Everyone is familiar with acetic acid when it comes to food - it can be found in pickles, spreads, preserves and much more. However, only about three percent of the acetic acid produced worldwide is used as table vinegar or vinegar essence. So what is the large rest used for and which industries are affected by the extreme shortage in Europe - and how could it come to this in the first place that prices have risen three to four times?
The main end uses and their applications
Acetic acid is an important basic chemical with applications in various downstream industries and numerous industrial chemical processes. The chemical is an excellent solvent for inorganic and organic compounds and is often used as a reactant. Vinyl acetate monomer (VAM) is the largest end use for acetic acid, followed by purified terephthalic acid (PTA), ethyl acetate and acetic anhydride. Other uses include monochloroacetic acid and butyl acetates.
1. Vinyl acetate monomer (VAM)
VAM (vinyl acetate monomer) consumes a large proportion of the acetic acid produced worldwide, accounting for 35.5% (2019). The main function of VAM is in the production of polyvinyl alcohol and polyvinyl acetate, which cumulatively account for more than 80 per cent of global VAM use.These polymers find their application in the form of liquid dispersions, dispersible powders, solid resins and solutions, particularly as binders in the construction, paints and coatings sectors and as raw materials for the adhesives, paper and textile industries.
2. Purified terephthalic acid (PTA)
Acetic acid also serves as a solvent in the production of terephthalic acid by liquid phase oxidation. PTA is mainly used to produce polyester coating resins used in the manufacture of automobiles, appliances, coil coatings, general metal applications and many more. A high proportion of PTA is further processed into polyethylene terephthalate (PET), which in turn is used in textiles, plastic bottles and packaging materials. PTA is also an important intermediate in the production of poly ethers, fragrances and medicines.
3. Acetate esters
Another important application of acetic acid involves the formulation of acetate esters. Some of these esters, such as linalyl acetate, are used as fragrances or flavourings. Ethyl acetate (ETAC) is the most widely used solvent in many industries (inks, paints and varnishes, adhesives, packaging, coatings automotive, printing chemicals). Butyl acetate (BUTAC) is also a very common solvent used in paints and varnishes.
4. Acetic anhydride
Another significant part of acetic acid is converted to acetic anhydride, which is mainly used for the synthesis of aspirin, acetylation of salicylic acid, cleaning of oil spills, wood preservation applications and more. By reacting acetic anhydride with cellulose, the plastic cellulose acetate (acetyl cellulose) is produced, which is then further processed into textile fibres (artificial silk), coatings, cigarette filters and other plastic products. Cellulose acetate films are also used in the optical layers of computer flat screens, mobile phone displays and other LC displays.
5. Other applications
- Food: Food-grade acetic acid is used as an acidifier for food (E 260). It is used in the production of vinegar essences (e.g. salad dressings) and preserves (pickles, mustard, fish, vegetables, fruit, etc.). Salts of acetic acid are used as a preservative for food (e.g. in baked goods). Various dairy products are also made using acetic acid. Pickling and washing of fresh meat is also done with the help of acetic acid.
- Pharmaceutical industry: Pharmaceutical-grade acetic acid is not only used in medicines such as aspirin and paracetamol. The acid is also suitable as a disinfectant, a cautery for warts and corns, a blood circulation stimulant and much more.
- Perfume and cosmetics: In the perfume industry, chemically pure acetic acid is primarily used for the production of acetic acid esters (e.g. borneol and geraniol), which in turn are used as solvents for cosmetics and perfumes (fragrances). Acetic acid is also used to acidify hygiene and cosmetic products, for example for exfoliation.
- Textile and leather industry: In addition to the production of textile fibres and fabrics, acetic acid is used to adjust the pH value to the desired value in dyeing processes and for the production of handle refining and impregnating agents. In the leather processing industry, acetic acid is used to decalcify hides.
- Rubber industry: To obtain rubber, the natural latex is coagulated with acetic acid in low concentrations. About 70 percent of the rubber is used to produce car tyres. The rest is used to manufacture a wide variety of latex products, e.g. moulds, sealing profiles, foams, gloves, balloons or erasers.
- Electroplating industry: As pickling acid and in electrolytic metal deposition baths.
- Photographic industry: In the photographic laboratory practice of analogue photography, diluted acetic acid (3-5 %) is used for pH adjustment (stop baths, etc.).
- Oil exploration: Auxiliary in drilling muds.
- Household chemistry: In terms of quantity, applications in the household as a cleaning agent for limescale deposits are of minor importance.
6. Conclusion: Bottleneck
Recently, the shortage has also become apparent in food production. In addition to the already existing citric acid shortage, this could lead to a threat to food production. The situation in the pharmaceutical industry could also become critical if there is a shortage of acetic acid for the production of important drugs, especially mass drugs such as aspirin.
The construction industry is also struggling with drastic price increases for many raw materials that are necessary for the production of construction chemical products. These include important aggregates such as polymers and latex, paints, adhesives and coatings - materials for whose production acetic acid is essential.
The bottleneck is now also strongly felt by manufacturers of rubber and plastic goods, where there is a
shortage of almost all raw materials. This is then felt by other sectors where there is a shortage of packaging material. With full order books, many companies in trade, commerce and industry will soon no longer be able to produce.
What are the causes of the acetic acid shortage?
The market size for acetic acid was estimated at nearly 16,000 kilotonnes in 2020, with China producing 54% of global production, followed by the United States at 17%. About 75% of global acetic acid capacity is produced by the methanol-carbon monoxide process, also known as carbonylation of methanol. Global production of acetic acid is thus largely dependent on petrochemical feedstocks such as methanol.
1. Oil production grows only slowly
Europe gets most of its acetic acid from the USA, which produces acetic acid using the methanol-carbon monoxide process. The collapse in oil production, as a result of the global shutdowns and reduced fuel consumption, has led to an extreme shortage of petrochemicals such as methanol. As a result, acetic acid production has also been reduced significantly.
Most recently, oil production has been burdened primarily by the Corona situation in India and Japan, as restrictions on mobility have been enacted in both countries. In other countries of the world, such as the USA and China, the economy is doing better, which also increases the demand for crude oil again. According to OPEC, however, there are few signs of a recovery in US oil production.
2. Low exports from the USA as a result of the winter storm
The shortage of acetic acid supply in Europe was exacerbated by the shutdown of most plants in the US Gulf in mid-February 2021 following the winter storm. Several major suppliers put European customers on allocation as a result of the freeze and reduced supply volumes in contracts and on the spot market. In the meantime, the production of US acetic acid is slowly starting up again, but the available quantities for exports to Europe remain low. This is due to low production rates caused by problems in the procurement of raw materials such as methanol and ongoing repair work.
3. Imports from Asia difficult at present
As production in the western hemisphere is quite scarce, suppliers are trying to source acetic acid from Asia - which is a challenge at the moment. This is due to high demand in Asia, shipping delays caused by the blockade of the Suez Canal and a series of plant breakdowns in China. Restocking in India and supply shortages in Europe have further fuelled the price rally.
4. Containers remain in short supply
The situation is further constrained by long transportation lead times and limited availability of sea and land freight capacity. The maritime supply chain remains fragile, containers are in short supply and freight rates are still going up. This drives up costs for transport companies and will inevitably reach end consumers.
Executives at AP Moller-Maersk A-S, the world's leading container carrier, see no decline in ocean freight rates for the rest of 2021. And even then, they do not expect a return to the low-cost ocean freight service of the last decade.
How are availability and prices developing for the most important derivatives?
Prices for acetic acid are mainly determined by the prices for raw materials and methanol as well as the downstream demand for its derivatives.
- VAM: Price increases due to strong supply shortages will persist as demand remains robust and there is no slowdown as a result of rising VAM prices.
- PTA: European supply of purified terephthalic acid (PTA) is very tight due to limited domestic production and continued limited import availability. Demand for PTA remains strong. Much will depend on the opening of the economy and events that traditionally support increased sales of downstream PET products.
- ETAC: European spot prices for ethyl acetate (Etac) are stable at high levels. However, supply remains tight due to limited acetic acid availability.
- BUTAC: European spot prices for butyl acetate (Butac) are currently stable. However, supply remains very tight due to the force majeure of a major European producer, lack of imports and shortages of upstream products such as propylene, n-butanol and acetic acid.
Conclusion: Effects of the acetic acid shortage
Many sectors, and especially the chemical industry, are currently experiencing an extraordinary shortage of raw materials, accompanied in some cases by massive price increases of important upstream products. The shift in the flow of goods has now become so acute that even the demand for a basic chemical such as acetic acid can no longer be fully covered.
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