**1. Introduction**

The bridge between chemistry and the day-to-day human life is always growing wider and stronger, and acetic acid is one of the perfect examples. Acetic acid is a clear liquid with a pungent odour, sharp taste, melting point of 16.73°C and boils at 117.9°C. Acetic acid, traditionally known as 'vinegar' is widely used as a food preservative, first discovered (c. 5000 BC) when unattended grape juice turned into wine. A famous physician Hippocrates II (c. 420 BC) used acetic acid to clean the wounds [1]. With direct and indirect applications of acetic acid, it has diversified into several chemical sectors such as food, pharma, chemical, textile, polymer, medicinal, cosmetics etc. Since then, acetic acid is proven to be a multi-application chemical building block resulting in ever-increasing demand. The production of acetic acid is expected to reach 18 million ton with an average growth of 5% per year [2, 3].

The overall routes for production and the applications of acetic acid are shown in **Figure 1**. Currently, the manufacturing demand is fulfilled via two main

production routes, which are chemical and fermentative. Among the chemical manufacturing processes, the key processes are Cavita process (carbonylation of methanol), oxidation of aldehyde and oxidation of ethylene. The major players are BP chemicals and BASF, which follow carbonylation route. The major consumption of acetic acid mainly comes from the preparation of vinyl acetate monomer (VAM), acetic anhydride and C1-C4 acetates and it is used as a solvent in synthesis of terephthalic acid (PET). VAM is one of the main ingredients used in polymer industry with application as emulsifier, resins, as intermediate in surface coating agent, acrylic fiber and polymer wires. It is also used in textile industry to generate synthetic fibers as a result of condensation reaction. The other condensation reaction of acetic acid produces acetic anhydride used as typical acetylation agent, which is subsequently utilized to produce cellulose acetate, used in synthetic textiles and for silver-based photographic films. Most derived esters of acetic acid are ethyl acetate, n-butyl acetate, isobutyl acetate and propyl acetate, which are frequently used as solvents for inks, paints and coatings. Glacial acetic acid is an excellent polar protic solvent that is frequently used as a solvent for recrystallization to purify organic compounds. Several researchers are working on developing a sustainable process with the simple design to produce acetic acid that meets current demand.

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**Figure 2.**

*Production Pathways of Acetic Acid and Its Versatile Applications in the Food Industry*

the production of acetic acid with carbonylation process [4].

come such as edible and non-edible antimicrobial coating [5, 6].

Several homogeneous as well as heterogeneous catalytic systems are reported for

Acetic acid produced via fermentation route is mainly utilized in the food industry in the form of vinegar. Use of vinegar is more diversified these days, with more innovative ways to adjust and suit the current lifestyle and food culture. The different concentrations of acetic acid are used to sharpen the taste of food with a longer shelf life period and as a food preservative. Some new applications have also

This chapter reviews the current commercial processes for the synthesis of acetic acid to meet an ever-increasing global demand. The chapter also gives insight into the pros and cons associated with the process available and then how should we design a sustainable strategy to develop a simple commercial process. Further, the state of art to produce vinegar is discussed with exploitation as a multiapplication

Acetic acid is mainly produced via chemical route that involves homogeneous as well as heterogeneous catalytic methods. The carbonylation of methanol via Monsanto process is the most adopted route, which further evolved as Cavita process with a choice of catalysts and process intensification. In the recent decade, the fermentative approach has also gained attention; however the commercial approach is not established yet. The current trends in sustainable manufacturing demand an urgent paradigm shift to develop and pursue more sustainable routes to reduce environmental burden. An approach is also made with the development of membrane-based technology, which offers a very simple design with eco-friendly

Carbonylation process is a most employed commercial route for synthesis of acetic acid, also known as Monsanto process (**Figure 2**). Methanol and carbon monoxide are reacted in liquid phase in the presence of rhodium (Rh)-based catalyst at 150–200°C temperature and 30–50 bar pressure to produce acetic acid with 95% selectivity and 5% side products such as formic acid and formaldehyde [8]. Hydrogen iodide is used as an alkali promoter in this process. The reaction proceeds in liquid phase with methyl acetate as solvent using homogeneous catalyst. Controlled amount of water is required for the reaction, which is generated *in situ* by reaction of methanol with hydrogen iodide. The rate of reaction in the Monsanto process depends on the concentration of water. CO2, H2 and methanol are obtained

*DOI: http://dx.doi.org/10.5772/intechopen.92289*

tool in the modern food industry.

**2. Production of acetic acid**

production [7].

**2.1 Conventional process**

*2.1.1 Methanol carbonylation process*

*Production of acetic acid by carbonylation method.*

**Figure 1.**

*Commercial routes for synthesis of acetic acid and applications.*

#### *Production Pathways of Acetic Acid and Its Versatile Applications in the Food Industry DOI: http://dx.doi.org/10.5772/intechopen.92289*

Several homogeneous as well as heterogeneous catalytic systems are reported for the production of acetic acid with carbonylation process [4].

Acetic acid produced via fermentation route is mainly utilized in the food industry in the form of vinegar. Use of vinegar is more diversified these days, with more innovative ways to adjust and suit the current lifestyle and food culture. The different concentrations of acetic acid are used to sharpen the taste of food with a longer shelf life period and as a food preservative. Some new applications have also come such as edible and non-edible antimicrobial coating [5, 6].

This chapter reviews the current commercial processes for the synthesis of acetic acid to meet an ever-increasing global demand. The chapter also gives insight into the pros and cons associated with the process available and then how should we design a sustainable strategy to develop a simple commercial process. Further, the state of art to produce vinegar is discussed with exploitation as a multiapplication tool in the modern food industry.
