Methyl Alkanoates Research Articles

Two-step separation for enriching phenols and esters from base-catalyzed depolymerization of sorghum stalk

Base-catalyzed depolymerization of sorghum stalk using Na2CO3, NaOH, and CaO was performed to afford methanol-soluble portion, and then extraction together with column chromatography was employed for enriching phenols and esters. The maximum total yield (ca. 53 wt%) of extract solutions 1–5 (ES1–ES5) was acquired at 280 °C with the equal mass of CaO and sorghum stalk. According to gas chromatograph/mass spectrometer analysis, phenols and esters are the predominate products. The phenols obtained from Na2CO3-catalyzed depolymerization of sorghum stalk mainly are methoxylphenols, while those obtained from NaOH and CaO-catalyzed depolymerization are dominated by alkylphenols, suggesting that NaOH or CaO plays an important role in demethoxylation during biomass depolymerization process. Phenols, methyl alkanoates/benzenecarboxylates, and dimethyl alkanedioates were roughly enriched into ES1, ES3, and ES5via sequential extraction with petroleum ether (PE), PE, and ethoxyethane, respectively. By the following column chromatographic separation of ES1 and ES3, alkylphenols and guaiacols were mainly enriched into PE/CS2 (4:3)-eluted fractions with maximum concentration of 92.2% and 92.1%, respectively. Saturated and unsaturated methyl alkanoates were isolated in concentration of near 100% by elution with PE/CS2 (9:1) and PE/CS2 (4:3), respectively. Extraction combined with column chromatography as two-step separation provides a promising approach for enriching phenols and esters from biomass-derived liquids.

Quantitative analysis of alkanoate and condensed arenes in the extracts from direct coal liquefaction residue by ultrasonication-assisted solvent extraction using alcohols

ABSTRACTShenmu-Fugu coal liquefaction residue (SFCLR) was ultrasonically extracted with methanol, ethanol, and isopropanol, respectively. Abundant of condensed arenes (CAs) were identified in the extracts using gas chromatography/mass spectrometer (GC/MS) by quantitative analysis, besides some alkanes and heteroatom-containing compounds. The most dominant CAs is benzo[ghi]perylene with its yield of 71.77 mg/g in isopropanol extract based on GC/MS analysis. Series of alkanoates were identified in the extracts from SFCLR with high yields. Interestingly, methyl alkanoates were identified in each of the three extracts, while ethyl and isopropyl alkanoates were only identified in the ethanol and isopropanol extracts, respectively. Accordingly, we presume that transesterification of methyl alkanoates with ethanol or isopropanol occurs during the ultrasonication-assisted solvent extraction.

Proton affinities and ion enthalpies

Proton affinities of a number of alkyl acetates (CH3–C(=O)–OR) and of methyl alkanoates (R–C(=O)–OCH3, R=H, alkyl) have been assembled from the literature or measured using the kinetic method. It was observed that the proton affinities for the isomeric species CH3–C(=O)–OR and R–C(=O)–OCH3 are almost identical, an unexpected result as the charge in these protonated ester molecules is largely at the keto carbon atom and so this site should be more sensitive to alkyl substitution. Analysis of the data, including those from lone pair ionisation and core-electron ionisation experiments available from the literature, indicate that after protonation, extensive charge relaxation (or polarisation) takes place (as is also the case, according to the literature, after core-electron ionisation). By contrast, after lone pair ionisation, which results in radical cations, such relaxation processes are relatively less extensive. As a consequence, changes in ion enthalpies of these protonated molecules follow more closely the changes in neutral enthalpies, compared with changes in enthalpies of the corresponding radical cations, formed by electron detachment. Preliminary analyses of published energetic data indicate that the above finding for organic esters may well be another example of a more general phenomenon.

Metal ion hydrocarbon bidentate bonding in alkyl acetates, methyl alkanoates, alcohols and 1-alkenes: a comparative study.

The relative affinity of the monovalent metal ions Li+, Na+, Cu+ and Ag+ towards a series of aliphatic alkyl acetates and some selected 1-alkenes (P) was examined using the kinetic method. A detailed analysis of the dissociation characteristics of a series of mixed metal-bound dimer ions of the type P1-M+-P2 and the evaluated proton affinities (PAs) of the monomers shows that the affinity of the cation towards long-chain alkyl acetates and alkenes (having a chain length ≤ C4) is markedly enhanced. In line with recent studies of nitriles, alcohols and methyl alkanoates, this is attributed to a bidentate interaction of the metal ion with the functional group or double bond and the aliphatic chain. In particular, the longer chain alkyl acetates, methyl alkanoates and alcohols show a remarkably similar behaviour with respect to silver ion hydrocarbon bonding. The Ag+ adducts of the alkyl acetates dissociate by loss of CH3COOH. This reaction becomes more pronounced at longer chain lengths, which points to metal ion bidentate formation in [Ag+···1-alkene] product ions having a long hydrocarbon chain. In the same vein, the heterodimers [1- hexene···Ag+···1-heptene] and [1- heptene···Ag+···1-octene] dissociate primarily into [Ag+···1-heptene] and [Ag+···1-octene] ions, respectively. Hydrocarbon bidentate formation in [Ag+···1-octene] also reveals itself by the reluctance of this ion to react with water in an ion trap, as opposed to [Ag+···1-hexene] which readily undergoes hydration.

Interaction of metal cations with functionalised hydrocarbons in the gas phase: further experimental evidence for solvation of metal ions by the hydrocarbon chain.

Relative affinity measurements of monovalent metal ions (= Li(+), Cu(+) and Ag(+)) towards aliphatic amines, alcohols and methyl alkanoates (P) have been performed using the kinetic method on the dissociation of metal bound dimer ions of the type P(1)-M(+)-P(2). It was found that the cations' affinity towards long chain (≥C(4) chain length) n- and s-alkylamines, n-alkanols and methyl n- alkanoates was unexpectedly enhanced. This is attributed to a bidentate interaction of the metal ion with the amine, alcohol or ester functional group and the aliphatic chain, paralleling earlier observations on metal bound nitriles. Methyl substitution at the functional group (s-alkylamines compared with n-alkylamines) serves to strengthen only the N•••M(+) bond, and this can be rationalized by the larger proton affinities of s-alkylamines compared to n-alkylamines. This substitution, however, has no effect on the metal ion-hydrocarbon bond. In contrast, methyl substitution remote from the functional group, as in iso-pentylamine, does lead to strengthening of the metal ion-hydrocarbon bond. The cuprous ion affinity of hexadecylamine, C(16)H(33)NH(2) was found to be as large as that for ethylenediamine (352 kJ mol(-1)), known to be a strong copper binding agent. It is argued that such a metal ion-hydrocarbon interaction does not occur in the metal bound dimers.

Primary alkanols: oxidative homocondensation in water and cross-condensation in methanol

Water was used as a reaction medium and a reagent in oxidation of primary alkanols to dimeric esters and alkanoic acids using either molecular bromine or a hydrogen peroxide—hydrobromic acid mixture as the oxidants. The similar reaction in methanol produced methyl alkanoates.

Mixing thermodynamic properties of ester-containing solutions: A study on the ternary (methyl alkanoate (pentanoate and methanoate) + methanol) and the corresponding binaries. New contributions to the (ester + ester) interactions

This work studies the volumetric (VmE) and energetic (HmE) properties resulting from the mixing processes of binary systems and the corresponding ternary of two methyl esters (methanoate and pentanoate) with methanol. The three binaries produce net endothermic mixing effects, with important energetic interactions, with maximum values of HmE≅400J⋅mol−1, for the (ester+ester) system. This produces expansive effects VmE>0, but the binaries of the (methyl esters+methanol) give rise to contractions VmE<0, due to the formation of molecular aggregates. The endothermicity in the mixing processes is a net effect which is justified by interactions of different nature, especially dipolar interactions and hydrogen bonds of the substances involved. The overall results in the ternary respond to the individual contributions of the binaries and the increment due to the simultaneous presence of the three compounds in the solution. The experimental results are correlated with our own model that gives a good representation of the properties of the solutions studied. The analysis of the behavior of the solutions is reinforced by spectral data obtained by 1H NMR, supporting the structural model established. The application of UNIFAC to estimate the HmE in the ternary improves when one takes into account the individual contributions of the (ester+ester) interactions whose parameter are predetermined.

Separation and identification of organic compounds from thermally dissolved Shengli lignite in a methanol/benzene mixed solvent

Thermal dissolution of Shengli lignite was conducted in a methanol/benzene mixed solvent at 240oC for 1 h. The soluble fraction was sequentially eluted with petroleum ether (PE) and carbon disulfide (CDS)/ PE mixed solvents with increased CDS to PE ratio through a silica gel-packed column. A series of normal alkanes, polycyclic aromatics, methyl alkanoates, alkanoic acids, and fatty acid amides were enriched to large extents and 6-hydroxy-7-isopropyl-1,1,4a-trimethyl-2,3,4,4a,10, 10a-hexahydrophenanthren-9(1H)-one was successfully separated with high purity by the column chromatography.

ChemInform Abstract: Iron‐Catalyzed Hydrosilylation of Esters.

AbstractIn the presence of piano‐stool‐type iron catalyst IPC, under visible‐light activation and in the absence of a solvent, methyl alkanoates are converted to the corresponding alcohols.

Hydrothermal alteration of sedimentary organic matter in the presence and absence of hydrogen to tar then oil

Hydrothermal alteration (hydrous pyrolysis) experiments, in the absence and presence of H 2 (reductive), were conducted on organic matter from marine and lacustrine sediments. The experiments were carried out at discrete temperatures from 150 °C to 350 °C to assess the yields and compositions of the bitumen (tar) formed and subsequently at higher temperatures the oil generated. The yield of bitumen was observed to increase with increasing temperatures. Under hydrous pyrolysis conditions with hydrogen, the yield increases by an order of magnitude and immature lacustrine organic matter shows the highest yield. Bitumen, the extractable organic matter at temperatures below 250–300 °C, contains mainly polar compounds, an unresolved complex mixture (UCM) of branched and cyclic compounds, with low amounts of saturated hydrocarbons. The polar compounds include n-alkanoic acids, n-alkanedioic acids, n-alkanols, isoprenoid ketones and methyl alkanoates. At temperatures above 300 °C, the bitumens transform into petroleum products with saturated hydrocarbons ( n-alkanes and biomarkers) and UCM as the major components (>95% of total yield). The degree of maturation of the generated oil increases with increasing temperature under both pyrolysis conditions to full maturity at >350 °C. Although, the bitumen yield is much higher under conditions with added hydrogen, the maturity of the generated oil is lower than with just hydrous pyrolysis.

Occurrences and distributions of branched alkylbenzenes in the Dongsheng sedimentary uranium ore deposits, China

A series of branched alkylbenzene ranging from C 15 to C 19 with several isomers (2–5) at each carbon number were identified in sediments from the Dongsheng sedimentary uranium ore deposits, Ordos Basin, China. The distribution patterns of the branched alkylbenzenes show significant differences in the sample extracts. The branched alkylbenzenes from organic-rich argillites and coals range from C 15 to C 19 homologues, in which the C 17 or C 18 dominated. On the other hand, the C 19 branched alkylbenzenes dominated in the sandstone/siltstone extracts. The obvious differences of the branched alkylbenzene distributions between the uranium-host sandstones/siltstones and the interbedded barren organic-rich mudstones/coals probably indicate their potential use as biological markers associated with particular depositional environments and/or maturity diagenetic processes. Possible origins for these branched alkylbenzenes include interaction of simple aromatic compounds with, or cyclization and aromatization reactions of, these linear lipid precursors such as fatty acids, methyl alkanoates, wax esters or alkanes/alkenes that occur naturally in carbonaceous sediments. The possible simple aromatic compounds may include substituted benzenes, functionalized compounds such as phenols that are bound to kerogen at the benzyl position, and phenols that are decomposition products derived from aquatic and terrestrial sources. The distributions of methyl alkanoates and n-alkanes were found to be different between organic-rich mudstone/coal and sandstone/siltstone. From this result, it can be concluded that such differences of the alkylbenzene distributions were mainly resulting from the differences of organic precursors, although maturity effect and radiolytic alteration cannot be completely excluded.

Isolation and Identification of Methyl Alkanoates from Lingwu Coal

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTIsolation and Identification of Methyl Alkanoates from Lingwu CoalZi-Wu Liu†‡, Xian-Yong Wei*†§, Zhi-Min Zong†, Jin-Na Li†, Jia-Qi Xue∥, Xue-Feng Chen∥, and Fei-Jian Chen†View Author Information† Key Laboratory of Coal Processing and Efficient Utilization (Ministry of Education), China University of Mining and Technology, Xuzhou 221008, Jiangsu, China‡ School of Chemistry and Chemical Engineering, South China University of Technology, Wushan 381, Guangzhou 510640, Guangdong, China§ Hubei Coal Conversion and New Carbon Materials Laboratory, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China∥ Xuzhou Number 1 Middle School, Xuzhou 221002, Jiangsu, China*To whom correspondence should be addressed. Telephone: +86-(516)-83884399. E-mail: [email protected]Cite this: Energy Fuels 2010, 24, 4, 2784–2786Publication Date (Web):February 8, 2010Publication History Received12 October 2009Revised30 January 2010Published online8 February 2010Published inissue 15 April 2010https://doi.org/10.1021/ef9011627Copyright © 2010 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views297Altmetric-Citations19LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (825 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Alkyls,Coal,Crystals,Organic compounds,Solvents Get e-Alerts

Direct Liquefaction of Corn Stalk in Sub- and Supercritical Methanol

Corn stalk was liquefied in methanol under sub/supercritical states and the reaction mixture was extracted with methanol, acetone, and acetone/CS2 (1:1 vol/vol) mixed solvent sequentially. The effects of temperature, time, and the ratio of corn stalk to solvent on the yields of extracts and residue were investigated. The extracts were analyzed with a gas chromatography/mass spectrometer. The results show that corn stalk can be liquefied in sub- and supercritical methanol and over 98% of corn stalk is converted at 300°C and 1.5 h. Benzene-ring-containing compounds, and methyl alkanoates are the dominant constituents of the methanol-extractable fractions from corn stalk liquefied with methanol.

Identification and biosynthesis of tropone derivatives and sulfur volatiles produced by bacteria of the marine Roseobacter clade

Bacteria of the Roseobacter clade are abundant marine bacteria and are important contributors to the global sulfur cycle. The volatiles produced by two of its members, Phaeobacter gallaeciensis and Oceanibulbus indolifex, were analyzed to investigate whether the released compounds are derived from sulfur metabolism, and which biosynthetic pathways are involved in their formation. Both bacteria emitted different sulfides and thioesters, including new natural compounds such as S-methyl phenylethanethioate (16) and butyl methanesulfonate (21). The S-methyl alkanoates were identified by comparison with standards that were synthesized from the respective methyl alkanoates by a new method using an easily prepared aluminium/sulfur reagent. Phaeobacter gallaeciensis is also able to produce tropone (37) in large amounts. Its biosynthesis was investigated by various feeding experiments, showing that 37 is formed via a deviation of the phenylacetate catabolism. The unstable tropone hydrate 42 was identified as an intermediate of the tropone biosynthesis that was also released together with tropolone (38).

Impact of temperature on long chain diol and mid-chain hydroxy methyl alkanoate composition in Proboscia diatoms: Results from culture and field studies

Long chain 1,14-diols and 12-hydroxy methyl alkanoates are biomarker lipids for Proboscia diatoms and occur widely in Quaternary sediments. To determine the effect of temperature on the lipid composition of these algae, a new Proboscia sp. culture grown at 8 °C and Proboscia indica cultures grown at 18, 21, 24 and 27 °C were examined. The results were combined with lipid data from a P. indica culture and a Proboscia alata culture, grown at 20 and 2 °C, respectively, from previous studies. The data showed a strong relationship between long chain diol and 12-hydroxy methyl alkanoate composition and growth temperature, i.e. the chain length increases and the degree of unsaturation of long chain 1,14-diols decreases with increasing growth temperature. To determine the effect of temperature on Proboscia lipid compositions in natural environments, we also analyzed fossil long chain 1,14-diols and 12-hydroxy methyl alkanoates in surface sediments derived from Proboscia diatoms living in the water column of the eastern South Atlantic. The results indicate a significant relationship between sea surface temperature and chain length distribution of saturated long chain diols, but also suggest that the relative abundances of unsaturated long chain diols and 12-hydroxy methyl alkanoates in sediments are predominantly determined by factors other than temperature.

Furanone derivatives as quorum-sensing antagonists of Pseudomonas aeruginosa

The biofilm formation of Pseudomonas aeruginosa, an opportunistic human pathogen, is developed by cell-to-cell signaling, so-called quorum sensing (QS). To control the biofilm formation, we designed and synthesized new QS inhibitors of P. aeruginosa based on the structure of the previously known QS inhibitor, furanone. Newly synthesized compounds were a series of analogs of (5-oxo-2,5-dihydrofuran-3-yl)methyl alkanoate, and the structures of all six synthesized compounds was confirmed by NMR and GC/MS analyses. These new QS inhibitor candidates could remarkably inhibit both Pseudomonas QS signaling and biofilm formation, which were assayed by using the recombinant reporter system and flow cell confocal microscopy. The degree of QS inhibition by these new inhibitors varied from 20% to 90%. For the profound understanding about inhibition mechanism, we tried to estimate the binding energy between QS receptor, LasR, and our inhibitors from the in silico modeling system. The predicted binding pattern from the modeling system and our experimental data about QS inhibition were in good agreement. From these results, we suggest a new approach to develop the QS inhibitors and biofilm control agents based on structural modeling.

Synthesis of chiral β 2,2,3-3-amino-2-hydroxyalkanoates and 3-alkyl-3-hydroxy-β-lactams by double asymmetric induction

Reactions of chiral (2 S)-enolates of dioxolan-4-ones, derived from lactic, mandelic, and phenyllactic acids, with aliphatic ( S S )- and ( S R )- tert-butylsulfinyl aldimines afforded conformationally restrained C2-disubstituted N, O-orthogonally protected 3-amino-2-hydroxyalkanoates in the form of N-sulfinyl protected 1′-aminodioxolan-4-ones. The product distribution showed that there is significant kinetic selectivity, due to the presence of ‘matched’ and ‘mismatched’ components, between the ( S)- or ( R)- tert-butylsulfinyl aldimines and the (2 S)-enolates of the 1,3-dioxolan-4-ones. Selective methoxide-induced removal of the acetal group of the N-sulfinyl-1′-aminodioxolanones yielded the corresponding N-sulfinyl protected methyl alkanoates. In addition, the selective acid-induced removal of the sulfinyl group of the N-sulfinyl-1′-aminodioxolanones provided the corresponding N-unprotected 1′-aminodioxolanones, whose base-induced cyclization afforded the corresponding β-lactams.

Organic geochemistry of the Dongsheng sedimentary uranium ore deposits, China

Organic matter (OM) associated with the Dongsheng sedimentary U ore hosting sandstone/siltstone was characterized by Rock-Eval, gas chromatography–mass spectrometry and stable C isotope analysis and compared to other OM in the sandstone/siltstone interbedded organic matter-rich strata. The OM in all of the analyzed samples is Type III with Ro less than 0.6%, indicating that the OM associated with these U ore deposits can be classified as a poor hydrocarbon source potential for oil and gas. n-Alkanes in the organic-rich strata are characterized by a higher relative abundance of high-molecular-weight (HMW) homologues and are dominated by C 25, C 27 or C 29 with distinct odd-to-even C number predominances from C 23 to C 29. In contrast, in the sandstone/siltstone samples, the n-alkanes have a higher relative abundance of medium-molecular-weight homologues and are dominated by C 22 with no or only slight odd-to-even C number predominances from C 23 to C 29. Methyl alkanoates in the sandstone/siltstone extracts range from C 14 to C 30, maximizing at C 16, with a strong even C number predominance, but in the organic-rich layers the HMW homologues are higher, maximizing at C 24, C 26 or C 28, also with an even predominance above C 22. n-Alkanes in the sandstone/siltstone sequence are significantly depleted in 13C relative to n-alkanes in most of the organic-rich strata. Diasterenes, ββ-hopanes and hopenes are present in nearly all the organic-rich sediments but in the sandstone/siltstone samples they occur as the geologically mature isomers. All the results indicate that the OM in the Dongsheng U ore body is derived from different kinds of source materials. The organic compounds in the organic-rich strata are mainly terrestrial, whereas, in the sand/siltstones, they are derived mainly from aquatic biota. Similar distribution patterns and consistent δ 13C variations between n-alkanes and methyl alkanoates in corresponding samples suggest they are derived from the same precursors. The OM in the organic-rich strata does not appear to have a direct role in the precipitation of the U ore in the sandstone, but an indirect role cannot be excluded. The OM in the U hosting sandstone shows a relatively low hydrogen index, presumably due to oxidation or radiolytic damage.

Seasonal and spatial variation in the sources and fluxes of long chain diols and mid-chain hydroxy methyl alkanoates in the Arabian Sea

Long chain 1,14-diols and 12-hydroxy methyl alkanoates may be useful indicators for high-nutrient conditions as their inferred sources, diatoms belonging to the genus Proboscia, are often abundant in upwelling regions. In order to test this hypothesis, the lipids of three different Proboscia species in culture were determined and the fluxes of different long chain diol isomers and mid-chain hydroxy methyl alkanoates in the Arabian Sea were studied. The culture studies showed that long chain 1,14-diols and 12-hydroxy methyl alkanoates are indeed major lipids in Proboscia indica, Proboscia inermis and Proboscia alata. Time-series sediment trap data from the Arabian Sea showed increased fluxes of long chain 1,14-diols and 12-hydroxy methyl alkanoates in periods of upwelling and low fluxes for the rest of the year. High fluxes were found primarily at stations in the upwelling area close to the coast, whereas at a station located 590 km off the coast of Oman fluxes were substantially lower. These results show that long chain 1,14-diols and 12-hydroxy methyl alkanoates can be used as proxies for upwelling conditions. Flux patterns of 1,15-diols did not, however, resemble those of 1,14-diols: 1,15-diols reached maximum flux earlier than 1,14-diols, annual flux of 1,15-diols was much lower than 1,14-diols and upwelling did not seem to affect 1,15-diol flux values. This agrees with the idea that the Eustigmatophytes rather than Proboscia spp. should be considered as the major source of 1,15-diols.

Organic compound tracers of fine soil and sand particles during summer in the metropolitan area of Riyadh, Saudi Arabia

Soil and sand fine particles, which may be resuspended as fine dust in the atmosphere, contain a variety of anthropogenic and natural organic components. Samples of fine soil and sand particles (sieved to <125 μM) were collected from the Riyadh area in the summer of 2003 and extracted with a mixture of dichloromethane and methanol (3:1, v:v). The derivatized total extracts were analyzed by gas chromatography–mass spectrometry in order to characterize the composition and sources of the organic components. Both anthropogenic and natural biogenic inputs were the major sources of the organic compounds in these extracts. Discarded plastics and vehicular emission products were the major anthropogenic sources in the fine particles from populated areas of the city. Their tracers were plasticizers, UCM, n-alkanes, hopanes and traces of steranes. Vegetation was the major natural source of organic compounds in samples from outside Riyadh and included n-alkanols, n-alkanoic acids, n-alkanes, methyl alkanoates, sterols and triterpenoids. Carbohydrates had high concentrations (42–54%) in all samples and indicate sources from decomposition of cellulose and/or the presence of viable microbiota such as bacteria and fungi. The results were also compared with the data obtained in winter 2002 and showed that anthropogenic inputs were higher in summer than in winter, whereas the opposite trend was observed for natural inputs.