Propionic acid, manufacture

Anhydrous Acetic Acid. In the manufacture of acetic acid by direct oxidation of a petroleum-based feedstock, solvent extraction has been used to separate acetic acid [64-19-7] from the aqueous reaction Hquor containing significant quantities of formic and propionic acids. Isoamyl acetate [123-92-2] is used as solvent to extract nearly all the acetic acid, and some water, from the aqueous feed (236). The extract is then dehydrated by azeotropic distillation using isoamyl acetate as water entrainer (see DISTILLATION, AZEOTROPIC AND EXTRACTIVE). It is claimed that the extraction step in this process affords substantial savings in plant capital investment and operating cost (see Acetic acid and derivatives). A detailed description of various extraction processes is available (237). 

Carboxylic acids having 6—24 carbon atoms are commonly known as fatty acids. Shorter-chain acids, such as formic, acetic, and propionic acid, are not classified as fatty acids and are produced synthetically from petroleum sources (see Acetic acid Formic acid and derivatives Oxo process). Fatty acids are produced primarily from natural fats and oils through a series of unit operations. Clay bleaching and acid washing are sometimes also included with the above operations in the manufacture of fatty acids for the removal of impurities prior to subsequent processing. 

Dichlorophenols. Among all the dichlorophenols, C H Cl O, it is 2,4-dichlorophenol that is produced in greatest quantity. 2,4-Dichlorophenol is used in manufacturing 2,4-dichlorophenoxyacetic acid [94-75-7] (2,4-D) and 2-(2,4-dichlorophenoxy)propionic acid [720-36-5] (2,4-DP). Industrially, 2,4-dichlorophenol can be obtained by chlorinating phenol, -chlorophenol, o-chlorophenol, or a mixture of these compounds in cast-iron reactors. The chlorinating agent may be chlorine or sulfuryl chloride in combination with a Lewis acid. For example ... 

Monsanto [117] has developed a way to electrosynthesize by reductive carboxylation the optically active precursor to Naproxen, (S)-2-(6 -methoxy-2 -naphthyl)propionic acid, a drug used to treat arthritis. A more economical route was needed since the US patent expires in 1993 while the market is growing. The electrochemical process is said to cut manufacturing costs by over 50%. Since it uses CO 2 instead of the hazardous HCN used in conventional synthesis, it is also safer. 

Lactose is readily fermented by lactic acid bacteria, especially Lactococcus spp. and Lactobacillus spp., to lactic acid, and by some species of yeast, e.g. Kluyveromyces spp., to ethanol (Figure 2.27). Lactic acid may be used as a food acidulant, as a component in the manufacture of plastics, or converted to ammonium lactate as a source of nitrogen for animal nutrition. It can be converted to propionic acid, which has many food applications, by Propionibacterium spp. Potable ethanol is being produced commercially from lactose in whey or UF permeate. The ethanol may also be used for industrial purposes or as a fuel but is probably not cost-competitive with ethanol produced by fermentation of sucrose or chemically. The ethanol may also be oxidized to acetic acid. The mother liquor remaining from the production of lactic acid or ethanol may be subjected to anaerobic digestion with the production of methane (CH4) for use as a fuel several such plants are in commercial use. 

The syntheses of carboxylic acids and esters are widely studied processes. Since the first examples of carboxylation in the presence of metal carbonyls were reported by Reppe, these reactions are sometimes referred to as the Reppe reactions. In his pioneering work125-127 stoichiometric or catalytic amounts of [Ni(CO)4] and ethylene or acetylene were reacted in the presence of water or alcohols to form saturated and unsaturated acids and esters. Commercial processes are practiced in the manufacture of propionic acid, acrylic acid and acrylates (see Section 7.2.4). 

S. thermophilus metabolizes lactose to l( +) lactic acid but utilizes only the glucose moiety of lactose, leaving the galactose moiety in the cheese (Tinson et al. 1982). In Swiss cheese manufacture, S. thermophilus metabolizes the lactose and L. helveticus metabolizes the galactose to d( —) and l( + ) lactic acid (Turner et al. 1983). The l( + ) lactate isomer is preferentially utilized by propionibacteria to form acetic and propionic acids, which are essential for the development of the characteristic flavor in Swiss cheese (Langsrud and Reinbold 1973). 

Cellulose esters of butyric and propionic acids have limited adhesive use. However, cellulose caprate, having a refractive index near that of glass and good resistance to photochemical change, is a useful hotmelt optical cement for the manufacture of compound lenses. 

The solubility restrictions that apply to the manufacture of the mixed esters are the same as those for the cellulose acetate, in that no soluble products are obtained by partial esterification. Hydrolysis of the esters in acid solution, however, yields uniform products showing gradually changing physical properties with increasing free hydroxyl content. The exact ratio of hydrolysis of acetyl to hydrolysis of propionyl or butyryl groups depends upon the composition of the hydrolysis solution. Thus, a cellulose acetate propionate hydrolyzed in acetic acid solution will retain a higher proportion of acetyl groups than would the same cellulose ester hydrolyzed in propionic acid. 

Solubihty soluble in water slightly soluble in ethanol (95%) and methanol practically insoluble in acetone and benzene. Method of manufacture prepared by the reaction of propionic acid and calcium hydroxide. 

Method of manufacture prepared by dissolving zinc oxide in dilute propionic acid solution. 

The sources of air pollutants include industrial as well as consumer use of chemicals. Virtually every one of man s activities in the twenty-first century results in the release of volatile and/or particulate matter xenobiotics into the air. Such activities include unexpected ones such as the opening of a loaf of bread (propionic acid is released from almost all packaged bread ) anc[ changing a baby s diaper (disposable diapers contain several volatile organic compounds introduced during their manufacture 2 ). 

Use Manufacture of propionic acid, polyvinyl, and other plastics synthesis of rubber chemicals disinfectant preservative. 

AI3-16114 Aldehyde propionique CCRIS 2917 EINECS 204-623-0 FEMA Number 2923 HSDB 1193 Methylacetaldehyde NCI-C61029 NSC 6493 Propaldehyde Propanal n-Propanal Propionai Propionaldehyde Propionic aldehyde Propyl aldehyde Propylic aldehyde UN1275. Used in the manufacture of propionic acid, polyvinyl and other plastics, synthesis of rubber chemicals, and preservatives. Liquid mp = -80 bp n 48 d = 0.8657 Am = 282 nm (e = 8, H2O) soluble in H2O, freely soluble in EtOH, Et20 LDsO (rat orl) = 1410 mg/kg. 

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