Narrow-range ethoxylates (NREs) in chemistry are fatty alcohol

polyglycol ether Glycol ethers are a class of chemical compounds consisting of alkyl ethers that are based on glycols such as ethylene glycol or propylene glycol. They are commonly used as solvents in paints and cleaners. They have good solvent properties while h ...

s with a narrow homolog

distribution Distribution may refer to: Mathematics * Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations *Probability distribution, the probability of a particular value or value range of a vari ...

and are known nonionic surfactants. They can be produced industrially, for example, by the addition of

ethylene oxide Ethylene oxide is an organic compound with the formula . It is a cyclic ether and the simplest epoxide: a three-membered ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless and flammable gas with a faintly sw ...

onto fatty alcohols in the presence of suitable

catalyst Catalysis () is the process of increasing the reaction rate, rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the ...

s (layer compounds which have been calcined or hydrophobized with fatty acids).Reviews on this subject are presented, for example, by M. Cox in '' J. Am. Oil Chem. Soc.'' 67, 599 (1990) and by H. Hensen et al. in Seifen-Ole-Fette-Wachse, 117, 592 (1991). This process can also be carried out on a variety of other hydrophobes and using different alkoxylating compounds (e.g., propylene oxide and

butylene oxide Epoxybutane may refer to: * 1,2-Epoxybutane * 1,4-Epoxybutane (tetrahydrofuran) * 2,3-Epoxybutane 2,3-Epoxybutane is an organic compound with the formula CH3CH(O)CHCH3. It is an epoxide. The compound exists as three stereoisomers, a pair of en ...

) by modifying the catalyst properties.

Example

An ethoxylation reaction proceeds under an inert atmosphere with an amount of heat depending on the starting material. The reaction proceeds via the epoxide (in this case

) ring opening and activation of the nucleophile, ring, or combination thereof via the catalyst. With conventional catalysts (i.e. potassium hydroxide, sodium hydroxide, etc.) one obtains a distribution of ethoxymers. If one targets a 12

mole Mole (or Molé) may refer to: Animals * Mole (animal) or "true mole", mammals in the family Talpidae, found in Eurasia and North America * Golden moles, southern African mammals in the family Chrysochloridae, similar to but unrelated to Talpida ...

ethoxylate with a conventional

alkaline earth The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).. The elements have very similar properties: they are all ...

hydroxide, one could expect to get a broad range of ethoxylates with n being anywhere from 3 to 30 moles of EO. With narrow-range catalysts a much tighter distribution can be obtained. Narrow-range surfactants like alcohol ethoxylates and propoxylates can be incorporated into alkyl ether sulfates or mixed with other anionic surfactants and exhibit beneficial properties such as reduced irritation to skin/eyes and lower free alcohol content.

References

{{Reflist Ethers Non-ionic surfactants