Alcohols are
widely used as solvents, fuels and chemical raw materials. Generally, hydroxyl
group compounds are polar, which trends to promote solubility in water. But the
carbon chain resist to solubility in water. Short chain alcohols (methanol,
ethanol, and propanol) in which the hydroxyl group predominates are miscible in
water. Butanol is moderately soluble because of the balance between the two
opposing solubility trends. Higher alcohols are practically insoluble in water
because of the hydrocarbon chain's trend is stronger. Alcohols are "protic"
solvents. Protic refers to a hydrogen atom attached to an electronegative atom,
oxygen. Polar protic solvents are compounds that can be represented by the
general formula ROH of which water (H2O), methanol
(CH3OH) and acetic acid
(CH3COOH) are examples.
Water-soluble alcohols, low-molecular weight products, are solvents for the
manufacture of coatings, dyes and inks, plastics, flavorings, personal-care
products, pharmaceuticals, and cleaners. The higher alcohols, slightly soluble
in water or insoluble, can provide the proper balance of target properties when
solvent-based solvents are formulated for desired viscosity, flowing and
leveling, and curing rate and can be used as coupling agents in waterborne
coatings.
Alcohols are
very weak acids as they lose H+ in the hydroxyl group. Alcohols
undergoes dehydration reaction which means the elimination of water molecule
replaced by a pi bond between two adjacent carbon atoms to form alkenes under
heating in the presence of strong acids like hydrocloric acid or phosphoric
acid. Primary and secondary alcohols can be oxidized to aldehydes and ketones
respectively. Carboxylic acids are obtained from oxidation of aldehydes.
Oxidation in organic chemistry can be considered to be the loss of hydrogen or
gain of oxygen and reduction to gain hydrogen or loss of oxygen. Tertiary
alcohols do not react to give oxidation products as they have no H attached to
the alcohol carbon. Alcohols undergoes important reactions called nucleophilic
substitution in which an electron donor replaces a leaving group, generally
conjugate bases of strong acids, as a covalent substitute of some atom. One of
important reaction of alcohol is condensation. Ethers are formed by the
condensation of two alcohols by heating with sulfuric acid; the reaction is one
of dehydration. Almost infinite esters are formed through condensation reaction
called esterification between carboxylic acid and alcohol, which produces water.
Alcohols are important solvents and chemical raw materials. Alcohols are
intermediates for the production of target compounds, such as pharmaceuticals,
veterinary medicines, plasticizers, surfactants, lubricants, ore floatation
agents, pesticides, hydraulic fluids, and detergents.
Carbinol is a
primary alcohol with general formula RCH2OH. In carbinol
nomenclature system, the term of carbinol is methanol itself and other groups
are considered to have replaced one of the methanol hydrogen atoms to describe
larger alcohols as derivatives of carbinol. This nomenclature system is
particularly useful when the groups attached to the methanol carbon are large,
aromatic, and cyclo groups. Benzyl alcohol is
called phenylcarbinol or
benzenecarbinol while benzyl carbinol is phenylethyl alcohol.
1-Butanol, a
four carbon straight chain alcohol, is a volatile, clear liquid with a strong
alcoholic odor; boils at 118 C, miscible with water. It is a highly refractive
compound which corrodes some plastics, and rubbers. It is miscible with many
organic solvents, and incompatible with strong oxidizers. It is flammable
strongly with a luminous flame. It is used as a direct solvent and as an
intermediate in the manufacture of other organic chemicals (e.g. Butyl acrylate
and methacrylate, glycol ethers, butyl acetate, direct solvent use,
plasticizers, amino resins, miscellaneous, including butylamines). Butanol and
its derivatives continue to benefit from the long-term growth of water-based
coatings formulations of all kinds. Analysts estimate that nearly 70 percent of
all exterior architectural paints and as much as 85 percent of interior paints
are now water-based. For butanol, butyl acrylate and butyl acetate, become
increasingly important. Uses include :
- Solvent for
paints, coatings, varnishes, resins, gums, dyes, camphor, vegetable oils, dyes,
fats, waxes, resins, shellac, rubbers, and alkaloids.
- Solvent in
the purification of polyolefins, Alkyd resin coatings
- Intermediate
in manufacturing other chemicals, esters of herbicides pharmaceuticals,
veterinary medicine
- Swelling
agent in textiles
- Manufacturing safety glass, hydraulic fluids, and
detergent formulations.
- Formulating
brake fluids.
- Extractant
in manufacturing antibiotics, vitamins, and hormones
- Manufacturing garments from polyvinyl butyral-coated
fabric,
- Cement
additive to increase the fineness
- Ore
floatation agents.
- Melamine
formaldehyde resins.
Methoxybutanol's
application is similar with n-butanol as a low volatile
solvent, but better dissolving is expected. Methoxybutanol
is used with n-butyl acetate to improve dissolving power,
drying time, and flow.
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