, we focus on prepolymer synthesis using isophorone diisocyanate (IPDI), a widely used diisocyanate for prepolymers preparation, especially in waterborne polyurethane materials. Thus, the reaction between polyethylene glycol diol and IPDI was in-depth investigated by mass spectrometry to determine the influence of the reaction parameters on the prepolymer's structure. The relative content of the different functional oligomer species at given reaction times was determined in the reaction mixture. More specifically, the offline analysis revealed the influence of reaction parameters such as reaction temperature, the concentration of reactants, and the amount of dibutyltin dilaurate catalyst. The established MALDI MS analysis involved measurements of samples, first, directly collected from the reaction mixture and secondly, following derivatization with methanol. The obtained results revealed the effects of reaction parameters on the functionalization reaction with isocyanates, allowing to achieve a better reaction control.

"In-water" Dehydration Reaction of an Aromatic Diol on an Inorganic Surface.

The effect of a synthetic saponite surface on the "in-water" dehydration reaction of diol was examined using 4-formyl-1-methylquinolinium salt (MQu+) as a substrate. The equilibrium between aldehyde (MQu+-Aldehyde) and diol (MQu+-Diol) was affected by the surrounding environment. The equilibrium behavior was observed by 1H nuclear magnetic resonance (NMR) and UV-vis absorption measurements. Although MQu+ was completely in the form of MQu+-Diol in water, the equilibrium almost shifted to the MQu+-Aldehyde side when MQu+ was adsorbed on the saponite surface in water. In addition, the MQu+-Aldehyde ratio depended on the negative charge density of saponite. The factors that determine MQu+-Aldehyde: MQu+-Diol ratio were discussed from the thermodynamic analysis of the system. These data indicate that the electrostatic interaction between the charged saponite surface and MQu+ stabilized the aldehyde side enthalpically and destabilized it entropically. The major reason for these results is considered to be the difference in adsorption stabilization between MQu+-Aldehyde and MQu+-Diol on saponite surfaces.

Catalytic synthesis of terpenoid-derived hexahydro-2H-chromenes with analgesic activity over halloysite nanotubes

Condensation of α-pinene derived p-menta-1,8-diene-5,6-diol (diol) with decanal was studied for the first time over modified halloysite nanotubes (HNT). The yield of the desired hexahydro-2H-chromene-4,8-diol with analgesic activity was 76–80 % practically not depending on the catalyst type, while selectivity to 4S-isomer decreased, and to 4R-isomer increased with increasing acidity. The highest selectivity to 4S-diastereomer (48.1 %) on halloysite is a result of weak acidity of this catalyst. DFT optimization of the key intermediate structure shows that the nucleophile attack proceeds at the equatorial position with the 4S-diastereomer formation, which was preferred on halloysite. On strong Brønsted (Amberlyst-15) and Lewis (scandium triflate) acids the target product yield did not exceed 37 % because of dehydration. Halloysite nanocatalysts displayed a stable performance. In the case of diol reaction with a set of carbonyl compounds, the yields of hexahydro-2H-chromene-4,8-diols (up to 88.0%) and the ratio of its 4S/4R isomers (up to 21.0) were significantly higher than on other catalysts.

Research Progress of N-Alkylation of Alcohol and Amine by "Hydrogen Reaction"

Amine compounds are widely found in natural products, pharmaceuticals and fine chemical products. Therefore, it is of great significance to develop methods for synthesizing amine compounds. Therefore, in recent years, a new method of synthesizing amines has been developed, namely "hydrogen borrowing reaction". This article reviews the alkylation of primary alcohols and amines, the cyclization of amino alcohols to form N-heterocyclic compounds, the reaction of diols and amines to form N-heterocyclic compounds, the reaction of alcohols and sulfonamides, and the reaction of alcohols and amines containing N heteroatoms , Alcohol and ammonia gas and ammonia to produce amine by hydrogen reaction research progress.

Fabrication and Characterization of Polyvinyl Chloride/Copolyester/Nanoclay Composite Nanofiber

Four random copolyesters were prepared by the polycondensation reaction of diols namely 1,5-dihydroxyanthraquinone, 4,4′-oxybis(benzoic acid) and variable chalcone diol. Four chalcone diols were produced by acid catalyzed Claisen-Schmidt reaction at room temperature. These random copolyesters were elucidated by solubility tests and viscosity measurements. The FT-IR, 1H & 13C NMR techniques were applied to establish the repeating units present in the copolyester backbone. Electrospinning method was employed to derive polyvinyl chloride-copolyester-nanoclay composite nanofiber from tetrahydrofuran medium. Scanning electron microscopy (SEM) was utilized to examine the morphology of the nanofibers. These composite nanofibers are expected to be a potential biomaterial of greater significance.

Ruthenium(0)-Catalyzed Cycloaddition of 1,2-Diols, Ketols, or Diones via Alcohol-Mediated Hydrogen Transfer.

Merging the characteristics of transfer hydrogenation and carbonyl addition, a broad new class of ruthenium(0)-catalyzed cycloadditions has been developed. As discussed in this Minireview, fused or bridged bicyclic ring systems are accessible in a redox-independent manner in C-C bond-forming hydrogen transfer reactions of diols, α-ketols, or 1,2-diones with diverse unsaturated reactants.

Sustainable Catalytic Amination of Diols: From Cycloamination to Monoamination

N-Alkyl amines are extensively applied in the synthesis of functional materials, pharmaceuticals, and pesticides. The reaction of diols with amines is attractive and has been investigated for more than 30 years by using iridium, ruthenium, and other catalysts. However, the main products with diols as starting materials, especially for C4–C6 diols, are N-heterocyclic compounds because cyclization reaction is favorable in thermodynamics. Here, for the first time, a simple and non-noble catalyst CuNiAlOx prepared by a coprecipitation method was developed for the reaction of C4–C6 diols with amines to give monoamination products. This method offers an efficient and environmentally friendly method for the selective monoamination of diols.

Bidentate reagents form cyclic organic-Cr(VI) molecules for aiding in the removal of Cr(VI) from water: density functional theory and experimental results

Hexavalent chromium, Cr(VI), in the form of chromate (CrO4 2−) or dichromate (Cr2O7 2−) is a well-described carcinogen found in the drinking water in many parts of the country at levels deemed unsafe by the U.S. Environmental Protection Agency and the World Health Organization. We report on the ability of bidentate organic molecules containing diols or diamines to capture chromate ions from aqueous sources by forming cyclic organic-Cr(VI) carbonates or ureas. After their formation, the cyclic organic-Cr(VI) molecules are readily absorbed onto granulated activated charcoal to facilitate Cr(VI) removal. Using density functional theory, E 0 values for the reactions of diols and diamines with chromate were calculated and correlated with the experimental findings of Cr(VI) removal.

Synthesis, characterization and properties of novel blue light emitting discrete π-functional polymer consisting of carbazole and anthracene units and their applications in polymer light emitting diodes

A new novel blue light emitting polymer containing carbazole and anthracene derivatives has been successfully synthesized via polycondensation chemical reaction of diol and difluoro monomers. An effort has been made to raise the band gap of blue light emitter by lowering the conjugation extent in the backbone. The synthesized blue polymer exhibits decent solubility, good process ability, high thermal stability, high glass transition temperature (272 °C) and the decomposition temperature of 358 °C. The UV-vis absorption spectra and photoluminescence spectra depict that the light emission lies in blue region. The solid state photoluminescence (PL) spectra of the polymer (λPL = 456 nm) shows red shift (Δλ = 37 nm) as compared with the corresponding solution PL spectra, presumably due to lower intermolecular distance in solid state. The multi-layered polymer light emitting diode was fabricated, using blue polymer with ITO/PEDOT: PSS/BP/LiF/Al architecture. The luminance-voltage (L-V) and current density-voltage (J-V) curves show a maximum luminance of 7544 cd m−2, a maximum emission efficiency of 4.2 cd A−1, a maximum current density of 453 mA cm−2 at a turn-on voltage of 4.5 V. Moreover, the PLED instigate pure blue EL emission, stable at 436 nm with outstanding CIE coordinates of (x = 0.15, y = 0.08), which is close to the pure NTSC blue coordinates of (0.14, 0.08).

Selective, sensitive and reliable colorimetric sensor for catechol detection based on anti-aggregation of unmodified gold nanoparticles utilizing boronic acid–diol reaction: optimization by experimental design methodology

A sensitive and selective colorimetric method is presented for quantitative analysis of catechol based on the unmodified gold nanoparticles (AuNPs). In the absence of catechol, the addition of 4-mercaptophenyl boronic acid (MPBA) instigates the aggregation of AuNPs by Au–S covalent binding via self-dehydration condensation of boronic acid groups and causes a noticeable color alteration of AuNPs from wine red to blue. In the presence of catechol, boronic acid–diol binding is preferred than to the self-dehydration condensation. An increase in catechol concentration alleviates AuNPs aggregation by decreasing the amount of free MPBA, and solution color changes from blue to red. Therefore, the concentration of catechol can be detected with the naked eye or by an ultraviolet–visible spectrophotometer. Central composite design and response surface methodology were executed to evaluate interactions among variables. Due to the preference for the binding of 1,2-diol to boronic acid, this method showed high selectivity for catechol determination compared to dihydroxybenzene isomers with a linear response range of 0.87–56 µmol L−1 with a detection limit of 0.41 µmol L−1. The proposed colorimetric sensing method exhibits the advantage of no necessity for surface modification of AuNPs, avoids tedious separation processes and enables rapid assays. A highly sensitive sensing platform for catechol was established based on the anti-aggregation of AuNPs without prior modification through a competition reaction of boronic acid–diol binding between 4-mercaptophenyl boronic acid (MPBA) and catechol against the self-dehydration condensation of MPBA.

Recent Progress in Re-Catalyzed Dehydroxylation Reactions

The development of novel effective processes for the conversion of abundant renewable resources to fuels and value-added chemicals has spurred new interest in the discovery of selective chemical transformations of polyols and carbohydrates. These compounds have high oxygen content, which is mostly present in the form of hydroxyl groups. Therefore, partial or complete removal of the hydroxyl groups is of great importance. Herein a brief overview on the development of rhenium-catalyzed dehydroxylation reactions in recent years is given, which are roughly classified into two categories: (1) dehydroxylation reactions of monools for new chemical bond formation and (2) dehydroxylation reactions of diols and polyols for olefin syntheses.

Reactions of diols with dimethyl carbonate in the presence of W(CO)6 and Co2(CO)8

Dimethoxyalkanes and dimethyl alkanediyl biscarbonates were synthesized by reactions of diols with dimethyl carbonate in the presence of tungsten and cobalt carbonyls. Optimal reactant and catalyst ratios and reaction conditions were found to ensure selective formation of dimethoxyalkanes or dimethyl alkanediyl biscarbonates.

Synthesis of alkylene carbonates in ionic liquid

Alkylene carbonates are widely used in industry as solvents, heat carriers, plasticizers, monomers, and intermediate products in organic synthesis. Traditional methods of synthesis of alkylene carbonates (as well as of starting compounds) utilize toxic compounds (phosgene, alkylene oxides) and often require elevated pressure, which involves high operational risks. At present, much attention is given to phosgenefree syntheses of organic carbonates. For this purpose, new catalytic systems promoting reactions of alkylene oxides with carbon dioxide have been proposed, e.g., ionic liquids [1, 2], alkali metal chlorides in combination with macrocyclic chelating compounds [3], dibutyltin oxide and methoxide [4]. However, all these reactions occur under elevated pressure. Alternative procedures are based on reactions of diols with urea on heating to 170°C [5] in the presence of a mixture of metal acetates and alkoxides [6] and oxide catalysts [7] under excess pressure. Alkylene carbonates can also be prepared by transesterification with the corresponding diols of dialkyl carbonates synthesized by a phosgenefree procedure [8]. We now propose a new synthesis of alkylene carbonates from urea and alkylene glycols, which requires neither elevated pressure nor high temperature. The reactions are carried out in a two-phase system consisting of a ionic liquid and a chlorinated organic solvent. As ionic liquid we used a mixture of equimolar amounts of a metal chloride, urea, and glycol [9], which formed a colorless transparent solution on heating above 50°C. The yields attained 80%. The reactions were carried out with a number of glycols and metal chlorides. A mixture of 3.71 g (22.7 mmol) of zinc(II) chloride sesquihydrate ZnCl2 · 1.5 H2O, 1.36 g (22.7 mmol) ISSN 1070-4280, Russian Journal of Organic Chemistry, 2013, Vol. 49, No. 12, pp. 1859–1860. © Pleiades Publishing, Ltd., 2013. Original Russian Text © V.A. Kuznetsov, M.G. Pervova, A.V. Pestov, 2013, published in Zhurnal Organicheskoi Khimii, 2013, Vol. 49, No. 12, pp. 1874–1875.

ChemInform Abstract: Indium(III) Triflate Catalyzed Transacetalization Reactions of Diols and Triols under Solvent‐Free Conditions.

AbstractAcyclic acetals and ketals undergo transacetalization with diols and triols in the presence of catalytic amounts of indium(III) triflate under solvent‐free conditions to generate the corresponding cyclic acetals and ketals in high yields.

ChemInform Abstract: A Facile Synthesis of 5,6‐Dihydro‐4H‐pyrrolo[3,4‐d]thiazole and Other Pyrrolidine‐Fused Aromatic Ring Systems via One‐Step Cyclization from Diols.

AbstractThe desired 5,6‐dihydro‐4H‐pyrrolo[3,4‐d]thiazole (VII) is readily prepared via a Mitsunobu reaction of diol (IV) with sulfonamide (V).

Indium(III) triflate catalysed transacetalisation reactions of diols and triols under solvent-free conditions

Acyclic acetals and ketals undergo transacetalisation in the presence of catalytic quantities of indium(III) triflate (In(OTf)3) and diols or triols under solvent-free conditions to generate the corresponding cyclic acetals and ketals in excellent yield. The methodology has been further developed to encompass a tandem acetalisation-acetal exchange protocol, which provides a facile and high yielding route to cyclic ketals from unreactive ketones under very mild reaction conditions.