Improved Hydroxylamine Method for the Determination of Aldehydes and Ketones. Displacement of Oxime Equilibria by Means of Pyridine

Bryant, W. M. D.; Smith, D. M.

doi:10.1021/ja01304a017

Cited by 95 publications

(38 citation statements)

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“…The results obtained by the present method agreed closely with those obtained by the method of Bryant and Smith (4). Low values obtained by both the methods in some of the samples probably resulted from the impurities carried over during distillation.…”

Section: Resultssupporting

confidence: 88%

“…The amount of earbonyl oxygen present was quantitatively determined by estimating either the amount of unreaeted hydroxylaminc (1,2) or the amount of water formed during the reaction (3), or by estimating the hydrochloric acid liberated (4,5,6,7,8). The amount of earbonyl oxygen present was quantitatively determined by estimating either the amount of unreaeted hydroxylaminc (1,2) or the amount of water formed during the reaction (3), or by estimating the hydrochloric acid liberated (4,5,6,7,8).…”

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confidence: 99%

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A method for determining the carbonyl value in thermally oxidized fats

Bhalerao

Endres

Kummerow

1961

J Americ Oil Chem Soc

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A simple method for the determination of the earbonyl value of thermally oxidized fats, using hydroxylamine hydrochloride, is described. Normal octyl alcohol containing pyridine was used as a solvent, and the reaction was allowed to proceed at room temperature for 24 hrs. The titrations were carried out with the aid of a pH meter. The method was standardized against aliphatic aldehydes and ketones. The restflts of analyses showed that the different pure compounds reacted to an extent of 98% or better at room temperature.The method has been successfully applied for the deterruination of the earbonyl value of themnally oxidized fats. n-Valeric acid and the fatty acids with higher molecular weight were not found to interfere in the determination of the carbonyl value by the present method.NUIVIBER of analytical procedures for the determination of aldehydes and ketones, based on the use of hydroxylamine hydrochloride, have been reported. The amount of earbonyl oxygen present was quantitatively determined by estimating either the amount of unreaeted hydroxylaminc (1,2) or the amount of water formed during the reaction (3), or by estimating the hydrochloric acid liberated (4,5,6, 7,8). Lappin and Clark (9) have described a procedure which employs 2,4-dinitrophenylhydrazine for determining traces of carbonyls in aqueous or alcoholic solutions. This method with some modifications was employed by Heniek et al. (10) for the determination of carbonyls in rancid fats and foods. These analytical procedures were not found to be reliable for the quantitative determination of carbonyl oxygen in thernmtly oxidized fats because of their limited solubility in all but a few suitable solvents. A method for the determination of the carbonyl content of thermally oxidized fats, using hydroxylamine hydrochloride as a reagent and n-oetyl alcohol as a suitable solvent, is presented in this paper. Experimental ReagentsHydroxylamine Hydrochloride Reagent. Thirtyfive grams of hydroxylamine hydrochloride (reagent grade) were dissolved in 160 ml. of distilled water, and the resulting solution was diluted to 1 liter with 95% earbonyl-free ethyl alcohol.Standard Sodium Hydroxide in Methanol. Twenty grams of sodium hydroxide (analytical reagent) were dissolved in a small amount of water and diluted to 1 liter with absolute methyl alcohol and standardized against standard hydrochloric acid (0.5 N).Pyridinc-octyl Alcohol Solvent. Five ml. of pyridine (analytical reagent) were diluted to 1 liter wth n-octyl alcohol.A Beeknlan ptI meter, Laboratory Model H2, equipped with standard glass electrode and standard calomel electrode, wtcs used in this work. Analytical ProcedureOne gram of the sample to be analyzed was weighed into a 250-ml. glass-stoppered Erlenmeyer flask. Fifty ml. of pyridine-oetyl alcohol solvent were pipetted into it, and, if necessary, the flask was heated on a hot plate until the sample was dissolved. Fifteen ml. of hydroxylamine hydrochloride reagent was then added with a pipette. The flask was stoppered, the contents were mixed we...

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Section: Resultssupporting

confidence: 88%

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confidence: 99%

A method for determining the carbonyl value in thermally oxidized fats

Bhalerao

Endres

Kummerow

1961

J Americ Oil Chem Soc

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“…The total content of carbonyl can be obtained by an oximation reaction with hydroxylamine hydrochloride followed by titration of the products with base sodium hydroxide, , and recently by derivatization with 4-(trifuoromethyl)phenylhydrazine followed by 19 F-NMR spectroscopy . In 1984, Nicolaides was the first to measure the carbonyl group content of pyrolysis oils based on the oximation reaction method developed by Bryant et al Faix introduced few modifications to this method, which now increased the throughput by lowering the reaction time, made it safer by replacing pyridine with triethanolamine, reduced the sample size and the dependence of the measurement from the amount of reagent left at the reaction end . The Faix method has been found to be more reliable by accounting for the carbonyl content derived from carbohydrate fraction of the biomass and by demonstrating lower standard deviation in the interlaboratory tests. , There are very few studies on the use of IR spectroscopic techniques for semiquantitative estimations of carbonyl group content in pyrolysis oils. ,, …”

Section: Introductionmentioning

confidence: 99%

Quantification of Bio-Oil Functional Groups and Evidences of the Presence of Pyrolytic Humins

et al. 2016

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Quantification of functional groups (carbonyl, carboxyl, hydroxyl, phenolics) in biomass-derived pyrolysis oils is crucial to advance our understanding of bio-oil compositional changes during production, storage, aging, and upgrading. Traditionally, most of the methods reported in the literature on this subject are based on titration. There are very few studies on the use of spectroscopic techniques for the quantification of functional groups in bio-oils. The distribution of functional groups between the volatile and the heavy fraction is also very poorly understood. The content of functional groups in the volatile fraction estimated by GC/MS was compared with their content in the total oil determined by titration and 31P NMR. The carbonyl groups are almost equally distributed between the volatile and the oligomeric fractions. The content of total phenols varies between 1.6 and 3.1 mmol/g. It is important to note that between 85 and 95% of the phenols in bio-oil are in the form of oligomers. The content of carboxylic acids varies between 1.1 and 2.1 mmol/g. Between 52 and 66% of these acids were detectable by GC/MS, and the rest is in the oligomeric form. These results confirm that the GC/MS-detectable fractionalthough it only represents around 30 wt % of the whole oilcontains more than half of the very reactive carbonyl and carboxyl functional groups of the oil. Our results suggest that as an average 56% of all the oxygen derived from the carbohydrate fraction that is collected in the oil is in the form of water. Around 20% is in the form of carbonyl groups, close to 12% is in the form of carboxylic groups, and only 17% is in the form of OH in aliphatic chains. This result clearly shows the importance of dehydration reactions (close to 70% of the oxygen in the oil is in the form carbonyl or water). The oil was studied by FT-ICR-MS. The heavy fraction is composed of oligomeric materials with up to 29 carbon atoms and 17 oxygen atoms. The Van Krevelen plots of the nonvolatile fraction show for the first time the existence of heavy unknown water-soluble oligomers produced by the gradual dehydration of cellulose primary depolymerization products. This unknown fraction is herein called “pyrolytic humin”. The oils were also analyzed by 1H NMR, FTIR, and UV fluorescence spectroscopies. 1H NMR results confirm that, with appropriate calibrations, this technique could be used to quantify the content of phenols and water. The correlations observed between FTIR spectra and titration results confirm that, with appropriate calibrations, this technique can be used for the quantification of water, carboxylic acids, and phenolics in bio-oils. A good correlation was obtained between the total content of phenols measured by Folin–Ciocalteu and the area of the UV fluorescence peaks.

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“…The next major contribution to the oximation of carbonyl groups was that of Bryant and Smith (5) in 1935. They used a dilute 2% pyridine solution in ethanol.…”

Section: Early Oximation Methodsmentioning

confidence: 99%

Determination of the Carbonyl Group: Oximation and Other Methods

Schenk

1968

Organic Functional Group Analysis

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Improved Hydroxylamine Method for the Determination of Aldehydes and Ketones. Displacement of Oxime Equilibria by Means of Pyridine

Cited by 95 publications

References 2 publications

A method for determining the carbonyl value in thermally oxidized fats

A method for determining the carbonyl value in thermally oxidized fats

Quantification of Bio-Oil Functional Groups and Evidences of the Presence of Pyrolytic Humins

Determination of the Carbonyl Group: Oximation and Other Methods

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