共查询到20条相似文献,搜索用时 171 毫秒
1.
Higherfattyalcoholgallicestersarereportedasfinefoodantioxidantslandcolordevelopingagents'forheatsensitiverecordingpaperorcarbonlesspaper.Theyareusuallysynthesizedbyoneoftwomainmethods:esterificationofgallicacid3andtransesterificationofmethylorethylesters4.Themaindisadvantagesofsomeofthosemethodsaretheuseofuncommonreagentsanddifficultwork-up.Wewishtoreportasimplesyntheticprocedureutilizingmicrowaveirradiations'6undersolventffreeconditions,differentacids,includingMontmorilloniteK10andp-toluenes… 相似文献
2.
3.
JPC – Journal of Planar Chromatography – Modern TLC - Homologous series of higher fatty acids, higher alcohols, and methyl esters of higher fatty acids have been separated by RPTLC. The... 相似文献
4.
5.
Kazuo Fukushima 《Journal of Analytical and Applied Pyrolysis》1983,5(3):245-256
Significant amounts of fatty acids and alcohols, in addition to straight-chain hydrocarbons, were observed in the vacuum pyrolysate of a young kerogen isolated from a fresh-water sediment. The amounts and the distribution patterns of fatty acids and alcohols were compared with those indigenous to the original kerogen, as determined by solvent extraction followed by saponification extraction. Straight-chain fatty acids in the pyrolysate were 12.7 mg/g kerogen, while those extracted from the original kerogen were 10.5 mg/g. The amounts of fatty alcohols in the pyrolysate and in the extracts were 1.31 and 1.10 mg/g. respectively. The excess amounts in the pyrolysate were explained by the release of a strictly bound form of fatty acids and alcohols, which were left in the kerogen matrix even after the saponification extraction. The results indicated that most fatty acids and alcohols were not decomposed as a result of the vacuum pyrolysis and that neither fatty acids nor fatty alcohols should be viewed as the prime precursors of the straigth-chain hydrocarbons (4.6 mg/g) simultaneously generated during vacuum pyrolysis. 相似文献
6.
D. A. Stepanov A. Ermakova V. I. Anikeev 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(1):21-25
The objects of study were mixtures containing triglycerides and lower alcohols and also the products of the transesterification
of triglycerides, glycerol and fatty acid esters. The Redlich-Kwong-Soave equation of state was used as a thermodynamic model
for the phase state of the selected mixtures over wide temperature, pressure, and composition ranges. Group methods were applied
to determine the critical parameters of pure substances and their acentric factors. The parameters obtained were used to calculate
the phase diagrams and critical parameters of mixtures containing triglycerides and lower alcohols and the products of the
transesterification of triglycerides, glycerol and fatty acid esters, at various alcohol/oil ratios. The conditions of triglyceride
transesterification in various lower alcohols providing the supercritical state of reaction mixtures were selected. 相似文献
7.
Salechi P. Khodaei M. M. Ghareghani S. B. Motlagh A. R. 《Russian Journal of Organic Chemistry》2003,39(6):794-796
Aliphatic alcohols and water in the presence of catalytic amounts of Fe3+ ion introduced as acids esterification with various type alcohols was carried out using the system Fe(ClO4)3-silica gel in dichloromethane under conditions excluding solvolysis. Acetylation and formylation of alcohols was performed by efficient transesterification with ethyl acetate and ethyl formate. 相似文献
8.
Aromatic and aliphatic aldoximes or their O-methyl ethers can be efficiently converted into the corresponding carboxylic acid esters by treatment with an alcoholic solution of 30% hydrogen peroxide in the presence of catalytic amounts of 2-nitrobenzeneseleninic acid. Primary alcohols give excellent to good yields, secondary ones - good to moderate, but with tertiary alcohols no esterification is obserwed. 相似文献
9.
A couple of years ago, Fujita and co-workers1 reported the reduction of 2-thiazoline-2-thiol esters to alcohols with sodium borohydride in aqueous tetrahydrofuran. In connection with an ongoing synthetic project which requires the selective reduction of a stable acid derivative to the alcohol level in the presence of nitrile and ester groups, we examined the reaction of a variety of thiol esters with sodium borohydride. Our results show that the highly reactive (and thus unstable) 2-thiazoline-2-thiol ester derivatives are unnecessary and in fact various types of thiol esters are readily convertible to alcohols under mild conditions which do not effect the reduction of common acid derivatives such as nitrile, ester, and amide. 相似文献
10.
Trace analysis of surfactants derived from fatty alcohols I. Optimization of derivatization reaction
Summary Pre-column derivatization of the primary hydroxyl group in fatty alcohols and fatty alcohol ethoxylates using carbazole-9-carbonyl
chloride (CC−Cl) and FMOC-Cl is described and compared with derivatization with 1-naphthoyl chloride (N−Cl). As the excess
of derivatization reagent leads to a broad and strongly tailing reagent peak, it hinders trace determination of fatty alcohols
and fatty alcohol ethoxylates. Therefore, an off-line as well as an on-line solid-phase extraction (SPE) method for removal
of excess reagent are described. The on-line method which is based on column switching, shows better reproducibility higher
pre-concentration, lower risk of contamination and can be easily automated, while the off-line method is better suited for
the analysis of derivatized, fatty alcohol ethoxylates. An example of the trace analysis of fatty alcohols with a concentration
of 2 ppb is given. 相似文献
11.
Catalytic conversion of unsaturated alcohols to their corresponding aldehydes and ketones with nonacarbonyl diiron in benzene at 40–50 C are performed efficiently in high yields. The efficient preparation of some enol ethers and also preperation of a few esters from their corresponding unsaturated ethers and esters are also performed by this method. 相似文献
12.
SHANG Yan-mei LI Jing SONG Zhi-guang LI Ye-zhi HUANG Hua-min 《高等学校化学研究》2007,23(4):430-432
A series of esters of R-tetrahydrothiazo-2-thione-4-carboxylic acid[R-TTCA] was synthesized by direct esterification of R-TTCA with alcohols(CH3OH,C2H5OH,n-C3H7OH,i-C3H7OH,n-C4H9OH,sec-C4H9OH)in the presence of TiCl4 as the catalyst at room temperature without using any other solvent or dehydrant in high yields,91.6%-99.1% for primary alcohols and 55%- 80% for secondary alcohols.The catalyst has a strong chemoselective activity for the esterification of primary alcohols with R-TTCA in the presence of secondary alcohols.Owing to high yield,high chemoselectivity,and mild conditions used,this is an efficient method for the esterification of primary alcohols with R-TTCA. 相似文献
13.
We describe a simple and sensitive method to identify and quantitate long-chain fatty alcohols. Long-chain fatty alcohols were converted to their pentafluorobenzoyl derivative and analyzed by gas chromatography (GC)-mass spectrometry in the negative ion chemical ionization (NICI) mode with selected ion monitoring. GC resolution was obtained for myristyl, palmityl, heptadecyl, stearyl, oleyl, linoleyl and arachidonyl alcohols. As little as 0.4 fmol of fatty alcohol can be detected, which represents a six order-of-magnitude increase in sensitivity over previously described methods. This assay can be used to measure femtomolar amounts of long-chain acyl coenzyme A thioesters after reduction to the corresponding fatty alcohols with sodium borohydride. Other potential applications of this assay include identification and quantitation of long-chain fatty alcohol production by microorganisms. 相似文献
14.
A mild transformation of various amides and imides into the corresponding esters and diesters in good yields by using chlorotrimethylsilane and alcohols at rt are described. Either primary, secondary, or tertiary amide or imide can be used in this transformation. Primary and secondary alcohols gave better yields than tertiary alcohols. 相似文献
15.
Analysis of alcohols, as dimethylglycine esters, by electrospray ionization tandem mass spectrometry
Johnson DW 《Journal of mass spectrometry : JMS》2001,36(3):277-283
Dimethylglycine (DMG) esters are new derivatives for the rapid, sensitive and selective analysis of primary and secondary alcohols, in complex mixtures, by electrospray ionization tandem mass spectrometry (ESI-MS/MS). Their development was inspired by the use of the complementary dimethylaminoethyl esters for the trace, rapid analysis of fatty acids. DMG esters are simply prepared by heating a dichloromethane solution of the imidazolide of dimethylglycine, containing triethylamine, and an alcohol. DMG esters of long-chain fatty alcohols, isoprenoidal alcohols and hydroxy-acids are analysed by electrospray ionization tandem mass spectrometry with a precursor ion of m/z 104 scan. Diols, glyceryl esters, glyceryl ethers and some sterols are analysed by a neutral loss of 103 Da scan. Trimethylglycine (TMG) ester iodides, prepared by alkylation of DMG esters with methyl iodide, are more sensitive derivatives for molecules containing secondary alcohol groups, such as cholesterol and gibberellic acid. They are analysed by a precursor ion of m/z 118 scan. DMG or TMG derivatives were shown to be at least comparable and sometimes an order of magnitude more sensitive than N-methylpyridyl ether derivatives for ESI-MS/MS analysis of the different classes of alcohols. Applications of these derivatives for the diagnosis of inherited disorders and the analysis of natural products are presented. 相似文献
16.
K.Dharmalingam K.Ramachandran P.Sivagurunathan G.M.Kalamse 《物理化学学报》2007,23(1):50-54
Acrylic esters are industrially important chemicals, which are used as adhesives, paints, binders, and emulsifiers[1]. Alcohols play an important role in many chemical reactions because of their ability to undergo self-association with manifold internal s… 相似文献
17.
Dikusar E. A. Kozlov N. G. Moiseichuk K. L. 《Russian Journal of Organic Chemistry》2002,38(2):182-187
By treating 1-octyne and phenylacetylene with butyllithium the corresponding lithium acetylides were obtained that with camphor and isocamphanone provided along streospecific process 2-exo-(1-octynyl or 2-phenyl-1-ethynyl)-2-endo-lithiumoxy-5,5,6-trimethylbicyclo[2.2.1]heptane and 2-endo-(1-octynyl or 2-phenyl-1-ethynyl)-2-exo-lithiumoxy-1,7,7-trimethylbicyclo[2.2.1]heptane. The hydrolysis of these lithium alcoholates occurred selectively and resulted in individual tertiary terpene alcohols containing exo-acetylene substituent in the case of camphor, endo-acetylene fragment in the case of isocamphanone. The alcohols reacted with methyl, ethyl, or butyl iodides in the presence of hexamethylphosphoramide to afford ethers, and with benzoyl chloride to furnish disubstituted esters of benzoic acid. 相似文献
18.
(Chloromethylene)dimethylammonium chloride (Vilsmeier reagent) works as an efficient condensation reagent in the formation of carboxylic esters from carboxylic acids and alcohols under mild conditions in a one-pot procedure. Secondary alcohols are converted successively into the corresponding esters in moderate to high yields with inversion of configurations. 相似文献
19.
Summary Acid catalyzed hydrolysis of fatty alcohol sulfates under reflux condition or by microwave heating is compared. Microwave
hydrolysis turned out to be faster and more convenient to use.
The combination of reflux hydrolysis of fatty alcohol sulfates or alkyl polyglycosides and the simultaneous steam distillation
of the generated fatty alcohols gives a very powerful sample preparation and enrichment method for fatty alcohol sulfates
and alkyl polyglycosides. The preconcentrated fatty alcohols are derivatized and detected via fluorescence detection. The
applicability of the method is demonstrated by the analysis of fatty alcohol sulfates in cosmetics and in river water as matrices
spiked with approximately 4 ppb fatty alcohol sulfates. 相似文献
20.
Chenchen Li Pei Zhao Ruoling Li Bing Zhang Prof. Dr. Wanxiang Zhao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(27):11005-11009
A general efficient protocol was developed for the synthesis of carboxylic acids, esters, and amides through oxidation of alkynyl boronates, generated directly from terminal alkynes. This protocol represents the first example of C(sp)−B bond oxidation. This approach displays a broad substrate scope, including aryl and alkyl alkynes, and exhibits excellent functional group tolerance. Water, primary and secondary alcohols, and amines are suitable nucleophiles for this transformation. Notably, amino acids and peptides can be used as nucleophiles, providing an efficient method for the synthesis and modification of peptides. The practicability of this methodology was further highlighted by the preparation of pharmaceutical molecules. 相似文献