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1.
Hradilek P. Kronrád L. Bečicová M. Pereszlényiová E. Kasalický J. 《Journal of Radioanalytical and Nuclear Chemistry》1990,144(2):151-160
A simple method for labelling fatty acids with iodine radionuclides is reported. 16-[123I]iodohexadecanoic, 17-[123I]iodoheptadecanoic and 18-[123I]iodooctadecanoic acids were prepared by exchange reaction in ethanolic solution. The best results in biodistribution studies were obtained with 18-[123I]iodooctanoic acid. 相似文献
2.
《Analytical letters》2012,45(5-6):565-573
Abstract The distribution of Pb(II) between an aqueous phase and a toluene phase containing dehydrated fatty acids found in distilled castor oil (AGDOMD) has been studied. Using the slope technique the conditional equilibrium constant of extraction was determined (kext = 1.02 × 10?7) and the main species present in the organic phase was identified as (PbNO3R. 2HR)(o), where HR represents the fatty acid used. 相似文献
3.
Kinetics of oxidation of thiocyanate ion (NCS?) by iodine monochloride and iodine has been studied in aqueous perchloric acid medium. The rates of oxidations followed the rate laws: Variations in ionic strength and dielectric constant of the medium had little effects on the rates of reactions with both the oxidants. Mechanisms consistent with the observed rate laws have been suggested. Rate limiting steps have been identified and the constants of some of these steps have been evaluated by varying [NCS?] at each temperature. Activation parameters were computed from the Arrhenius plots. The rate constants predicted from the rate law as [NCS?], and [H+], varied in iodine monochloride oxidation, are in good agreement with the experimental values providing support to the proposed mechanism. 相似文献
4.
Syntheses of the two stereoisomeric 10-hydroxydec-2-enoic acids are described. The trans-isomer is identical with the main fatty acid isolated from royal jelly of honeybees.
Some compounds closely related to this trans-acid have also been prepared.
A convenient process for the preparation of 10-acetoxy-decanoic acid from castor oil has been developed. 相似文献
5.
1. The use of permanganate, ceric sulphate, and dichromate for the estimation of sulphite has been reinvestigated, although these reagents have heen discarded as useless by earlier investigators. By using catalysts under controlled acid concentration, we have been able to develop conditions for the quantitative oxidation of sulphite to sulphate at room temperature by any one of these oxidizing agents, avoiding the formation of dithionate. Copper sulphate and iodine monochlonde have been found useful as catalysts with potassium permanganate and dichromate; but only iodine monochloride with ceric sulphate. 2. Sodium sulphite is also oxidized quantitatively to sulphate at room temperature, when added to excess of sodium vanadate solution containing 5 to 6N hydrochloric acid and iodine monochloride as catalyst. 相似文献
6.
Assessment of Fatty Acid Profile and Seed Mineral Nutrients of Two Soybean (Glycine max L.) Cultivars Under Elevated Ultraviolet‐B: Role of ROS,Pigments and Antioxidants 下载免费PDF全文
Current scenarios under global climate change envisage a considerable increase in ultraviolet B (UV‐B) radiation in near future which may affect the productivity and yield quality of major agricultural crops. Present investigation was conducted to examine various defense strategies adopted against elevated UV‐B (ambient + 7.2 kJ mˉ2 dayˉ1) and their impact on seed nutrients, content and quality of oil including fatty acid profile of two soybean cultivars (JS‐335 and PS‐1042). Elevated UV‐B (eUV‐B) exposure leads toward higher unsaturation of fatty acids and changes in other oil quality parameters (acid, iodine and saponification value) indicated that eUV‐B favored the synthesis of long‐chain fatty acids with fewer carboxylic acid groups, making the oil rancid, with undesirable flavor and low nutritional value. The effect was more severe in JS‐335 as compared to PS‐1042. Negative effects were also seen on nutrients of soybean seeds. Adverse effects resulted due to insufficient quenching of ROS (superoxide radical and hydrogen peroxide) by the defense system and thus unable to overcome the imposed oxidative stress. Credit of better performance by PS‐1042 against eUV‐B may be given to the adoption of efficient defense strategies like higher wax deposition, increase in lignin and flavonoids (quercetin and kaempferol) contents. 相似文献
7.
In hydrochloric acid medium sodium meta-vanadate was used as a volumetric reagent for the determination of copper, zinc, cobalt, mercury, and lead. Cu+2, Zn+2 and Co+2were precipitated as complex mercurythiocyanates, Hg+2 as mercuric zinc thiocyanate and Pb+2 as Iodide. The thiocyanates were dissolved in concentrated hydrochloric acid and titrated against standard sodium meta-vanadate solution in the presence of iodine monochloride as a pie.oxidizer and catalyst. In titration of the iodide against the meta-vanadate. it was not necessary to add iodine monochloride to the titrant because it is formed during the titration. Chloroform was used as an indicator. It was pink owing to the liberation of iodine during the titration and became pale yellow at the end-point because of the formation of iodine monochlonde. 相似文献
8.
Previous studies have shown that ricinoleic acid from castor bean oil of Ricinus communis is synthesized by the direct hydroxyl substitution of oleate, while it has been proposed that ricinoleate is formed by hydration of linoleate in the ergot fungus Claviceps purpurea. The mechanism of the enzymes specific to ricinoleate synthesis has not yet been established, but hydroxylation and desaturation of fatty acids in plants apparently involve closely related mechanisms. As mechanistic differences in the enzymes involved in the biosynthesis of natural products can lead to different isotopic distributions in the product, we could expect ricinoleate isolated from castor or ergot oil to show distinct (2)H distribution patterns. To obtain information concerning the substrate and isotope effects that occur during the biosynthesis of ricinoleate, the site-specific natural deuterium distributions in methyl ricinoleate isolated from castor oil and in methyl ricinoleate and methyl linoleate isolated from ergot oils have been measured by quantitative (2)H NMR. First, the deuterium profiles for methyl ricinoleate from the plant and fungus are equivalent. Second, the deuterium profile for methyl linoleate from ergot is incompatible with this chemical species being the precursor of methyl ricinoleate. Hence, it is apparent that 12-hydroxylation in C. purpurea is consistent with the biosynthetic mechanisms proposed for R. communis and is compatible with the general fundamental mechanistic similarities between hydroxylation and desaturation previously proposed for plant fatty acid biosynthesis. 相似文献
9.
Diethylenetetra-ammonium sulphatocerate has been used as an oxidising agent in hydrochloric acid medium for the volumetric determination of semicarbazide hydrochloride, benzalazine, benzalsemicarbazone, aminoguanidme hydrochloride, chloralhydrazinc, P-methoxybcnzalsemicarbazonc, o-chlorobenzalsemicarbazone and acetonesemicarbazone, using iodine monochloride as a catalyst and preoxidiser Chloroform was used as an indicator. It was coloured violet owing to the liberation of iodine during the titration and became very pale yellow at the end-point owing to the formation of iodine monochloride Each hydrazino group in these compounds was oxidised quantitatively with a four-electron change to nitrogen with diethylenetctra-ammonium sulphatocerate as an Oxidant in hydrochloric acid solution. 相似文献
10.
Chloramine-T has been used as an oxidizing agent in hydrochloric acid medium' for the volumetric estimations of potassium iodide, hydrazine sulphate, arscnious oxide, stannous chloride, mercurous chloride, tartar-emetic, potassium thiocyanate and ferrous ammonium sulphate, using iodine monochloride as a catalyst and pre-oxidizer. Chloroform is used as an indicator. It is coloured pink owing to the liberation of iodine during the titration and becomes very pale yellow at the end-point because of the formation of iodine monochloride. 相似文献
11.
Chloramine-T has been used as an oxidizing agent in hydrochloric acid medium for the indirect volumetric determination of hydrogen peroxide, lead dioxide, selenium dioxide, sodium formate, potassium meta-periodate, potassium permanganate and potassium dichromate using iodine monochloride as a catalyst, prcoxidizer and an indicator. Chloroform is coloured pink owing to the liberation of iodine during the titration and becomes very pale yellow at the end-point because of the formation of iodine monochloride. 相似文献
12.
Summary Sodium hypochlorite solution has been used as an oxidising agent for the volumetric determination of semicarbazide hydrochloride, phenylhydrazine hydrochloride, benzalazine, benzalsemicarbazone, o-chlorobenzalsemicarbazone, acetonesemicarbazone, aminoguanidine hydrochloride, thiosemicarbazide, o-hydroxy benzalsemicarbazone, 3,4-methylenedioxy benzalsemicarbazone and p-methoxy benzalsemicarbazone, using iodine monochloride as catalyst and preoxidizer. During these titrations normality of the solution with respect to hydrochloric acid has been kept between 2.0 N and 3.5 N. Chloroform is used as an indicator. It is coloured pink due to the liberation of iodine during the titration and becomes very pale yellow at the end-point owing to the formation of iodine monochloride. Each hydrazino group in these compounds is oxidised quantitatively with a four-electron change to nitrogen with sodium hypochlorite as an oxidant in hydrochloric acid solution. 相似文献
13.
《Comptes Rendus Chimie》2015,18(4):410-421
Herein, we present our results related to the synthesis of colloidal solutions of gold nanoparticles (AuNPs) dispersed in castor oil. These colloids were prepared via a wet chemistry process by mixing specific amounts of castor oil, ethanol, and aqueous solutions of tetrachloroauric(III) acid and sodium hydroxide. The size and shape of the AuNPs obtained could be modulated by the amount of gold source added and the Au/OH– molar ratio used. In this study, we observed that the free fatty acid content in the reaction medium was an important parameter to be considered in the syntheses of the colloidal solutions and the respective form and shape of the AuNPs produced. Thus, we evaluated the effect of oil acidity by adding different amounts of myristic acid (MA) in the reaction medium. The colloids were characterized by UV–vis spectroscopy, and the size and shape of the AuNPs produced were characterized by transmission electron microscopy (TEM). 相似文献
14.
Rosiane M. C. Farias Marta M. Conceição Roberlúcia A. Candeia Marta C. D. Silva Valter J. FernandesJr. Antonio G. Souza 《Journal of Thermal Analysis and Calorimetry》2011,106(3):651-655
The diversity of raw materials and technological routes employed in the biodiesel production has resulted in products with
different chemical properties. This non-uniformity in the biodiesel composition may influence to the fuel quality. The aim
of this study was to evaluate biodiesel blends of passion fruit and castor oil in different proportions and their thermal
stability. Biodiesel blends of passion fruit and castor oil presented parameters in the standards of the Petroleum, Natural
Gas and Biofuels National Agency. The TG curves indicated that castor oil biodiesel was more stable. Passion fruit biodiesel
has a high content of oleic and linoleic acids, which are more susceptible to oxidation. Biodiesel blend of passion fruit
and castor oil 1:1 increased the thermal stability in relation to passion fruit biodiesel. Biodiesel blend of passion fruit
and castor oil 1:2 presented higher thermal stability, because castor oil has a high content of ricinoleic acid. 相似文献
15.
Sodium meta-vanadate has been used as an oxidising agent in hydrochloric acid medium for the volumetric estimations of potassium iodide, sodium arsenite, mercurous chloride, potassium thiocyanate, sodium sulphite, sodium bisulphite, sodium thiosulphate, ferrous sulphate and hydrazine sulphate, using iodine monochloride as a catalyst and preoxidiser. Chloroform is used as an indicator. It is coloured pink due to the liberation, of iodine during the titration and becomes light pale yellow at the end-point due to the formation of iodine monochloride. 相似文献
16.
Chloramine-B has been used as an oxidizing agent in hydrochloric acid medium for the volumetric estimations of potassium iodide, arsenious oxide, tartar-emetic, mercurous chloride, stannous chloride, potassium thiocyanate, ferrous ammonium sulphate, hydrazine sulphate and hydroquinone, using iodine monochloride as a catalyst and pre-oxidizer. Chloroform is used as an indicator. It is coloured pink owing to the liberation of iodine during the titration and becomes light pale yellow at the end-point because of the formation of iodine monochloride. 相似文献
17.
I. El Mannoubi S. Barrek T. Skanji H. Casabianca H. Zarrouk 《Chemistry of Natural Compounds》2009,45(5):616-620
The lipid fraction of Opuntia ficus indica seeds was extracted and analyzed for its chemical and physical properties such as acid value, free fatty acid percentage
(% FFA), iodine index, peroxide value, and saponification value as well as refractive index and density. The yield of seed
oil was calculated as 11.75%. The acid and free fatty acid values indicated that the oil has a fairly low acidity. The triacylglycerols,
fatty acids, sterols, and tocopherols were identified and their concentrations determined. The main TAGs were LLL (25.60%),
OLL (21.53%), PLL (15.53%), and POL + SLL (12.73%). Linoleic acid (60.69%) was the dominant fatty acid, followed by oleic
(21.42%) and palmitic (12.76%) acids, respectively. A high level of sterols making up 16.06 g/kg seed oil was present. The
sterol marker, β-sitosterol, accounted for 71.60% of the total sterol content in the seed oil. Among the tocopherols present
in the oil, γ-tocopherol (421.08 mg/kg) was the main constituent. 相似文献
18.
Salha Hamri Jose Rodríguez Joan Basset Gérald Guillaumet M. Dolors Pujol 《Tetrahedron》2012,68(31):6269-6275
We report a direct iodination of indole and derivative compounds with iodine monochloride (ICl) in the presence of Celite®. This procedure has now been extended to the iodination of substituted indoles, azaindoles and pyrroles. The scope of this procedure is exemplified by the iodination of melatonin in 98% yield. 相似文献
19.
Sodium metavanadate has been used as an oxidising agent in hydrochloric acid medium for the volumetric determination of semicarbazide hydrochloride, benzalazine, benzalsemicarbazone, aminoguanidine hydrochloride, o-hydroxybenzalsemicarbazone, p-methoxybenzalsemicarbazone, chloralhydrazine, o-chlorobenzalsemicarbazone and ethyl methyl ketone semicarbazone, using 10-dine monochloride as a catalyst and preoxidiser Chloroform was used as an indicator. It was coloured violet due to the liberation of iodine during the titration and became light pale yellow at the end-point owing to the formation of iodine monochloride Eachhydrazino group in these compounds was oxidised quantitatively with a four-electron change to nitrogen with sodium metavanadate as an oxidant in hydrochloric acid solution. 相似文献
20.
Chloramine-B has been used as an oxidizing agent in hydrochloric acid medium for the indirect volumetric estimations of hydrogen peroxide, lead dioxide, manganese dioxide, selenium dioxide, sodium formate, sodium sulphide, sodium metavanadate, potassium iodate and copper sulphate using iodine monochloride as a catalyst and pre-oxidiser. Chloroform is used as an indicator. It is coloured pink owing to the liberation of iodine during the titration and becomes light pale yellow at the end-point because of the formation of iodine monochloride. 相似文献