Ethoxylate/propoxylate ratio

Figure 11.7 is the H-NMR spectrum of an alkyl ethoxylate/propoxylate. This is made commercially by reaction of the appropriate fatty alcohol with a mixture of ethylene oxide (EO) and propylene oxide (PO). The level of incorporation of the EO/PO units greatly affects the polymer s surfactancy properties. This ratio, i.e. nim, can be determined by integration, as shown below. The integrals are not shown on this spectrum (for clarity), but they have been calibrated by using the terminal methyl of the alkyl chain (0.9 ppm) as internal standard. The peak assignments on the spectrum have been made using the principles outlined in section 11.5.3. 

Linear ethoxylates are tine preferred raw materials for production of ether sulfates used in detergent formulations because of uniformity, high purity, and biodegradahility, The alkyl chain is usually in the C y. to Cy range having a molar ethylene oxide alcohol ratio of anywhere from 1 1 to 7 1. Propoxylates, ethoxylates, and mixed alkoxylates of aliphatic alcohols or alkyl phenols are sulfated for use in specialty applications. 

One observes that with temperature increase, the ratio between the reaction rate of EO with the primary hydroxyl, as per the reaction rate of EO with secondary hydroxyl, decreases. If at 70 °C, EO is three times more reactive in the reaction with the primary hydroxyl than with the secondary hydroxyl at 120 °C, EO is only 1.6 times more reactive in the reaction with the primary hydroxyl than in the reaction with the secondary hydroxyl. As an immediate consequence, by ethoxylation of propoxylated polyethers at higher temperatures (125-130 °C), a more uniform distribution of EO units per hydroxyl group takes place and the resulting primary hydroxyl content is higher than that resulting from ethoxylation at lower temperatures (90-105 °C). Of course, another beneficial effect of a higher ethoxylation temperature is that the equilibrium of alcohol - alcoholate is established more rapidly. 

A special aromatic aminic polyol was obtained by propoxylation or ethoxylation of aniline [7]. These diols were used sometimes as chain extenders in elastomers and in coatings. The disadvantage of these aniline-based diols is the fact that at a ratio of 2 mols of alkylene oxide (PO, especially EO) they become solid at room temperature, by crystallisation ... 

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