<p>The study examined the potential of the Ru/MgO catalyst for the ring-opening of ethylene oxide (EO) and its application in the synthesis of ethoxylated products.&#xa0;This is the first time that Ru/MgO catalyst has been applied to the ring-opening reaction of ethylene oxide for the synthesis of narrow-distribution fatty alcohol ethers, providing a new catalytic solution for this field.&#xa0;During the ethoxylation reaction, although the induction period of Ru/MgO catalyst is relatively longer than that of potassium hydroxide and magnesium/aluminum catalysts, its small usage leads to the highest catalytic efficiency and does not have any adverse effects on the content of dioxane and polyethylene glycols (PEG) in the final product. The results of gas phase distribution determination of component composition indicate that the catalyst has a significant narrow distribution effect.&#xa0;The content of unreacted alcohols in fatty alcohol polyoxyethylene ether (AEO) is only 7.64% (AEO3-3), which is 57% lower than the 17.66% in traditional potassium hydroxide. The composition content of the target product 3EO has increased from 14.78% to 27.13%, an increase of 83.5%.&#xa0;The optimal number of cycles for the Ru/MgO catalyst is 5. After use, the product does not contain metal ions, and the catalyst does not require refined filtration and separation.&#xa0;The Ru/MgO catalyst can not only synthesize AEO3 (atty alcohol polyoxyethylene ether with 3EO) with lower moles of ethylene oxide, but also synthesize higher molecular weight AEO7 (atty alcohol polyoxyethylene ether with 7EO) and AEO9 (atty alcohol polyoxyethylene ether with 9EO), demonstrating its potential for industrial applications in enhancing product diversity and meeting different industrial needs.</p> Graphical Abstract <p></p>