Alcohols In Acidic Media Research Articles

Redox Kinetics and Mechanism of the Reactions of µ –Oxobis [aquobis (2,2’ – Bipyridine)] diruthenium (III) Ion and some Aliphatic Alcohols in Acidic Medium

The redox kinetics and mechanisms of the reactions of μ – oxobis[aquobis(2,2’ - bipyridine)]diruthenium (III) ion, [(bipy)2(H2O)RuORu(H2O)(bipy)2]4+ (hereafter denoted as Ru2O4+ or [(H2O)2(bipy)4Ru2O]4+) and some primary aliphatic alcohols was studied in perchloric acid medium, [H+] = 5.0 x 10-3 mol dm-3, ionic strength (I), = 0.5 mol dm–3 (NaClO4), temperature (T) = 31 ± 1°C and wavelength ,λmax = 660 nm. The reactions, which led to the formation of corresponding aldehydes had a stoichiometry of 1:1, were all first order with respect to each reactant, and second order overall. The reactions proceeded in the absence of acid but when acid was added, the reactions ceased. Varying the ionic strength and dielectric constants of the reaction medium had no effect on the reaction. Added ions catalysed the reaction and free radicals were identified in the reaction mixtures in the course of the reactions. There was no evidence for the formation if intermediate complex in the course of the reaction. The order of reactivity is of the order CH3OH > C2H5OH > C3H7OH Based on the results, it is suggested that all the reactions proceeded through the outer – sphere electron transfer mechanism and a plausible mechanism that represented all the reactions is proposed.

Development of technology for the alkylation of hydroquinone with aliphatic alcohols

The paper presents the results of research of technology of alkylation of hydroquinone, propyl, isopropyl, isobutyl and tert-butyl alcohols in the presence of concentrated phosphoric acid. The temperature of the alkylation reaction was maintained between 70–72 °С. On the basis of literature data and preliminary investigations the reaction was performed for 4 hours. Upon completion of the reaction, we removed the unreacted hydroquinone, aliphatic alcohol and phosphoric acid are added to a solution of distilled water (solvent corresponding connections) and sodium bicarbonate to slightly acidic (pH 5–6). For separation from the reaction medium of alkylhydroquinones in the reaction mixture was added benzene in which the original hydroquinone dissolves much less. Concentration of the benzene extract alkylhydroquinones conducted by Stripping the solvent under vacuum at temperatures above 70 °С in air atmosphere. Higher temperature vacuum distillation AIDS in the oxidation of alkylhydroquinones to alkylphenones. Precipitated after crystallization, alkylhydroquinones were dried under vacuum in a drying pistol at 56 °С. Dried products were identified by defining the melting temperature, the study of spectral characteristics and qualitative reactions with FeCl3. We also studied the solubility of alkylhydroquinones in various solvents, which showed low solubility of alkylhydroquinones in water, benzene, toluene and higher solubility in propyl and isopropyl alcohols and in acetone. Analysis of the results shows that the obtained alkylhydroquinones are not chemically pure compounds, and contain in their composition of admixture source of hydroquinone. Qualitative reactions of solutions of alkylhydroquinones with FeCl3 solution differ from the corresponding reaction of a solution of hydroquinone. The results of investigations of electronic absorption spectra of alkylhydroquinones and source of hydroquinone in isopropyl alcohol solution did not significantly differ from each other and have a maximum absorption at ? = 210 nm. From the presented investigations it follows that the maximum efficiency of the alkylation of hydroquinone was studied aliphatic alcohols in acidic medium is observed for t-butyl alcohol.

Tuning the Reactivity of Functionalized Diallylic Alcohols: Brønsted versus Lewis Acid Catalysis.

The chemodivergent reactivity of bifunctional, enol thioether-containing diallylic alcohols in acidic medium is disclosed, highlighting the difference between strong Lewis acid and mild Brønsted acid catalysis. In the presence of bismuth(III) triflate, allylic alcohol activation affords diversely substituted cyclopentenones in a Nazarov-type electrocyclization, whereas activation of the thioenol ether by p-toluenesulfonic acid provides an entry to α-sulfenylated β,γ-unsaturated ketones. Both methods represent a facile access to the corresponding products under mild conditions, using inexpensive and non-toxic catalytic systems.

Synthesis of fluoro-substituted acrylic monomers bearing a functionalized lateral chain: Part 1. Preparation of sulfur-containing monomers

The synthesis of sulfur-containing fluoroacrylic monomers CmF2m+1(CH2)2S(CH2)nOC(O)CHCH2 (where m=6, 8 and n=2–4, 11) is presented from a two-step procedure. The first deals with the radical addition of fluorinated mercaptans CmF2m+1(CH2)2SH onto ω-unsaturated alcohols leading to new ω-perfluorinated alcohols containing various polymethylene spacers CmF2m+1(CH2)2S(CH2)nOH according to the nature of the unsaturated alcohols. By-products were noted, resulting from the β-addition of the thiyl radical onto the more hindered side of the alcohol. The proportion of linear and branched isomers is discussed according to the stability of the radical intermediates. These minor products were obtained selectively from other routes to confirm their presence in the reaction media. The second step deals with the acrylation reaction that occurred either in the presence of acryloyl chloride or from a Fisher esterification. Both reactions are described and discussed taking into account the nature of the starting alcohols. The formation of thiiranium ions as intermediates in the esterification of β-sulfur-containing alcohols in acidic medium is established and the formation of regioisomers described according to this thiiranium moieties interposition.

Ultrasound in carbohydrate chemistry: sonophysical glucose oligomerisation and sonocatalysed sucrose oxidation

Both aspects of the interest in using ultrasound are illustrated by our results in the field of carbohydrate chemistry. The course of the heterogeneous reaction of glucose with hydrophobic alcohols in acidic medium is directed towards the oligomerisation of glucose because of the wetting of the glucose suspension due to the efficiency of the sonophysical mixing. On the other hand, a sonocatalysis is observed during the course of the oxidation of primary hydroxyl groups in homogeneous aqueous medium by the NaOCl/TEMPO system.

Furo-fused 2H-chromenes: synthesis and photochromic properties

New photochromic chromenes annulated with a furan ring have been synthesized. Thus, suitable heterocyclic phenols react with different propargylic alcohols in acidic medium to give the corresponding ethers, which cyclize into benzopyrans by thermal Claisen rearrangement. This synthetic approach was found to lead to a mixture of linear and angular chromenes that is strictly related to the nature of the phenol. However, regiospecificity could be obtained by reacting β-phenylcinnamaldehyde, in refluxing aprotic nonpolar solvents, with titanium(IV) salts of the former phenols. Electrocyclization of intermediately generated o-quinoid structures occurs on the α position towards the heterocyclic junction. All compounds exhibit photochromic behavior at room temperature. Furo-fused benzopyrans are particularly interesting with respect to naphthopyran parents in view of the bathochromically shifted and broadened absorption spectra of photoinduced forms. This trend is confirmed by the spectral data of several heterocyclospiro(7H-furo[3,2-f] chromenes). The achievable color depends significantly on the relative position of annulation on the chromenic moiety and substitution on the sp3 carbon atom. Key words: photochromism, heterocycle, regiospecificity, 2H-chromene, furan.

A new method for the chiral HRGC assay of L‐2‐hydroxyglutaric acid in urine

AbstractL‐2‐Hydroxyglutaric aciduria is a recently discovered inherited neurometabolic disease for which diagnostic identification of the right enantiomer is required. A method is described where alkyl esters of both L‐and D‐2‐hydroxyglutaric acids are prepared without side lactonization. Esterification is achieved at room temperature by reaction with appropriate alkyl chloroformates. This method avoids lactonization, in contrast to esterification with alcohols in acidic media or with diazomethane. The identity of the derivatives is established by HRGC‐FTIR and HRGC‐MS. Chiral HRGC separation with capillaries coated with 1(R)‐trans‐N‐N'‐1,2‐cyclohexylenebisbenzamideoligodimethyL‐siloxane and with a cyclodextrin is compared. The method is adequate for quantitative determinations.

ChemInform Abstract: Formation of o‐Nitroso(alkylamino)benzenes by Reaction of Benzofurazans with Alcohols in Acidic Media.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: α,α‐Dialkoxyarylketones and Related Compounds. Part 1. Reaction of Phenylglyoxal with Primary Alcohols in Acidic Medium.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Reactions of stereoisomeric 3,4-epoxycaranes with alcohols in acidic media

In the reaction of the cis-isomer of 3,4-epoxycarane with alcohols in acidic media, opening of the oxide ring was less regioselective than in the case of the α-isomer. Rearrangement of the trans-isomer of 3,4-epoxycarane with transannual cyclopropyl participation occurs only in reactions with a secondary alcohol.

Mechanism of Ru(III) Catalysis in Bromamine-T Oxidation of Some Primary Alcohols in Acidic Media

Mechanism of Ru(III) Catalysis in Bromamine-T Oxidation of Some Primary Alcohols in Acidic Media

μ-Bis(cyanotrihydroborato)-tetrakis(triphenylphosphine) dicopper(I). A new, selective, pH dependent reducing agent

The title compound selectively reduces acid chlorides to aldehydes under neutral conditions and aldehydes and ketones to alcohols in acidic media. 4- tert -Butylcyclohexanone is reduced to the trans alcohol with a high degree of stereoselectivity (94:6).

Une nouvelle synthese de l'ellipticine et ses analogues structuraux

Two new syntheses of the 6 H-pyrido [4,3-b] carbazole system are described. The first method involves the cyclization of a (2-alkyl-skatyl)-piperidone whereas the second leads to ellipticine by the participation of the indole nucleus in the rearrangement of tertiary acetylenic alcohols in acidic medium.

362. The kinetics of hydrogen isotope exchange reactions. Part XII. The behaviour of primary alcohols in acidic media

362. The kinetics of hydrogen isotope exchange reactions. Part XII. The behaviour of primary alcohols in acidic media