noun
definition
A homologous series of organic molecules whose functional group is an oxygen atom joined to a carbon atom—by a double bond—in a carbon-hydrogen based molecule.
Examples of ketones in a Sentence
The tertiary glycols are known as pinacones and are formed on the reduction of ketones with sodium amalgam.
By the action of dehydrating agents they are converted into aldehydes or ketones.
Experience has shown that such mono-derivatives as nitro compounds, sulphonic acids, carboxylic acids, aldehydes, and ketones yield as a general rule chiefly the meta-compounds, and this is independent of the nature of the second group introduced; on the other hand, benzene haloids, amino-, homologous-, and hydroxy-benzenes yield principally a mixture of the orthoand para-compounds.
This is true of the fatty acid series, and the corresponding ketones and alcohols, and also of the succinic acid series.
The same difference attends the introduction of the methyl group into many classes of compounds, for example, the paraffins, olefines, acetylenes, aromatic hydrocarbons, alcohols, aldehydes, ketones and esters, while a slightly lower value (157.1) is found in the case of the halogen compounds, nitriles, amines, acids, ethers, sulphides and nitro compounds.
It is remarkable that the difference in the heats of formation of ketones and the paraffin containing one carbon atom less is 67.94 calories, which is the heat of formation of carbon monoxide at constant volume.
Those derived from aldehydes are known as aldoximes, those from ketones as ketoximes.
They are prepared by condensing thio-amides with a-haloid ketones or aldehydes, the thio-amide reacting as the tautomeric thio-imino acid.
Amino derivatives similarly result from thio-ureas and a-haloid ketones; the oxy derivatives from a-sulphocyanoketones by the action of caustic alkali; and the carboxylic acids from chloro-aceto-acetic ester, &c. and thioamides.
In organic chemistry, his study of the ketones and aldehydes, begun in 1857, provided him with the subject of his other doctoral thesis.
Wallach, Ber., 1881, 14, P. 421); by the action of reducing agents on nitroparaffins; by the action of zinc and hydrochloric acid on aldehyde ammonias (German Patent 73,812); by the reduction of the phenylhydrazones and oximes of aldehydes and ketones with sodium amalgam in the presence of alcohol and sodium acetate (J.
Ketones, secondary alcohols and tertiary alcohols yield a mixture of acids on oxidation.
The calcium salts distilled with calcium formate yield aldehydes r distilled with soda-lime, ketones result.
It condenses with aldehydes and ketones to produce semioxamazones.
It combines with aldehydes and ketones to form the nitriles of oxy-acids, for example, CH 3 CHO+HCN=CH 3 CH(OH)(CN).
For the formation of primary and secondary alcohols see Aldehydes and Ketones.
The ketones are of neutral reaction, the lower members of the series being colourless, volatile, pleasant-smelling liquids.
The -y-diketones are characterized by the readiness with which they yield furfurane, pyrrol and thiophene derivatives, the furfurane derivatives being formed by heating the ketones with a dehydrating agent, the thiophenes, by heating with phosphorus pentasulphide, and the pyrrols by the action of alcoholic ammonia or amines.
And so, as a rule, from isomeric alcohols, those containing a group - CH 2.0H, yield by oxidation aldehydes and are distinguished by the name primary; whereas those containing CH OH, called secondary, produce ketones.
These compounds generally behave as ketones; but at the same time they may act as alcohols, i.e.
Villiger (Be y ., 1901, 34, pp. 2679, 3612) showed that many organic compounds (ethers, alcohols, aldehydes, ketones, &c.) behave towards acids, particularly the more complex acids, very much like bases and yield crystallized salts in which quadrivalent oxygen must be assumed as the basic element.
Acetoacetic ester is a most important synthetic reagent, having been used in the production of pyridines, quinolines, pyrazolones, furfurane, pyrrols, uric acid, and many complex acids and ketones.
It condenses under the influence of sulphuric acid to form dodecahydrotriphenylene, C H and a mixture of ketones (C. Mannul, Ber., 1907, 40, p. 153).
For example, on reduction with zinc and alcoholic potash, the a/' compounds give saturated ketones and also bi-molecular compounds, the Jay being unaffected; the Jay series react with hydroxylamine in a normal manner, the a/3 yield oxamino-oximes.
With aldehydes and ketones it forms oximes.
Secondary alcohols yield ketones, which are subsequently oxidized to a mixture of two acids.
Tertiary alcohols yield neither aldehydes nor ketones, but a mixture of two or more acids.
Secondary alcohols result from the reduction of ketones; and from the reaction of zinc alkyls on aldehydes or formic acid esters.
The aldehydes and ketones provided material for his earlier work.
He observed that aldehydes and ketones may suffer reduction in neutral, alkaline, and sometimes acid solution to secondary and tertiary glycols, substances which he named pinacones; and also that certain pinacones when distilled with dilute sulphuric acid gave compounds, which he named pinacolines.
The thiophen ketones may be prepared by the interaction of thiophen and its homologues with acid chlorides in the presence of anhydrous aluminium chloride.
They combine with aldehydes and ketones, with elimination of water and formation of mercaptals and mercaptols.
The products of oxidation are not yet fully known; most likely they consist of lower fatty acids, such as formic and acetic acids, and perhaps also of aldehydes and ketones.
The aldol condensation (using aldehydes, ketones, two different carbonyl partners, and the intramolecular variant ).
For example, methanal, ethanal and propanone - the common small aldehydes and ketones - are miscible with water in all proportions.
Ketoacidosis If you are producing ketones and are not treated with insulin, you will develop a serious condition called ketoacidosis.
But when you have diabetes rising blood glucose and rising blood ketones can go together.
You should not exercise if your blood sugar is more than 14 mmol/l and you have ketones present in your urine.
Therapeutic opportunities The ability of the brain to use ketones was only once exploited for therapeutic purposes.
Many people with diabetes can benefit from measuring blood ketones as part of their overall diabetes management program.
Click here to find out more about testing blood ketones.
Ketones do not polymerize in the same way as aldehydes, but under the influence of acids and bases yield condensation products; thus acetone gives mesityl oxide, phorone and mesitylene (see below).
Many cyclic ketones are known, and in most respects they resemble the ordinary aliphatic ketones (see Polymethylenes; Terpenes).
Ketones are acid compounds that form in the blood when the body breaks down fats and proteins for energy.
When blood sugars are high (i.e., over 249 mg/dl, or 13.8 mmol/L) for prolonged periods of time, ketones build up in the bloodstream to dangerous levels.
As an alternate source of energy, fat cells are broken down, producing ketones, toxic compounds that make the blood acidic.
Type I diabetes usually occurs in childhood and is associated with low or absent blood insulin and production of ketones even in the absence of stressed metabolic conditions.
The physician may also perform enzyme studies on or look for the presence of "reducing substances" in the child's urine, look for ketones in the urine, and measure enzyme activity in the red blood cells.
If elevated glucose levels are present, the doctor will want to determine if ketoacidosis is also present by measuring levels of ketones in the blood serum and urine.
Burning fat produces chemicals called ketones.