Butyl 889926 221608092 2008-06-25T07:39:52Z Zorrobot 7218328 robot Adding: [[sv:Butyl]] In [[organic chemistry]], '''butyl''' is a four-[[carbon]] [[alkyl]] [[radical (chemistry)|substituent]] with [[chemical formula]] '''-C<sub>4</sub>H<sub>9</sub>''' . It is derived from either of the two isomers of the [[alkane]] called [[butane]]. Each of the two [[isomer]]s of butane give rise to two [[isomers]] of the butyl substituent. Thus, ''n''-butane can connect at either the terminal or an internal carbon atoms, giving rise to "''n''-butyl" and "''sec''-butyl" substituents. * '''''n''-Butyl''' group: CH<sub>3</sub>–CH<sub>2</sub>–CH<sub>2</sub>–CH<sub>2</sub>– (fully systematic name: butyl) * '''''sec''-Butyl''' group: CH<sub>3</sub>–CH<sub>2</sub>–CH(CH<sub>3</sub>)– (fully systematic name: 1-methylpropyl) The second, branched isomer of butane, [[Isobutyl|isobutane]] can also connect either terminal methyl or internal carbon atoms, giving rise to "isobutyl" and "tertiary butyl" substituents, respectively. * '''Isobutyl''' group: (CH<sub>3</sub>)<sub>2</sub>CH–CH<sub>2</sub>– (fully systematic name: 2-methylpropyl) * '''''tert''-Butyl''' group: (CH<sub>3</sub>)<sub>3</sub>C– (fully systematic name: 1,1-dimethylethyl) ==Nomenclature== According to [[IUPAC nomenclature]], "isobutyl", "''sec''-butyl", and "''tert''-butyl" are all retained trivial names. {| class="wikitable" |[[skeletal formula]] |[[common name]] |IUPAC name |[[systematic name]] |alternate notation |- |[[Image:Butyl-group-2D-skeletal.png|100px]] |''n''-butyl |butyl |butyl |butan-1-yl |- |[[Image:Isobutyl-group-2D-skeletal.png|80px]] |isobutyl |isobutyl |2-methylpropyl |2-methylpropan-1-yl |- |[[Image:Sec-butyl-group-2D-skeletal.png|80px]] |''sec''-butyl |''sec''-butyl |1-methylpropyl |butan-2-yl |- |[[Image:Tert-butyl-group-2D-skeletal.png|60px]] |''tert''-butyl |''tert''-butyl |1,1-dimethylethyl |2-methylpropan-2-yl |} Butyl is the largest substituent for which trivial names are commonly used for all isomers. The prefixes iso, <i>sec</i> and <i>tert</i> refer to the number of carbons connected to the [[primary carbon]] (also known as R<sup>I</sup> ("R prime"), the carbon that is connected to R). Iso means one, <i>sec</i>- means two and <i>tert-</i> means three. ==Some examples== The following are the four isomers of "butyl acetate": {| |[[Image:Butyl acetate.png|200px|butyl acetate]] |[[Image:Isobutyl acetate.png|150px|isobutyl acetate]] |[[Image:S-butyl acetate.png|150px|sec-butyl acetate]] |[[Image:T-butyl acetate.png|120px|tert-butyl acetate]] |- |<center>[[Butyl acetate|''n''-butyl acetate]]</center> |<center>[[isobutyl acetate]]</center> |<center>[[Sec-Butyl acetate|''sec''-butyl acetate]]</center> |<center>[[Tert-Butyl acetate|''tert''-butyl acetate]]</center> |} == Etymology== As the number of carbons in an alkyl chain increases, butyl is the last to be named historically instead of through [[Greek language|Greek]] numbers. The name is derived from [[butyric acid]], a four carbon [[carboxylic acid]] found in [[decomposition|rancid]] [[butter]]. The name of butyric acid, in turn, comes from [[Latin]] ''butyrum'', "butter". ==Tert-butyl effect== The tert-butyl [[substituent]] is very bulky and used in chemistry for [[kinetic reaction control|kinetic stabilisation]] together with other bulky groups such as the related [[trimethylsilyl]] group. The effect that the t-butyl group exerts on the progress of a chemical reaction is called the '''tert-butyl effect'''. This effect is illustrated in the [[Diels-Alder reaction]] below where the tert-butyl substituent causes a [[reaction rate]] acceleration by a factor of 240 compared to hydrogen as the substituent.<ref>''Factors affecting ease of ring formation. The effect of anchoring substitution on the rate of an intramolecular diels-alder reaction with furan-diene'' Serge Cauwberghs and Pierre J. De Clercq B. Tinant and J. P. Declercq [[Tetrahedron Letters]] Volume 29, Issue 20 , '''1988''', Pages 2493-2496 {{doi|10.1016/S0040-4039(00)87916-2}}</ref> [[Image:Tertbutyleffect.png|center|400px|Tert-butyl effect]] == See also == * [[Methyl]] * [[Ethyl]] * [[Propyl]] * [[Pentyl]] / [[amyl]] ==References== <div class="references-small"><references/></div> [[Category:Functional groups]] [[de:Butylgruppe]] [[pl:Grupa butylowa]] [[ru:Бутил]] [[sv:Butyl]]