Propylene glycol Production

Bis(2-chloro-l-methylethyl)ether has been produced as a solvent and soil fumigant and is also formed in large quantities as a by-product in some propylene oxide/propylene glycol production processes. Low levels have been found in water. Thus, both occupational and environmental exposures may occur (lARC, 1986). 

Propylene glycol production Maximization of economic benefit and minimization of environmental indicator. In addition process robustness measures (deviation ratio) were also considered. Normal boundary intersection method Sustainable process index was used as environmental indicator. Product revenue less capital and operating costs was the economic indicator Kheawhom and Hirao (2002)... 

Mg. 7.7. Propylene glycol production by propylene oxide hydralion. 

EXPOSURE ROUTES waste streams from propylene glycol production consumption of contaminated drinking water occupational settings inhalation of vapors eye and skin contact... 

Pump the contents of the still pot into the propylene glycol product receiver. 

As can be seen, the total batch time is nearly 8 hr, the amounts of 99.9 mol% methanol and 99.98 mol% propylene glycol products are 29.88 Ibmol and 33.03 Ibmol, respectively. Note that after step 4 the methanol product accumulator contains 0.999 X 29.88 = 29.85 Ibmol methanol. The remainder, 33.33 - 29.85 = 3.48 Ibmol methanol is recovered initially in the water product accumulator during step 6. Hence, the water product accumulator contains a slop cut of water. Nearly all of the propylene glycol is recovered in the still. These results can be reproduced using the BATCHHiAC file, EXAM 12-3. bkp, on the multimedia CD-ROM. ... 

Water is supplied in large excess in order to favour propylene glycol production. The reaction is catalysed by sulfuric acid and takes place at room temperature. In order to dilute the feed and to keep the propylene oxide soluble in water, methanol is also added. The reaction is carried out in a 5-litre stirred-jacketed glass reactor. Initial conditions described by Furusawa et al. (1969) have been applied an equivolumic feed mixture of propylene oxide and methanol is added to the reactor initially supplied by water and sulfuric acid, for a propylene oxide concentration of 2,15 mol/L. In agreement with previous works reported in literature, kinetic parameters of the reaction modelled by an Arrhenius law are summarised in table 1. 

The determination of the optimal reflux profiles leads to equivalent results in the case of propylene glycol production with or without by-products constraint. In fact, due to a reaction step carried out with large water excess, the compositions at the beginning of the separation step are quite identical, independently of the considered production. 

Pretend you are a low achieving student Write a chemical reaction for propylene glycol production based on the figure above. 

Xiao, J., Huo, Z., Ren, D., et al., 2015. A novel approach for 1,2-propylene glycol production from biomass-derived lactic add. Process Biochemistry 50 (5), 793-798. 

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