In industry, propionic acid, an ethylene gidroksikarboksilirovaniem.
She also formed as a result of propionic brozheniya.Propionovaya acid is a byproduct of many processes, so you can use them to highlight it.
Propionic acid can be obtained in twoways: propionic acid fermentation and ethylene hydrocarboxylation. The second method is currently considered the most widespread in the industry. There are other known methods of producing less propionic acid, for example, separation of oil, catalytic oxidation of propionaldehyde selection as a byproduct in the vapor phase oxidation of hydrocarbons with a carbon number of 4-10.
For the first time to obtain the propionic acid by this method has implemented firm «BASF». It is characterized by high yield final product (about 95%), but have a number of disadvantages:
1) process required strict conditions: pressure reached 25-30 MPa, temperature - about 300 ° C.
2) the catalyst is highly corrosive and carcinogenic substances - nickel carbonyl and hydrogen iodide, respectively.
Later, on the basis of this method VNIINeftehimiireceipt has been finalized. The replacement of corrosive catalysts, cobalt-pyridine complex [Co (Py) 6] [Co (CO) 4] 2 became milder synthesis conditions percolation, which are now carried out in one step. The temperature was reduced to 150-170 ° C and the pressure - up to 5-15 MPa. The disadvantages of this method are:
1) A small reduction in the yield of the final product to 92%.
2) formation of by-product diethyl (5-7%). However, it has a separate application.
Equation propionic acid synthesis in one step: CH2 = CH2 + CO + H2O SN3SN2SOON?
propionic acid fermentation
Propionic acid fermentation is carried outpropionic acid by anaerobic bacteria of the genus Propionibacterium. Acid is produced as the end product of their life as a result of the absorption of carbohydrates. In the presence of oxygen digestion occurs because the oxidation process is carried out.
First, bacteria convert the carbohydrates in aa number of products, some of which are propionic acid. Here, it is not yet the final product. The resulting carbon dioxide is fixed and combines with pyruvic acid is converted into oxaloacetic, which is then converted to amber. Succinic acid is decarboxylated with the formation of propionic acid - the end product of fermentation. Shorten fermentation scheme can be written as follows:
3C6H12O6? 4CH3CH2COOH + 2CH3COOH + 2CO2? + 2H2O + E.