Acetic Anhydride: A Much-Needed Versatile Intermediary in the Chemical Sector
Acetic anhydride or ethanoic anhydride is a clear, colorless liquid with a very pungent, vinegar-like odour that occurs due to its reaction with moisture in the air. Acetic anhydride can be dissolved in regular organic solvents and is completely miscible with diethyl ether. However, with elevated temperatures its reaction with water, steam, and alcohols can be extremely violent and exothermic. Reaction with water along with mineral acids may become explosive as well. Acetic anhydride is widely used in synthesis of chemical products or as an intermediate owing to its dehydrating and acetylating properties.
Acetic anhydride is synthesized from ketene route process using glacial acetic acid as a raw material, wherein ketene is obtained via dehydration of acetic acid or through decomposition of acetone. It can also be obtained through oxidation of acetaldehyde yielding acetic acid. Acetic anhydride can also be produced by carbonylation of acetate, a process similar to the Monsanto acetic acid production process. Furthermore, it can also be produced from acetic acid recovered from cellulose acetate, one of the largest downstream consuming products of acetic anhydride. Acetic anhydride is used as a solvent in fungicides as well as dyes. It is also used in wide range of industries including pharmaceuticals, electronics, perfume & fragrances, crop protection chemicals, paints & coatings, and food ingredients.
Cellulose Acetate and Pharmaceuticals Continues to be the Largest Consumers
In 2019, the estimated demand for acetic anhydride stood at 2.5 million tons. Globally, cellulose acetate flake is the largest application segment for acetic anhydride. These flakes are used to produce filter tows, which are mainly consumed in cigarettes, and in the production of textile fibers. Growing demand for longer filter cigarettes to reduce tar and nicotine consumption is expected to drive demand for filter tows over the coming years. Increasing demand for filtered cigarettes along with rising sales of sophisticated filters in certain parts of the world is anticipated to boost the demand for cellulose acetate flakes and in turn the demand for acetic anhydride over the coming years.[MG1] However, transition to e-cigarettes coupled with stringent government policies and regulations related to smoking are likely to thwart market growth
Pharmaceutical has emerged as another major end user of acetic anhydride. It is used in manufacturing a variety of pharmaceutical drugs and intermediates. Acetic anhydride is a key material to produce acetylsalicylic acid (aspirin), paracetamol, acetaminophen, sulfa drugs, I-bruphen, and a certain range of vitamins and hormones. It is also used to produce tetraacetylethylenediamine (TAED), a commonly used bleach activator in laundry detergents and for paper and pulp industry.
Wood Acetylation to Offer Renewed Growth in the Acetic Anhydride Market
Wood acetylation or acetylated wood is a very old concept and was first commercially produced in Japan in early 80’s. Water can bring a whole lot of issues while preserving wood such as splintering, swelling, warping, etc. Furthermore, there are challenges related to rotting that can lead to fungi and insect attacks (such as termites). To protect, wood needs to be treated with wood preservation chemicals such as alkaline copper quaternary (ACQ), borates, acid copper chromate (ACC), copper azole, etc. These chemicals only treat the wooden surface, leaving chemicals that eventually leach out over the time.
Acetic anhydride is used as a reagent for wood acetylation, wherein it reacts with the hydroxyl groups on large molecules such as lignin and hemicellulose in the plant cell wall. Basically, the wood is soaked in acetic anhydride to offer wood an effective resistance to moisture, fungi, and insects as compared to other wood preservation chemicals. Furthermore, acetylated wood is also more durable as compared to pressure treated wood. In the past few years, there has been growing demand for wood acetylated timber/wood across major regions such as Europe and Asia, this is anticipated to offer renewed growth to acetic anhydride market, which is traditionally reliant on cellulose acetate and the pharmaceutical industry for its growth.
Asia Pacific, Led by China, to Remain the Largest Market
Asia Pacific is one of the largest consumers of acetic anhydride. China is the leading consumer in the region and is expected to offer bright opportunity, especially looking at the growth of the pharmaceutical industry in the country. Being the region’s largest producer, China is anticipated to diversify its production to other applications including TAED and polytetramethylene ether glycol (PTMEG). India is also driving the growth of acetic anhydride as the Indian government data suggests the domestic pharmaceutical industry reached revenue of US$ 20 Bn in 2019.
According to a survey, India’s pharmaceutical industry is expected to grow 3x over the coming decade. As a prominent player in the pharmaceutical sector, the country is rapidly growing its presence in the generic sector. Acetic anhydride is a key ingredient used in generic medicines such as sulfa drugs, paracetamol, and aspirin. The market also stands to benefit as acetic anhydride is increasingly being used in the consumption of basic dyes and pigments. India has also showed a steady cigarette consumption as opposed to countries such as Japan, China, and South Korea who have experienced a slight decline in the recent past.
Meanwhile, Europe is projected to demonstrate stable growth. It is one of the mature markets and is expected to offer limited growth opportunities especially in cellulose acetate applications. The region is witnessing a shift in consumption patterns of tobacco and related products as various regulations have been imposed by the regulatory authorities. In 2020, EU enforced a new law on selling flavoured cigarettes in the region, which is anticipated to thwart growth in the region. Even other countries such as the U.S. are also likely to ban menthol cigarettes over the next couple of years, thus creating a huge challenge for producers in the country as majority of the acetic anhydride is consumed captively for cellulose acetate production. Growing demand from pharmaceutical industry and rise in production of TAED are likely to offer bright prospect for acetic anhydride in these regions.
Big Integrated Companies to Dictate the Acetic Anhydride Market
The acetic anhydride market is highly aggressive and consolidated. Integrated companies such as Celanese, Eastman, China National Petroleum Corporation, INEOS, and Jubilant Ingrevia have strong presence in merchant market. The Middle East and Asia Pacific region are anticipated to lead with new capacity additions as demand for pharmaceutical and other chemical applications in these regions grows.
In January 2021, INEOS completed the acquisition of BP Chemical’s global Aromatics and Acetyl businesses for US$ 5 Bn. The acquisition includes assets, technology, and licenses, as well as related interests such as acetylated wood developer Tricoya and recycling technology BP Infinia. The acquisition will boost the acetyls product portfolio as well as geographical presence of INEOS in this business. This deal is likely to mark a definitive shift in the competitive landscape of global acetyl business.