Published December 2014
The main pyridines include pyridine, alpha-picoline, beta-picoline, gamma-picoline and 2-methyl-5-ethylpyridine (MEP). Pyridine and beta-picoline accounted for 80% of world consumption of pyridines in 2014.
Pyridines are characterized by having a six-membered heterocyclic aromatic ring, consisting of five carbon atoms and one nitrogen atom. In addition to pyridine, the major pyridine bases include alpha-picoline, beta-picoline and gamma-picoline. Pyridine and the picolines are colorless liquids with strong odors. They are soluble in both water and alcohol, and form azeotropes with water, permitting separation by distillation.
Synthetic processes account for the majority of world production of pyridines. These processes allow for the production of a more consistent product and ensure a reliable supply over the natural sources. The availability of naturally derived pyridines is grossly insufficient to meet demand. The majority of synthetic processes do not yield a unique product but produce a mix of bases, the composition of which can be somewhat influenced by specialized technology, reaction conditions and additives.
The following pie chart shows world consumption of pyridines:
Agricultural chemicals, mainly the nonselective contact herbicide paraquat, account for most consumption of pyridine; however, there is also some demand for piperidine and 2-chloropyridine in some regions. beta-Picoline, which is used to produce niacinamide/niacin (vitamin B3), is forecast to grow at an average annual rate of 4–5%, as a result of demand for niacinamide/niacin in developing regions such as Asia for use in animal feed (mainly poultry and dairy cattle). 2-Methyl-5-ethylpyridine (MEP) is used nearly entirely to produce niacin. The largest market for alpha-picoline is 2-vinylpyridine (2-VP); most 2-VP is used as a component of styrene-butadiene-2-vinylpyridine terpolymer latexes (SBV latexes), which are used as tire cord adhesives and in other adhesives for bonding textiles to elastomers.
In the coming years, pyridines production and consumption growth will continue to be driven by Asia, in particular China and India. In China, pyridines growth will be supported by increased niacinamide production and, to a lesser extent, demand for agricultural chemicals. New niacinamide capacity and niacinamide plant expansions are expected to come onstream in the next few years. Likewise, in India, new niacinamide capacity is expected to be completed in the next year or so. Improving living standards and increased production of both animal feeds (primarily for poultry and dairy cattle) and agricultural crops are the main factors behind growth in niacinamide/niacin and paraquat, respectively.