PEG-5 isononanoate ester of nonanoic acid, a chemical compound primarily used in cosmetics and skincare products. 

The name describes the structure of the molecule:

• PEG-5 indicates the presence of polyethylene glycol (PEG) with an average molecular weight corresponding to 5 ethylene oxide units. PEG is known for its solubilizing and hydrating properties.
• Isononanoate refers to isononanoic acid, a fatty acid. Isononanoate in the context of this compound indicates that the PEG has been esterified with isononanoic acid.

Raw Materials and Their Functions

Polyethylene Glycol (PEG). A synthetic polymer used as the base for the formation of PEG-5 isononanoate. It is known for its solubilizing and hydrating properties.

Isononanoic Acid. A fatty acid used to esterify PEG, imparting emollient properties to the compound and improving its solubility in oils and fats.

Industrial Chemical Synthesis of PEG-5 Isononanoate

• Esterification. The process begins with the reaction of polyethylene glycol with isononanoic acid. During this reaction, ester bonds are formed between the PEG and the fatty acid.
• Reaction Control. The esterification reaction is monitored to ensure it occurs correctly and the desired product is formed.
• Purification. After the reaction, PEG-5 isononanoate is purified to remove impurities and by-products.
• Quality Control and Packaging. The purified PEG-5 isononanoate undergoes quality checks to ensure it meets the required standards. After quality control, it is packaged for use in cosmetic and personal care products, where it utilizes its properties as an emulsifier and conditioning agent.

Form and color

It appears as a colorless or very light liquid.

What it is used for and where

Cosmetics

Surfactant - Cleansing agent. Cosmetic products used to cleanse the skin utilise the surface-active action that produces a lowering of the surface tension of the stratum corneum, facilitating the removal of dirt and impurities. 

Surfactant - Emulsifying agent. Emulsions are thermodynamically unstable. Emulsifiers have the property to reduce the oil/water or water/oil interfacial tension, improve emulsion stability and also directly influence the stability, sensory properties and surface tension of sunscreens by modulating their filmometric performance.

PEGs

Since the PEG (Polyethylene glycol) family is very numerous and can be found in cosmetic, industrial, pharmaceutical, medical and other products, we need to make an introductory statement on the subject, which is rather complex from a safety point of view because these products not only come into contact with the skin, but, as in the case of medical products, are ingested.

PEGs (polyethylene glycol) polymerise condensed ethylene oxide and water and are referred to as polyethylene glycols, but are actually complex chemical components, polymers bonded together. For example, plastic is polyethylene and has a hard consistency, while polyethylene combined with glycol forms a liquid. PEGylation is produced not only as etherification, but also as transesterification, which is the transformation of an alcohol by an ester. 

The number appearing after the abbreviation PEG represents the molecular weight and the higher this number is, the less it penetrates the skin.

Safety

 The term 'eth' in Polyethylene Glycol (PEG) refers to the ethoxylation reaction with ethylene oxide after which residues of ethylene oxide and 1,4-dioxane, chemical compounds considered carcinogenic, may remain. The degree of safety therefore depends on the degree of purity of the compound obtained. At present, no manufacturer is known to provide this information on the label.