In chemical called liqor to those organic chemical compounds containing a hydroxyl group (-OH) in replacing a hydrogen atom covalently bonded to a carbon atom. Besides this carbon must be saturated, ie must have only single bonds to two separate atoms, one that differentiates liqor-phenols. If containing several hydroxyl groups are called polyols (alcohol assessment).
The acidity of hydroxyl group is similar to that of water, although it depends mainly steric hindrance and the inductive effect. If a hydroxyl is bonded to a tertiary carbon, it is less acidic than if he were bound to a secondary carbon, and in turn it would be less acidic than if I was bound to a primary carbon, because steric hindrance prevents the molecule is effectively solvate. The inductive effect increases the acidity of liqor if the molecule has a large number of electronegative atoms attached to adjacent carbons (electronegative atoms help stabilize the negative charge of oxygen by electrostatic attraction).
On the other hand, oxygen has two unshared pairs of electrons so that the hydroxyl could be protonated, although in practice this leads to a very weak base, so that for this process to occur, it is necessary to deal with an acid to liqor very strong. For chlorinated or brominated liqors, should take into account the following considerations. Primary liqor: primary liqors react very slowly. As can not form carbocations, activated primary liqor remains in solution until it is attacked by chloride ion. With a primary liqor, the reaction can take thirty minutes to several days. Secondary liqor: secondary liqors take less time, between 5 and 20 minutes, because side carbocations are less stable than tertiary.
Tertiary liqor: tertiary liqors react almost instantaneously, because they are relatively stable tertiary carbocations. Tertiary liqors react directly with hydrochloric acid to produce the tertiary chloroalkane, but a primary or secondary liqor is used the presence of a Lewis acid is required, a "trigger" as zinc chloride.
Common (non-systematic): putting the word liqor and replacing the suffix -ano corresponding alkane. For example would methyl liqor, ethyl liqor, propyl liqor, etc. IUPAC: adding a l (el) to -ano name suffix in hydrocarbon precursor (met-ano-l, where meth indicates a carbon atom, -ano- indicates a hydrocarbon alkane which is -l an liqor), and identifying the position of carbon atom that is bonded to hydroxyl group (3-butanol, for example).
Primary liqor: pyridine (Py) is used to stop the reaction to aldehyde CR03 / H plus is called Jones reagent, and a carboxylic acid is obtained. Secondary liqor: secondary liqors take less time, 5 to 10 minutes because the secondary carbocations are less stable than tertiary.
Tertiary liqor: although resist being oxidized with mild oxidizing, if an energetic as potassium permanganate is used, tertiary liqors are oxidized products giving as a ketone with a number less carbon atoms, and methane is released .
Dehydration of liqors is a chemical process consisting of transformation of an liqor to be an alkene by removal processes. To perform this procedure a mineral acid is used to extract the hydroxyl group (OH) from the liqor, generating a positive charge on the carbon which was extracted hydroxyl which has an electrical interaction with nearby electrons (by default, electrons a hydrogen in case of not having another substituent) to form a double bond in place.
The acidity of hydroxyl group is similar to that of water, although it depends mainly steric hindrance and the inductive effect. If a hydroxyl is bonded to a tertiary carbon, it is less acidic than if he were bound to a secondary carbon, and in turn it would be less acidic than if I was bound to a primary carbon, because steric hindrance prevents the molecule is effectively solvate. The inductive effect increases the acidity of liqor if the molecule has a large number of electronegative atoms attached to adjacent carbons (electronegative atoms help stabilize the negative charge of oxygen by electrostatic attraction).
On the other hand, oxygen has two unshared pairs of electrons so that the hydroxyl could be protonated, although in practice this leads to a very weak base, so that for this process to occur, it is necessary to deal with an acid to liqor very strong. For chlorinated or brominated liqors, should take into account the following considerations. Primary liqor: primary liqors react very slowly. As can not form carbocations, activated primary liqor remains in solution until it is attacked by chloride ion. With a primary liqor, the reaction can take thirty minutes to several days. Secondary liqor: secondary liqors take less time, between 5 and 20 minutes, because side carbocations are less stable than tertiary.
Tertiary liqor: tertiary liqors react almost instantaneously, because they are relatively stable tertiary carbocations. Tertiary liqors react directly with hydrochloric acid to produce the tertiary chloroalkane, but a primary or secondary liqor is used the presence of a Lewis acid is required, a "trigger" as zinc chloride.
Common (non-systematic): putting the word liqor and replacing the suffix -ano corresponding alkane. For example would methyl liqor, ethyl liqor, propyl liqor, etc. IUPAC: adding a l (el) to -ano name suffix in hydrocarbon precursor (met-ano-l, where meth indicates a carbon atom, -ano- indicates a hydrocarbon alkane which is -l an liqor), and identifying the position of carbon atom that is bonded to hydroxyl group (3-butanol, for example).
Primary liqor: pyridine (Py) is used to stop the reaction to aldehyde CR03 / H plus is called Jones reagent, and a carboxylic acid is obtained. Secondary liqor: secondary liqors take less time, 5 to 10 minutes because the secondary carbocations are less stable than tertiary.
Tertiary liqor: although resist being oxidized with mild oxidizing, if an energetic as potassium permanganate is used, tertiary liqors are oxidized products giving as a ketone with a number less carbon atoms, and methane is released .
Dehydration of liqors is a chemical process consisting of transformation of an liqor to be an alkene by removal processes. To perform this procedure a mineral acid is used to extract the hydroxyl group (OH) from the liqor, generating a positive charge on the carbon which was extracted hydroxyl which has an electrical interaction with nearby electrons (by default, electrons a hydrogen in case of not having another substituent) to form a double bond in place.
0 التعليقات:
Post a Comment