Search

Allylic alcohols such as geraniol and nerol undergo epoxidation with peroxy acids in aqueous medium and produce the corresponding epoxides in high yield. The introduction of the surfactant cetyltrimethylammonium hydroxide increases the afforded yields in reactions involving magnesium monoperoxyphthalate and monoperoxyphthalic acid. The efficiency of the surfactant relies on the interaction of epoxidation reactivity, alcohol solubility and reactant orientation. Additionally, the regulation of the medium's pH determines the regioselectivity of the reaction.

A new technology was tested to improve the cooking efficiency of the raw mixture for Portland clinker production by the use of nano-Ca(OH) 2 . A decrease in the free lime concentration after the firing of approximately 35% and 55% in the nano-added clinkers burned at 1350 °C and 1450 °C, respectively, with respect to the standard Portland clinkers was observed. Moreover, in the nano-added clinkers, a slight decrease in alite (C3S), of approximately 2-4 wt%, and increase in belite (C2S), of approximately 5-6 wt%, were observed. Despite these variations, the C2S and C3S abundance lies within the ranges for standard Portland clinkers. The results showed that the nano-addition leads to an increase of the raw mixtures' cooking efficiency. The relatively low energy required for the clinker firing could be used to increase the plant productivity and decrease the CO 2 emissions during clinker burning. The decrease of the work index of the clinkers produced by the use of the nano-Ca(OH) 2 also contributes to the energy saving during clinker grinding. Differences were also found in the pore size distribution among nano-added clinkers and the standard Portland clinker. The smallest porosities with the modal volume lying in the class of 3∙10 -6 mm 3 were found to increase by the use of nano-Ca(OH) 2 . However, the pore volumes higher than 2.0∙10 -5 mm 3 decreased in the nano-added clinkers., Competing Interests: The authors declare no conflict of interest.