Secondary Alkanols Research Articles

One-pot esters synthesis from secondary alcohols and CO catalyzed byPd-phosphine systems

The aim of the work is to develop the esters syntheses by combining in one reactor the acid–catalytic intramolecular alcohols dehydration and the resulting alkenes alkoxycarbonylation. Esters were synthesized from cycloalkanols or secondary alkanols C5–C9 and CO under mild conditions. For the first time, a wide range of catalytic systems including palladium precursor, organophosphine, strong protonic acid, and additive for binding water have been tested in the model one-pot process based on cyclohexanol and CO. For the first time, the dehydration processes of secondary linear alcohols C6, C7 and C9 were combined in one reactor with isomerizing alkoxycarbonylation catalyzed by Pd-systems with the XANTPHOS promoter. These processes led to the isomeric esters formation, among which 60–73% were linear carboxylic acid esters as products of terminal CO addition to alkenes.

Directing the Rate-Enhancement for Hydronium Ion Catalyzed Dehydration via Organization of Alkanols in Nanoscopic Confinements.

Alkanol dehydration rates catalyzed by hydronium ions are enhanced by the dimensions of steric confinements of zeolite pores as well as by intraporous intermolecular interactions with other alkanols. The higher rates with zeolite MFI having pores smaller than those of zeolite BEA for dehydration of secondary alkanols, 3‐heptanol and 2‐methyl‐3‐hexanol, is caused by the lower activation enthalpy in the tighter confinements of MFI that offsets a less positive activation entropy. The higher activity in BEA than in MFI for dehydration of a tertiary alkanol, 2‐methyl‐2‐hexanol, is primarily attributed to the reduction of the activation enthalpy by stabilizing intraporous interactions of the Cβ‐H transition state with surrounding alcohol molecules. Overall, we show that the positive impact of zeolite confinements results from the stabilization of transition state provided by the confinement and intermolecular interaction of alkanols with the transition state, which is impacted by both the size of confinements and the structure of alkanols in the E1 pathway of dehydration.

Directing the Rate‐Enhancement for Hydronium Ion Catalyzed Dehydration via Organization of Alkanols in Nanoscopic Confinements

AbstractAlkanol dehydration rates catalyzed by hydronium ions are enhanced by the dimensions of steric confinements of zeolite pores as well as by intraporous intermolecular interactions with other alkanols. The higher rates with zeolite MFI having pores smaller than those of zeolite BEA for dehydration of secondary alkanols, 3‐heptanol and 2‐methyl‐3‐hexanol, is caused by the lower activation enthalpy in the tighter confinements of MFI that offsets a less positive activation entropy. The higher activity in BEA than in MFI for dehydration of a tertiary alkanol, 2‐methyl‐2‐hexanol, is primarily attributed to the reduction of the activation enthalpy by stabilizing intraporous interactions of the Cβ‐H transition state with surrounding alcohol molecules. Overall, we show that the positive impact of zeolite confinements results from the stabilization of transition state provided by the confinement and intermolecular interaction of alkanols with the transition state, which is impacted by both the size of confinements and the structure of alkanols in the E1 pathway of dehydration.

Competing intramolecular vs. intermolecular hydrogen bonding in phosphoryl-containing secondary alkanols: A structural, spectroscopic and DFT study

Intramolecular hydrogen bonding competes with intermolecular hydrogen bonding in alkanols containing Ph2P(O) group. A character of H-bonding in secondary alkanols Ph2P(O) (CR2)nCH2CH(OH)Me, where n = 0 (1), n = 1, R = H (2), and n = 1, R = Me (3) in crystal state and solutions has been studied by X-ray diffraction, FTIR, and diffusion ordered NMR spectroscopy (DOSY). Quantum chemical calculations and QTAIM analysis of isolated alkanol molecules and their dimers have been performed. In spite of slight difference in the structure of linker between P(O) and OH groups, the studied alcohols in crystal exhibit three types of H-bonds: dimer with intermolecular H-bond, polymeric chains with intermolecular H-bond, and monomer with intramolecular H-bond. Experimental data agree well with structural data of quantum chemical calculations at the M06-2x/6-311G (d,p) level of theory. Energy values (thermodynamic parameters) of DFT-optimized structures for gauche and anti isomers and dimers have been calculated. According to FTIR data in solutions (0.1–0.0001 M), alcohol 1 is the most associated, association of alcohol 2 is much less expressed, while alcohol 3 remains as H-bound monomer. Particle size assessed by DOSY relative to Ph3CH does not change on dilution for alcohols 2 and 3 but varies for alcohol 1.

Detection of secondary alkanols in Neogene sediments of the Shinjo basin, Japan : possible thermal hydration reaction products

Detection of secondary alkanols in Neogene sediments of the Shinjo basin, Japan : possible thermal hydration reaction products

Excess molar enthalpies of ethane-1,2-diamine plus primary and secondary alkanols (C1–C4) and correlation with Redlich-Kister, Wilson, NRTL and UNIQUAC models at T = 298 K

Excess molar enthalpies, HmE of binary mixtures of ethane-1,2-diamine (EDA) with methanol, ethanol, propan-1-ol, propan-2-ol, butan-1-ol and butan-2-ol were calculated from calorimetric data at T=298K and atmospheric pressure (81.5kPa) with a Parr 1455 solution calorimeter. All the binary mixtures showed exothermic behavior over the entire range of compositions. From the experimental results, the excess partial molar enthalpies, HiE and excess partial molar enthalpies at infinite dilution, HiE,∞ were calculated. Excess molar enthalpies, HmE values increase as the chain length of the alkanol is increased, showing minimum values varying from −4395 (methanol) to −1987 J·mol-1 (butan-2-ol). The minimum HmE values were observed about 0.4mol fraction of ethane-1,2-diamine (EDA). The experimental results were discussed in terms of intermolecular interactions, particularly hydrogen-bonding interactions between like and unlike molecules. Finally the experimental results were correlated by the Redlich–Kister equation and the three thermodynamic models (Wilson, NRTL, and UNIQUAC) based on the local composition theory.

α- and β-diphenylphosphorylated secondary alkanols: I. general method of synthesis and extraction properties towards f-elements

A simple and effective general method of synthesis of α- and β-diphenylphosphorylated secondary alkanols by the reduction of the corresponding phosphorylalkanones with NaBH4 was developed. The extraction properties of the resulting phosphorylalkanols Ph2P(O)(CR2)nCH2CH(OH)Me (n = 0, 1; R = H, Me) were studied in the recovery of f-elements (LaIII, NdIII, HoIII, YbIII, UVI, ThIV) from nitric acid solutions into chloroform and compared with those of both related phosphorylketones and known extractants (n-BuO)3PO, (n-C8H17)3PO, and Ph2P(O)CH2C(O)N(n-Bu)2.

Predicting the physical–chemical properties of biodiesel fuels assessing the molecular structure with the SAFT−γ group contribution approach

The properties of biodiesel as fuel are strongly defined by the molecular structure of its constituent species (saturated, unsaturated and hydroxylated fatty acid alkyl esters). Improving fuel properties and energetic patterns in biodiesel implies optimising its fatty ester structures and compositions. Biodiesel fuels derived from different sources can have significantly varying fatty acid profiles and properties, which claims for the theoretical prediction of the thermophysical and phase equilibria properties of biodiesel compounds and its mixtures. In this work the SAFT-γ (Statistical Associating Fluid Theory by group contribution) is applied for predicting these properties in biodiesel fuels by adequately representing the physical behaviour and stereochemistry of biodiesel molecules. A realistic representation of the molecular structure of long chain methyl esters and esters that contains hydroxyl groups, which are the typical biodiesel fuel constituents, is obtained. We implemented a simplex simulated annealing algorithm as global optimisation method to determine the SAFT-γ parameters for the groups that fully represent the biodiesel compounds, which were fitting to experimental data available for analogous chemical families like secondary alkanols and short chain esters. These parameters are theoretically justifiable following physically meaningful trends and can be generalised to others fatty acid methyl esters in the same homologous series. The group of like and unlike parameters obtained were used to represent the thermophysical properties of several commercial biodiesel fuels. The theory provides a very good description of the liquid vapour equilibria behaviour of the chemical families used to estimate the set of parameters. With the proposed model, any potential biodiesel fuel from any feedstock can be represented and modelled.

Tin(II) Chloride Mediated Coupling Reactions between Alkynes and Aldehydes

AbstractTin(II) chloride, which is insensitive to water and air, mediated the coupling reaction between alkynes and aldehydes as a Lewis acid in nitromethane to produce (E)‐α,β‐unsaturated ketones by a skeletal transformation in which one alkynic carbon atom changed into an oxo carbon atom accompanied by the cleavage of a C=O bond in the starting aldehydes. This coupling reaction was promoted by a catalytic amount of a primary or secondary alkanol. The coupling reaction between 1‐deuterio‐2‐phenylethyne and benzaldehyde with BuOH afforded 1,3‐diphenyl‐2‐deuterio‐2‐propenone (2‐deuteriation: 94 % D), whereas the coupling reaction between phenylethyne and benzaldehyde with BuOD afforded 1,3‐diphenyl‐2‐propenone (2‐deuteriation: 0 % D). Because almost no exchange between hydrogen and deuterium at the 2‐position of 1,3‐diphenyl‐2‐propenone occurs in either of the reactions, the coupling reaction between alkynes and aldehydes with tin(II) chloride is presumed to proceed by nucleophilic addition of alkynes to aldehydes. The cleavage of the C–O single bond generated by the nucleophilic addition might be induced by the strong oxophilicity of tin.

ChemInform Abstract: Oxidation of Primary and Secondary Alkanols with the CeIII—LiBr—H2O2 System.

AbstractIn organic oxidations the system CeIII—LiBr—H2O2 is used for the first time.

ChemInform Abstract: Oxidation of Alkanols with CeIII—LiBr—H2O2 System.

AbstractOxidation of primary and secondary alkanols to esters and ketones, resp., is achieved using a Ce(NO3)2—LiBr—H2O2 systems.

Oxidation of primary and secondary alkanols with the CeIII-LiBr-H2O2 system

Action of a novel oxidation system, Ce(NO3)3·6H2O (cat.)-LiBr (cat.)-H2O2 (stoichiometric oxidant) on primary aliphatic C6–C9 alcohols gives selectively esters, whereas secondary aliphatic C5–C9 alcohols are converted into ketones. Selectivity of these transformations is provided by slow addition of H2O2 to the other reactants.

Oxidation of secondary alkanols with the system cerium ammonium nitrate—lithium bromide into ketones, α-bromo ketones, and α,α′-dibromo ketones

Oxidation of secondary alkanols with the system Ce(NH4)2(NO3)6—LiBr in aqueous acetonitrile gave ketones, α-bromo ketones, or α,α′-dibromo ketones. The selectivity of the reaction under standard conditions depends only on the molar ratio of the reagents (alkanol: CeIV: LiBr).

New Efficient Synthesis of 2‐Substituted Benzothieno[3,2‐d]pyrimidin‐4(3H)‐ones via a Tandem Aza‐Wittig Reaction.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Occurrence of long-chain n-alkenols, diols, keto-ols and sec-alkanols in a sediment core from a hypereutrophic, freshwater lake

Long-chain mid-chain diols and keto-ols have been reported mainly in marine environments but only rarely in lacustrine sediments. In this work, exceptionally high abundances and diversity of keto-ols, diols and structurally related long-chain n-alkenols and secondary alkanols were detected in sediments from a hypereutrophic, freshwater lake (Lake Valencia, Venezuela). The maximum concentrations are 241 μg/g TOC for n-alkenols, 75 μg/g TOC for diols, 367 μg/g TOC for keto-ols, and 8.7 μg/g TOC for secondary alkanols. Eleven keto-ol isomers were identified, which is the highest diversity yet reported for sediments. The presence of five keto-ol isomers, namely 1,12-C 30 keto-ol, 1,14-C 31 keto-ol, 1,15-C 33 keto-ol, 1,16-C 33 keto-ol and 1,18-C 35 keto-ol is reported for the first time. The mass spectra for osmium tetroxide derivatives from long chain n-alkenols confirmed the double bond location at carbons 13, 14 or 15. The carbon isotope compositions were substantially enriched in 13C for n-alkenols, diols and keto-ols ( δ 13C = −22.0 ± 2.2‰) relative to the corresponding long-chain n-alkanols (−29.6 ± 0.8‰), suggesting an autochthonous aquatic microbial origin rather than from a terrestrial (i.e., fern) source. Although a strong predominance of cyanobacteria was reported for in the lake’s plankton community (>90%) and relatively low abundance of sedimentary sterols suggests cyanobacteria as a potential source, eustigmatophytes, a major reported producer of diols and keto-ols, cannot be excluded because eustigmatophytes are easily confused with other microalgae and may have been overlooked in previous studies. n-Alkenols and keto-ols displayed similar historical patterns over the past 10,000+ years, but there were distinct differences from the diol patterns. This result suggested that n-alkenols and keto-ols may be derived from the same sources, while diols either undergo different environmental diagenesis or have different sources. A keto-ol index coincides well with the hydrological changes of Lake Valencia over the last 10,000+ years, and corroborates its validity as a paleo-indicator.

Lixiviation of argillaceous rocks: Impact of oxidation degree states on organic compound mobilization

This work aims to study the influence of oxidation degree state which reached by organic matter included in argillaceous rocks on lixiviation and mobilization of compounds. Experimental lixiviation was carried out on two argillaceous rocks sampled in the surface deposit of the Andra laboratory (Bure, France). Molecular and spectroscopic characterizations of the organic matter extracts reveal two different oxidation levels reached by these samples: (i) a well preserved and (ii) an oxidized samples. Dissolved organic matter content and molecular investigation of sediment bitumen show that hydrophobic molecules (hydrocarbons) remain stable during lixiviation whereas specific polar compounds (alkanoic acids) are progressively removed by water. Moreover, occurrence of secondary alkanols with a molecular distribution similar to initial n-alkanes suggests that even in the well preserved sample, oxidation already occurs and that secondary alkanols can be used as specific markers for low intensity oxidation.

Williopsis californica, Williopsis saturnus, and Pachysolen tannophilus: novel microorganisms for stereoselective oxidation of secondary alcohols.

A screening of 416 microorganisms from different taxonomical groups (bacteria, actinomycetes, yeasts, and filamentous fungi) has been performed looking for active strains in the stereoselective oxidation of secondary alcohols. The working collection was composed of 71 bacterial strains, 45 actinomycetes, 59 yeasts, 60 basidiomycetes, 33 marine fungi, and 148 filamentous fungi. All microorganisms selected were mesophilic. Yeasts were the most active microbial group in the whole-cell-catalyzed oxidation. Williopsis californica, Williopsis saturnus, and Pachysolen tannophilus were the strains of greatest interest, both as growing cells and as resting cells. The oxidation of the alcohols takes place when cells are in the stationary growth phase (after 48 h of culture). These three strains are S-stereoselective for the oxidation of racemic secondary alkanols and show stereospecificity in the oxidation of menthol or neo-menthol, whereas iso-menthol is not oxidized. In the case of the 1-tetrahydronaphtol enantiomers, only the S-enantiomer is oxidized. The three strains were immobilized by entrapment using agarose and agar from algae of the Gracilaria genus. The agarose derivatives displayed significant improvement in the stereospecificity of the reactions.

An AIM study on the effects of position isomery in long-chain alkanols

The atomic and bond properties of secondary and tertiary alkanols given by R1R2COH(CH2)nCH3, where: R1=H,CH3; R2=H,Me,Et,Pr,Bu; and n=4, 5, 6, 7, 8, were obtained by employing the AIM theory on HF/6-31++G**//HF/6-31G* wave functions. It has been concluded that the properties of the methylene groups that are separated from the OH group by more than four bonds are practically equivalent to those of an n-alkane. Methylenes in δ disposition to the OH are different to those of an n-alkane, and display very similar properties along secondary and tertiary alkanols, that differ from those displayed in primary alkanols. Methylenes in γ are specific for each series of alkanols (primary, secondary, tertiary) and can be considered approximately transferable within each series. The same is true for the hydroxyl group and the methylenes that are α to it, when 2-alkanols are excluded in secondary and tertiary alkanols. Secondary and tertiary alkanols present different CH2β groups, that are approximately transferable within each series with the only exception of 2-decanol in secondary alkanols.

A new method for the determination of the absolute stereochemistry of aromatic and heteroaromatic alkanols using Mosher's esters

A list of the 1H NMR chemical shifts of the methoxy group of α-methoxy-α-(trifluoromethyl)phenylacetic acid (Mosher's) esters of α- and β-(hetero)aromatic secondary alkanols has been compiled. Methoxy groups which are orientated syn to the (hetero)aromatic group in Mosher's conformational model have lower chemical shift values than those in the anti-orientation.

Primary and secondary 5-(alkyloxy)thianthrenium perchlorates. Characterization with1H NMR spectroscopy, reactions with iodide and bromide ion, and thermal decomposition in solution

A series of 5-(alkyloxy)thianthrenium perchlorates has been made in which the alkyl group is primary (1a-1p) and secondary (2a-2g). Preparations were carried out by reaction of the corresponding alkanol with thianthrene cation radical perchlorate in CH2Cl2solution followed by precipitation of the perchlorate salt with dry ether.1H NMR spectroscopy reveals that the presence of a stereogenic center in the alkyl group causes inequivalence in the ordinarily paired protons (e.g., H-4, H-6) of the thianthrenium ring. Reaction of iodide and bromide ion with primary alkyl-group compounds (e.g., methyl, ethyl, propyl, butyl) gave the alkyl halide in very good yield and by a second-order kinetic displacement. The second product was thianthrene 5-oxide (ThO). Rate constants for some of these reactions are reported. Reaction of secondary alkyl group compounds (e.g., 2-propyl, 2-pentyl, 2-hexyl, and 3-hexyl) with iodide ion gave good yields of alkyl iodide but also increasing evidence for a side reaction at the sulfonium sulfur, leading to I2, thianthrene, and secondary alkanol. Decomposition of some compounds at 100°C in solution (acetonitrile or 1,2-dichloroethane) was studied and gave alkene(s) and ThO.Key words: thianthrene cation radical, 5-(alkyloxy)thianthrenium perchlorates.