Parameters propylene glycol production

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. 

Lehtonen et al. (1998) considered polyesterification of maleic acid with propylene glycol in an experimental batch reactive distillation system. There were two side reactions in addition to the main esterification reaction. The equipment consists of a 4000 ml batch reactor with a one theoretical plate distillation column and a condenser. The reactions took place in the liquid phase of the reactor. By removing the water by distillation, the reaction equilibrium was shifted to the production of more esters. The reaction temperatures were 150-190° C and the catalyst concentrations were varied between 0.01 and 0.1 mol%. The kinetic and mass transfer parameters were estimated via the experiments. These were then used to develop a full-scale dynamic process model for the system. 

Table 1 list solvents and cosolvents used in parenteral products. Water for injection is the most common solvent but may be combined or substituted with a cosolvent to improve the solubility or stability of drugs.f The dielectric constant and solubility parameters are among the most common polarity indices used for solvent blending.f Ethanol and propylene glycol are used either alone or in combination with other... 

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