Bio-oil generated by the fast pyrolysis of biomass is an unstable material, undergoing chemical and physical transformations as the oil ages at room temperature. In this study, electrostatic precipitator. (ESP) pine wood-derived bio-oil, which contains less water and does not undergo phase-separation upon aging, was characterized following accelerated aging. Bulk oil properties (percent water and viscosity) were found to increase in ways similar to conventional bio-oils. The imaged and-aged bib-oil samples were characterized by gel permeation chromatography (GPC), solvent fractionation, solution C-13 NMR, gas chromatography/mass spectrometry (GC/MS), and chip-based nanoelectrospray ionization, liquid chromatography, quadrupole time-of-flight (nanoESI-LC-QTOF) MS/MS. Using the formation of the silyated derivatives to extend the range of detectable compounds, GC/MS analysis was used to identify specific compounds that showed:, elevated reactivity, extending the understanding of reactivity characteristics beyond the known reactivity of aldehydes and Some aromatics to distinguishing the reactivity of ring-conjugated aromatics and certain polyhydroxylated benzenes; specifically the 1,3-di-, 1,2,3-tri-, and 1,2,4-trihydroxy substituted compounds. To explain the enhanced reactivity of these compounds, we propose acid-catalyzed formation of quinone methides, as important intermediates. Additionally, we find significant changes to the composition of mono- and disaccharides, where specific monosaccharides (arabinose, xylose, and glucose) increased in concentration With aging and high reactivity was observed for certain sugars with furano-ring mass spectral characteristics. In contrast, we also found that three anhydrosugars (levoglucosan, mannosan, and galactosan) were largely stable-with respect to aging. High mass resolution nanoESI-LC/MS/MS analyses of peracetylated samples permitted the analysis and chromatographic separation of both lignin and carbohydrate-derived oil components and were used for the identification of a putative formaldehyde trihydroxybenzene dieter. This work provides further insights into chemically specific entities and the processes responsible for bio-oil aging.

Determination of the molecular composition of biofuels is critical to process development. Because biofuels, such as pyrolysis oil, contain hundreds of compounds, quantitative determination of the mixtures is a formidable task and is often not necessary for routine development work. 13C and 1H nuclear magnetic resonance (NMR) offer a reasonable trade-off between functional group identification and analytical measurement effort. However, accuracy depends upon selection of chemical-shift regions, baseline compensation, and correction for incomplete longitudinal relaxation effects. We propose chemical-shift assignments and T1 correction factors based on 13C and 1H NMR measurements of over 50 compounds that have been previously identified in pyrolysis oils and several plant natural products, especially terpenes. The results are intended to allow for a semiquantitative assessment of molecular composition of bio-oils on a time scale of 1−8 h to provide feedback for process development.

Qualitative and quantitative analyses were carried out on vegetative tissues of potato (Solanum tuberosum cv. “Katahdin”) in search of natural products thought to play a role in tuber induction. Tissues were obtained from plants initially grown in a growth chamber under noninducing conditions (30°C day and 28°C night with an 18-h photoperiod), and then half of the plants were moved to inducing chambers (28°C day and 13°C night with a 10-h photoperiod) for 10 days prior to tissue harvest. Plants from each chamber were then harvested at 2-day intervals for 10 days, separated into above- and belowground portions, and the lyophilized tissues were extracted and subjected to rigorous purification and separation using high-performance liquid chromatography. This was followed by identification and quantification using combined gas chromatography-mass spectrometry. Compounds isolated and identified included gibberellic acid; cytokinins cis-zeatin riboside, trans-zeatin, trans-zeatin riboside, and isopentenyladenine; and jasmonates jasmonic acid, tuberonic acid and its methyl ester, methyl 7-isocucurbate, and 9,10-dihydromethyljasmonate. Methyl 7-isocucurbate and 9,10-dihydromethyljasmonate were detected for the first time in potato tissue as endogenous compounds. Cytokinin and jasmonate levels generally increased under inducing conditions, whereas gibberellic acid levels declined progressively during the 10-day sampling period. Only gibberellic acid, jasmonic acid, and cis-zeatin riboside levels were significantly influenced by induction.

A size selective approach to improving selectivity in semiconducting metal oxides (SMO) sensors was obtained by tailoring the architecture of WO(3) powders. The key for achieving high selectivity is based on using a dual sensor configuration where the response on a porous WO(3) powder sensor was compared to the response on a nonporous WO(3) powder sensor. Detection selectivity between methanol and dimethyl methylphosphonate (DMMP) is obtained because the access of a gas molecule in the interior pore structure of WO(3) is size dependent leading to a size dependant magnitude change in the conductivity of SMO sensor.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIsolation of Betulin and Rearrangement to Allobetulin. A Biomimetic Natural Product SynthesisBrian Green , Michael D. Bentley , Bong Y. Chung , Nicholas G. Lynch , and Bruce L. Jensen View Author Information Department of Chemistry, University of Maine, Orono, ME 04473Cite this: J. Chem. Educ. 2007, 84, 12, 1985Publication Date (Web):December 1, 2007Publication History Received3 August 2009Published online1 December 2007Published inissue 1 December 2007https://pubs.acs.org/doi/10.1021/ed084p1985https://doi.org/10.1021/ed084p1985research-articleACS PublicationsRequest reuse permissionsArticle Views2787Altmetric-Citations39LEARN 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 InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Cancer,Cyclization,Pharmaceuticals,Rearrangement,Triterpenes Get e-Alerts

The photodecomposition of dimethyl methylphosphonate (DMMP) and trimethyl phosphate (TMP) adsorbed on monoclinic WO3 powders when irradiated by ultraviolet light (UV) in air, oxygen, and under evacuation was investigated using infrared spectroscopy (IR). The IR spectra show that DMMP decomposes into methyl phosphonate upon exposure to 254 nm UV for 2 h at room temperature in air. The same decomposition of DMMP occurs only at temperatures above 300°C without UV illumination. TMP differs from DMMP in that the photodecomposition product is not the same as the decomposition product obtained by heating above 300°C. Thermal decomposition leads to formation of a phosphate on the surface, whereas photodecomposition leads to the same adsorbed methyl phosphonate as found for the thermal or photodecomposition of DMMP. Since TMP does not contain a P-CH3 bond, the formation of a methyl phosphonate on the surface after UV illumination involves a mechanism where CH3 groups migrate from the methoxy group to the phosphorous central atom. No decomposition is observed at room temperature when DMMP or TMP adsorbed on WO3 is irradiated under vacuum or in nitrogen atmosphere. Therefore, the photodecomposition of either DMMP or TMP adsorbed on WO3 at room temperature does not involve a reaction with the lattice oxygen but rather a reaction with the oxygen radicals produced by the decomposition of ozone.

A concise synthesis of (±)-cuparene via Grignard, trimethylaluminum and dimethyltitanium dichloride (Reetz Alkylation) reactions to form the quaternary centers of (±)-cuparene is reported.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular Mechanics and Variable-Temperature 1H NMR Studies on N,N-Diethyl-m-toluamide. An Undergraduate NMR and Molecular Modeling ExperimentBruce L. Jensen and Raymond C. Fort Jr.View Author Information Department of Chemistry, University of Maine, Orono, ME 04469Cite this: J. Chem. Educ. 2001, 78, 4, 538Publication Date (Web):April 1, 2001Publication History Received3 August 2009Published online1 April 2001Published inissue 1 April 2001https://pubs.acs.org/doi/10.1021/ed078p538https://doi.org/10.1021/ed078p538research-articleACS PublicationsRequest reuse permissionsArticle Views2393Altmetric-Citations7LEARN 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 InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Amides,Conformation,Ethyl groups,Molecular modeling,Nuclear magnetic resonance spectroscopy Get e-Alerts

Dehydration of 1-substituted-1,2-tetralindiols with zinc iodide afforded the corresponding 2-tetralones in excellent yields. This procedure was found to be superior to the more conventional BF3-catalyzed rearrangement of 1-substituted-1,2-epoxytetralins.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCyclization of the Monoterpene Citronellal to Isopulegol: A Biomimetic Natural Product SynthesisBruce L. Jensen , Ahmed Malkawi , and Vanessa McGowan View Author Information Department of Chemistry, University of Maine, Orono, ME 04469Cite this: J. Chem. Educ. 2000, 77, 11, 1474Publication Date (Web):November 1, 2000Publication History Received3 August 2009Published online1 November 2000Published inissue 1 November 2000https://pubs.acs.org/doi/10.1021/ed077p1474https://doi.org/10.1021/ed077p1474research-articleACS PublicationsRequest reuse permissionsArticle Views2159Altmetric-Citations6LEARN 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 InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Anions,Carbene compounds,Cyclization,Pharmaceuticals,Substitution reactions Get e-Alerts

The chiral allylsilylene prepared from (-)-10-phenylpinanediol reacts with chiral a-alkoxy aldehydes in the presence of stannic chloride to afford homoallylic alcohols with diastereofacial selectivity ratios as high as 100:0. The results are consistent with attack of the allylsilylene on the less hindered face of the chelated intermediate. Our preliminary studies on several silylenes prepared from bicyclo[3.1.1] systems revealed that substituent effects on the chiral auxiliary and the silicon atom play an important role in the selectivity of these unique compounds.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStudies of the ketone obtained from the ozonolysis of vitamin D. Molecular mechanics calculations for it and related hydrindanonesPaul E. Peterson, Rebecca L. Breedlove Leffew, and Bruce L. JensenCite this: J. Org. Chem. 1986, 51, 11, 1948–1954Publication Date (Print):May 1, 1986Publication History Published online1 May 2002Published inissue 1 May 1986https://pubs.acs.org/doi/10.1021/jo00361a002https://doi.org/10.1021/jo00361a002research-articleACS PublicationsRequest reuse permissionsArticle Views455Altmetric-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 InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRates and products of the reaction of a .beta.,.beta.-dichlorobenzylic alcohol and its derivatives in trifluoroacetic acid-sulfuric acid. A 1,2-chlorine shift giving an .alpha.-chloro ketoneBruce L. Jensen and Paul E. PetersonCite this: J. Org. Chem. 1977, 42, 25, 4052–4055Publication Date (Print):December 1, 1977Publication History Published online1 May 2002Published inissue 1 December 1977https://pubs.acs.org/doi/10.1021/jo00445a013https://doi.org/10.1021/jo00445a013research-articleACS PublicationsRequest reuse permissionsArticle Views43Altmetric-Citations3LEARN 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 InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAcid hydrolysis products of DDD and DDT precursorsBruce L. Jensen and Raymond E. CounsellCite this: J. Org. Chem. 1973, 38, 4, 835–838Publication Date (Print):February 1, 1973Publication History Published online1 May 2002Published inissue 1 February 1973https://pubs.acs.org/doi/10.1021/jo00944a056https://doi.org/10.1021/jo00944a056research-articleACS PublicationsRequest reuse permissionsArticle Views72Altmetric-Citations4LEARN 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 InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

The chemistry of DDT and DDD derivatives was explored by studying the steric and electronic effects on the hydrolysis of a variety of substituted diphenylacetaldehyde ethylene glycol cyclic acetals. This investigation demonstrated that ortho substituents, p-nitro, and p-methoxy groups affect the product distribution in different ways. The mechanistic details of this work are discussed.

Journal of Heterocyclic ChemistryVolume 7, Issue 5 p. 1077-1081 Article Synthesis and photolysis of kreysiginone Robert K. Harmon, Robert K. Harmon Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49001Search for more papers by this authorBruce L. Jensen, Bruce L. Jensen Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49001Search for more papers by this author Robert K. Harmon, Robert K. Harmon Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49001Search for more papers by this authorBruce L. Jensen, Bruce L. Jensen Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49001Search for more papers by this author First published: October 1970 https://doi.org/10.1002/jhet.5570070512Citations: 9AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume7, Issue5October 1970Pages 1077-1081 RelatedInformation

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of substituted 1-styryl-3,4-dihydroisoquinolinesRobert E. Harmon, Bruce L. Jensen, Surendra Kumar Gupta, and John D. NelsonCite this: J. Org. Chem. 1970, 35, 3, 825–827Publication Date (Print):March 1, 1970Publication History Published online1 May 2002Published inissue 1 March 1970https://pubs.acs.org/doi/10.1021/jo00828a066https://doi.org/10.1021/jo00828a066research-articleACS PublicationsRequest reuse permissionsArticle Views111Altmetric-Citations12LEARN 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 InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts