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Aliphatic Acids (aliphatic + acid)
Selected AbstractsAn Efficient Method for the Synthesis of Aliphatic Acids Using Microwaves.CHEMINFORM, Issue 47 2005George Bratulescu Abstract For Abstract see ChemInform Abstract in Full Text. [source] Character impact odorants from wild mushroom (Lactarius hatsudake) used in Japanese traditional foodFLAVOUR AND FRAGRANCE JOURNAL, Issue 4 2010Mitsuo Miyazawa Abstract The components of the volatile oil from wild mushroom (Lactarius hatsudake), used in Japanese traditional food, were analysed and quantified for the first time by capillary GC and GC,MS. Seventy-six components were separated from the oil and of these 71 components were identified. The main components of the oil were oxidized sesquiterpenes [cis -isolongifolanone (624.9,,g/100,g), , -cedrene epoxide (578.7,,g/100,g), humulene epoxide III (453.9,,g/100,g), clovane (425.4,,g/100,g)], aliphatic acids [linoleic acid (585.9,,g/100,g) and palmitoleic acid (333.3,,g/100,g)]. Odour evaluation of the volatile oil from L. hatsudake was also carried out using GC,MS/olfactometry (GC,MS/O) and aroma extract dilution analysis (AEDA), from which it was found that hexanal, 4-dehydroviridiflorol, myliol and phenylacetaldehyde seem to contribute to the green, spicy and sweet odour of L. hatsudake. Copyright © 2010 John Wiley & Sons, Ltd. [source] Benzene polycarboxylic acids,A ubiquitous class of compounds in soilsJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 5 2010Ludwig Haumaier Abstract Black carbon (BC) occurs ubiquitously in the environment. Its oxidation in the laboratory yields a suite of benzene polycarboxylic acids (BPCAs), suggesting similar oxidation products in soils. Since only for a few soils the occurrence of BPCAs in the free form has been documented, screening for them in a broad range of contrasting soils was conducted. They were extracted from soil samples with 0.5 M NaOH and quantified using gas chromatography,mass spectrometry. As expected, BPCAs turned out to be as ubiquitous as BC. They were detected not only in every soil sample investigated so far, but also in samples from drill cores up to a depth of 10 m and in recently deposited calcareous tufa. The concentrations covered a range similar to that of some phenolic acids. The range exceeded those reported for low-molecular-weight aliphatic acids or simple sugars in soils. The distribution of BPCAs in soil profiles indicated a considerable potential of translocation within, and export from, soil, in particular of benzene hexacarboxylic (mellitic) acid. Mellitic acid may therefore be present in almost any geochemical sample affected by seepage water from soils. Its high water solubility and strong metal-complexing ability suggest it may be involved in metal-transport processes, at least on geological timescales. [source] Potential mechanism for detection by Apis mellifera of the parasitic mite Varroa destructor inside sealed brood cellsPHYSIOLOGICAL ENTOMOLOGY, Issue 3 2002Caroline Martin Abstract The parasitic mite Varroa destructor Anderson & Trueman is a major pest of the honeybee Apis mellifera L. throughout the world. Chemical agents currently used for mite control leave contaminating residues and promote pesticide resistance. As an alternative means of control, it would be useful to identify natural substances enabling bees to detect Varroa inside brood cells. These substances could then be used to trigger mite hygienic behaviour by bees. In this study several techniques were used to screen substances that might allow detection of infested brood cells by bees. Gas chromatography-mass spectrometry analysis was performed on substances extracted in dichloromethane from the contents of brood cells. Solid phase microextraction and solid injection were performed on substances obtained from living and dead Varroa, respectively. Electroantennography was performed to assess the sensitivity of olfactory receptors in bee antennae to some of these substances. Principal component analysis based on proportions of cuticular substances allowed discrimination between bees and other cell contents. Foundress Varroa exhibited the greatest dissimilarity to healthy pupae that were used as controls. Immature Varroa and faecal material were intermediate. High molecular weight compounds, mainly dimethylalkanes, were proportionally the most characteristic components of foundress Varroa. This finding suggests that these compounds would be the most apt to induce uncapping of cells infested by Varroa. Solid-phase microextraction and solid injection demonstrated the presence of aliphatic acids, esters, and one alcohol, eicosenol, in Varroa. Electroantennographic recordings showed that mite-resistant bees were more responsive to some acids and one ester. We speculate that these compounds may be involved in recognition of living Varroa by honeybees. [source] Identification of feeding attractants in oak sap for adults of two nymphalid butterflies, Kaniska canace and Vanessa indicaPHYSIOLOGICAL ENTOMOLOGY, Issue 3 2000Hisashi Ômura Abstract The active compounds of oak-sap odour in attracting adults of two butterflies, Kaniska canace (L.) and Vanessa indica (Herbst) (Lepidoptera: Nymphalidae), were identified by chemical analyses, electroantennogram (EAG) and two behavioural assays: proboscis extension reflex (PER) and attraction to artificial tree models. Fourteen compounds were identified from two sap samples collected in 1997 and 1998, of which the major volatiles were ethanol and acetic acid (, 900 p.p.m. and 500 p.p.m. in sap, respectively). However, the chemical composition of the minor volatiles varied considerably between the two samples. Among 13 chemicals tested, V. indica showed strong PER to five aliphatic acids (acetic, propionic, butyric, isobutyric and isovaleric), 2-methylpropan-1-ol and 3-hydroxybutan-2-one, whereas the PER-active compounds for K. canace were these seven compounds and also ethanol, 3-methylbutan-1-ol and 1-hydroxypropan-2-one. In two-choice behavioural bioassays, the model scented with a sap-odour mimic, which was an aqueous mixture of the PER-active compounds, was more attractive to the two butterflies than an unscented control. These results demonstrated that the sap odour stimulates foraging behaviour of the butterfly. Although EAG responses of both butterflies to 3-methylbutan-1-ol and that of V. indica to 2-methylpropan-1-ol were positively dose-dependent, responses to other compounds were not strong and not dose-dependent at 1,100 ,g doses. These EAG responsiveness suggests that the olfactory receptors for these compounds might be few in the antenna and that the butterflies have enough olfactory sensitivity to the dose of 1 ,g. [source] Torque-rheometry investigation of model transreactions involving condensation polymers.POLYMER ENGINEERING & SCIENCE, Issue 2 2006The chemical transformations taking place when poly(ethylene terephthalate) (PET) or poly(ethylene naphthalate) (PEN) are blended in the melt with different low molar mass substances containing hydroxyl, carboxyl, or amine functional groups have been investigated as models of the transreactions, undergone by the polyesters in reactive blending operations. The polyester molecular weight changes caused by the alcoholysis, acidolysis, aminolysis, and esterolysis reactions have been monitored by torque-rheometry, using a Brabender Plasticorder static mixer. The degradation of the polyesters by hydrolysis was also studied, under similar conditions, by the addition of a water-releasing substance (wet polyamide-6), and was shown to occur quite rapidly, although most of the added water was lost by flash vaporization caused by the high temperature of the polyester melt. It has been shown that the rate constants of the reactions leading to breakage of the inner ester bonds of the polyester macromolecules decrease in the following order: aminolysis (with aliphatic amines, either primary and secondary) > alcoholysis (with aliphatic alcohols) , hydrolysis > acidolysis (with aromatic acids) , acidolysis (with aliphatic acids) , aminolysis (with aromatic amines) > alcoholysis (with phenols) , esterolysis. POLYM. ENG. SCI. 46:139,152, 2006. © 2005 Society of Plastics Engineers [source] A Broad Diversity of Volatile Carboxylic Acids, Released by a Bacterial Aminoacylase from Axilla Secretions, as Candidate Molecules for the Determination of Human-Body Odor TypeCHEMISTRY & BIODIVERSITY, Issue 1 2006Andreas Natsch Abstract Human body odor is to a large part determined by secretions of glands in the axillary regions. Two key odoriferous principles, 3-methylhex-2-enoic acid (3MH2; 4/5) and 3-hydroxy-3-methylhexanoic acid (HMHA; 6) have been shown to be released from glutamine conjugates secreted in the axilla by a specific N, -acyl-glutamine aminoacylase (N-AGA) obtained from axilla isolates of Corynebacteria sp. However, the low number of different odorants reported in humans stands in contrast to the observed high inter-individual variability in body odors. Axilla secretions of individual donors were, therefore, analyzed in detail. The secretions were treated with N-AGA, analyzed by GC/MS, and compared to undigested controls. Over 28 different carboxylic acids were released by this enzyme from odorless axilla secretions (Table,1). Many of these body odorants have not been reported before from a natural source, and they include several aliphatic 3-hydroxy acids with 4-Me branches, 3,4-unsaturated, 4-Et-branched aliphatic acids, and a variety of degradation products of amino acids. The odor threshold of some of the acids was found to be in the range of 1,ng. Most of these compounds were present in all donors tested, but in highly variable relative amounts, and they are, thus, candidate molecules as key components of a ,compound odor' determining the individual types of human body odor. [source] | ||||||||||