Pentacrythritol Manufacturing

The formula or Pentacrythritol is C(CH2OH)4, with molecular weight 136.14. Pentacrythritol is a white or light yellow with a little sweetness and soluble in water and ethanol, insoluble in benzene, ethyl ether and other mineral ether. Pentacrythritol have boiling point 276 oC and melted in 262 oC, have density of 1.35 g/cm3 and have refractive index 1.54 – 1.56.

Pentacrythritol is mainly used in the production of alkyd resin and as material of paint industry, besides as explosive material, floor paint and air lubricant oil. To handling this material should be placed in a dry clean and ventilated place, should avoid heating, damp and direct contacting to sunshine.

How to produce this material still being patented by Harry Jackson, William M. Kraft et al, and other scientist. Some journal just describe the main reaction of the manufacturing of this substances. The invention relates to a process for resolving into its component materials the waste liquor resultant from the manufacturing of pentacrythritol. More particularly, the invention relates to a process for the recovery of pentacrythritol, polypentacrythritols and formic acid salts from such waste liquor.

Pentacrythritol is conventionally produced by the condensation of acetaldehyde with formaldehyde in a aqueous medium containing a condensation catalyst. Alkali metal and alkaline earth metal compounds which are alkaline reacting in aqueous solution are normally used as condensation catalyst. Thus the oxydes, hydroxide and calcium hydroxide are particularly favored commercially as condensation catalysts for manufacture. The main reaction taking place in a system of this type are believed to be like this:

3HCHO + CH3CHO ----> (HOCH2)3-CCHOCHOCH2)3CCHO + HCHO + NaOH ----> (HOCH2)4C + NaCOOH

Regardless of the theory, a metal formate corresponding to the metal ion of the condensation catalyst is always found in considerable quantity in the reaction mixture. At the end of the condensation period, technical pentacrythritol is usually recovered from the reaction mixture by fractional crystallization. Several successive crops of pentacrythritol crystals can be removed from the reaction mixture in this manner. The result from the fractional crystallization a mother liquor or waste liquor, which is not practically to attempt further recovery or pentacrythritol by fractional crystallization, due to largely to the difficultly of inducting crystallization in such waste liquor and the excessive contamination of any products so obtained with metal formate, syrups, etc.

In the manufacturing process of pentacrythritol monomer formed, there are formed comparatively small amounts related hydroxylated substances. One of these compounds, dipentacrythritol, is an ether.

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