Acetic Acid Through Microwave Assisted Pyrolysis (MAP) of Residual/Waste Biomass as a Contribution to Circular Economy

Acetic acid may be obtained by fermentation of ethanol, but industrial processes for the production of acetic acid, are mainly using mineral oil as starting compound, the most importants through methanol carbonylation. A possible alternative to these processes, using natural and bio-renewable raw materials, may be the microwave assisted pyrolysis of residual/waste biomass. A bio-oil is formed, from which acetic acid together with other important bio-organic compounds are the raw materials for a bio-refinery. In this chapter, a review of some applications of microwave assisted pyrolysis for the production of acetic acid, using biomasses such as cellulose, lignin, wood pellets, wood residue from municipal solid waste, biomass residues from agricultural productions, or biomass removed as invasive products present in fields were tested. All these products, when pyrolyzed through a microwave assisted pyrolysis process gave a gas, a bio-oil, and a bio-char In these chapter the bio-oils formed from different biomasses as well as from different reaction conditions using the same biomass are reported. The acetic acid present in the bio-oil may be separated and utilized, and an environmental friendly scheme for this separation is reported. Other interesting products may be separated from the bio-oil and finally the residue may be employed as fuel. Obviously this acid has the same characteristics of the product obtained by mineral oil so it may be directly employed for the production of new materials thus reducing both the request of mineral oil and the carbon dioxide formed during the processing and giving a strong contribution to the circular economy.