LUIGI RIGANO*, CHIARA ANDOLFATTO
*Corresponding author
Rigano Industrial Consulting and Research, via Bruschetti 1, 20125, Milan, Italy

Abstract

Propylene glycol, also called 1,2-propane-diol, is a well-known multifunctional and versatile vicinal diol used in many industrial fields, in pharmaceuticals, foods and cosmetics. It has always been industrially prepared by the transformation of petroleum-derived stocks. Today, a new ‘green’ process allows to produce propylene glycol from corn starch in a special solvent-free, carbohydrate-to-glycols, process. This ‘green derived ‘propylene glycol is a high quality 1,2-propanediol made from corn. This means that it is derived from a 100% renewable source, without any mineral oil derived intermediates. This new process for producing a traditional synthetic ingredient meets the modern consumer’ requests, being fully equivalent to the propylene glycol produced from petroleum sources for all cosmetic applications, but it offers as additional advantage a more pleasant, fruity odour.

INTRODUCTION

Polyols are organic molecules containing more than one hydroxyl group in its structure, while glycols is the term designated for diols, that are compounds that contain only two hydroxyl groups situated in vicinal positions. Polyols occur naturally in plants and animals and are also produced synthetically (1). Both glycols and polyols have very important commercial value as precursor molecules to make polymers and for their own solvent and humectant properties.
Propylene glycol (PG), also known as 1,2-propane-diol, is an aliphatic di-alcohol that conforms to the formula in figure 1. PG contains one asymmetrical carbon atom, so that it exists in two optical isomers. The commercial product is a racemic mixture. PG is a clear, colourless, nearly odourless, from slightly bittersweet to tasteless, slightly viscous liquid, with low vapour pressure at room temperature (2).

For its special structure, the amphiphilic solvent power, the possibility to form extended hydrogen bonds associated with a good degree of compatibility with lipophilic molecules, it is a multifunctional and versatile polyol that is used in many industrial fields.< ...