In the presence of an acid catalyst (typically, sulfuric acid) ethanol reacts with carboxylic acids to produce ethyl esters. The two largest-volume ethyl esters are ethyl acrylate (from ethanol and acrylic acid) and ethyl acetate (from ethanol and acetic acid).

Ethyl acetate is a common solvent used in paints, coatings, and in the phar­maceutical industry. The most familiar application of ethyl acetate in the household is as a solvent for nail polish. A typical reaction that synthesizes ethyl acetate is based on esterification:

C2H5OH + CH3COOH = C2H5OOCCH3 + H2O

This chemical reaction follows very closely a second-order reaction kinet­ics, an often-used example problem for second-order elementary reactions in chemical reaction engineering textbooks.

Recently, Kvaerner Process Technology developed a process that produces ethyl acetate directly from ethanol without acetic acid or other cofeeds. Considering that both acetic acid and formaldehyde can also be produced from ethanol, this ethanol-to-ethyl acetate process idea is quite innovative and significant. The Kvaerner process allows the use of fermentation etha­nol, produced from biorenewable feedstock, as a sustainable single-source feed, which is remarkable. Furthermore, the process elegantly combines both dehydrogenation and selective hydrogenation in its process scheme, thus producing hydrogen as a process by-product which makes the process eco­nomics even better.

Ethyl acrylate, which is synthesized by reacting ethanol and acrylic acid, is a monomer used to prepare acrylate polymers for use in coatings and adhe­sives. Ethanol is a reactant for ethyl-t-butyl ether, as is the case for methanol to methyl-t-butyl ether. ETBE is produced by reaction between isobutylene and ethanol as

C2H5OH + CH3C(CH3)=CH2 ^ C(CH3)3 OQH5

Vinegar is a dilute aqueous solution of acetic acid prepared by the action of Acetobacter bacteria on ethanol solutions. Ethanol is used to manufacture ethylamines by reacting ethanol and ammonia over a silica — or alumina-sup­ported nickel catalyst at 150-220°C. First, ethylamine with a single amino group in the molecule is formed and further reactions create diethylamine and triethylamine. The ethylamines are used in the synthesis of pharmaceu­ticals, agricultural chemicals, and surfactants.

Ethanol can also be used, instead of methanol, for transesterification of tri­glycerides in biodiesel production using vegetable oils or algae oils, as dis­cussed in Chapter 2. In the United States, methanol is currently more popularly used for this purpose, mainly due to its more favorable process economics.

In addition, ethanol can be used as feedstock to synthesize petrochemicals that are also derived from petroleum sources. Such chemicals include ethyl­ene and butadiene, but are not limited to these. This option may become via­ble for regions and countries where the petrochemical infrastructure is weak but agricultural produce is vastly abundant. This is particularly true for the times when petroleum prices are very high. Ethanol can also be converted into hydrogen via reforming reaction, that is, chemical reaction with water at an elevated temperature typically with the aid of a catalyst. Even though this method of hydrogen generation may be economically less favorable than either steam reforming of methane or electrolysis, the process can be used for special applications, where specialty demands exist or other infrastruc­ture is lacking.

More recently, supercritical water reformation of crude ethanol beer was developed for hydrogen production [41]. The process utilizes super­critical water (T > 374 C and P > 218 atm) functioning both as a highly energetic reforming agent and as a supercritical solvent medium, thus effectively eliminating the service of any noble metal catalyst or the need of pure ethanol. Furthermore, its direct noncatalytic reformation of unpu­rified crude ethanol beer alleviates the need for any energy-intensive pre­distillation or distillation of a water-ethanol solution, thereby achieving overall energy savings.

Poly(lactic acid) or polylactide (PLA) is a thermoplastic aliphatic polyester derived from cornstarch. Poly(lactic acid) is one of the leading biodegradable polymers, which is derived from renewable biosources, more specifically corn in the United States. A variety of applications utilizing poly(lactic acid) are being developed, wherever biodegradability of plastic materials is desired. PLA can be used by itself, blended with other polymeric materials, or as composites. As biodegradable polymer technology further develops, the PLA market is also expected to grow and so is the cornstarch market.