Alkylphenols are a group of compounds derived from phenol, in which one or more hydrogen atoms in the aromatic ring are substituted with an alkyl group. In industry, compounds from this group are synthesised in the liquid phase in the presence of an ion-exchange resin serving as a catalyst. The reaction products are mainly the para isomer, which has an alkyl group in the para position, relative to the hydroxyl group, and small amounts of the ortho isomer. Side products also form during the synthesis reaction, mainly dialkylphenols and small amounts of lower and higher alkylphenols.
The production process is run continuously at an appropriate temperature, using an excess of phenol to effect high selectivity and limit the generation of side products. The post-reaction mixture is subjected to separation by vacuum distillation.
A boon of this production method is a low consumption of raw materials and utilities, as well as no wastewater, so no damage to the environment is caused.
The process is characterised by the following advantages:
high product quality,
high reaction selectivity and efficiency,
long catalyst life,
low amounts of waste products, wastewater and exhaust gases.
Alkylphenol examples and applications
Depending on the alkene used in the process, it is possible to obtain phenol derivatives with short or long alkyl chains. Long-chain alkylphenols are, for example, nonylphenol and dodecylphenol.
Nonylphenol and its applications
Nonylphenol (CAS: 84852-15-3) is a colourless, oily liquid with a characteristic odour. It is a mixture of isomers, containing primarily p-nonylphenol. Nonylphenol is soluble in aliphatic alcohols, ketones, esters, and aliphatic hydrocarbons, and is very poorly soluble in water.
Nonylphenol finds use in the production of paints and binders, printing inks, varnishes and powder-based paints, and as a semi-finished product in the manufacturing of fire retardants. It is also used as a semi-finished product in the production of ethoxylates, which in turn are used to manufacture non-ionic surface active agents. It is perfect for the production of epoxy and phenol resins, as an additive to greases, in the production of plant protection agents, and in the tyre and extraction industries. It is also a semi-finished product in the manufacturing of propoxylates, which are used to make rigid foams.
Dodecylphenol properties and applications
Dodecylphenol (CAS: 121158-58-5) is a thick, viscous liquid with a lightly yellowish colour and a characteristic odour. It is a mixture of isomers, containing mainly p-dodecylphenol, which is soluble in aliphatic alcohols, ketones, esters, and aliphatic hydrocarbons, and at the same time is very poorly soluble in water.
Dodecylphenol also finds use as an additive for oils and fuels, various types of specialist resins, paints, varnishes, coating resins, and as a component of additives for the extraction industry.
