A stereospecific one-pot synthesis of β-chloro esters via the BiCl<inf>3</inf> catalysed O-acylative cleavage of crowded epoxides

© 2015, Science Reviews 2000 Ltd. All rights reserved. A simple, one-pot procedure is described for the stereospecific preparation of β-chloro esters from the corresponding crowded epoxide

The development of novel fuel dehydrating icing inhibitors

Dissolved water is a normal component of jet fuel which is vapourised during combustion; however, free water is a contaminant that can starve engines, freeze to form ice crystals capable of blocking fuel feeds, support microbial growth, and contribute towards corrosion. Jet fuel may be protected from the potentially hazardous effects of free-water using biocides and corrosion/icing inhibitors. This investigation seeks to identify novel chemical approaches to the dual management of water contamination and ice formation in jet fuel. The strategy of using organic molecules as dehydrating agents remains a relatively neglected solution, perhaps because of the complexity of the physical organic chemistry involved in developing and refining these systems. This Thesis describes our systematic approach towards the development of jet fuel additives which are kinetically fast, selective, lipophilic water scavengers that produce, upon hydrolysis, a hydrophilic ice inhibitor [Fuel Dehydrating Icing Inhibitors (FDII)]. A qualitative and quantitative analysis of the factors influencing the rates of hydrolysis for carefully selected geminal ethers is presented. The mechanistic understanding of the hydrolysis reactions of five and six membered geminal ethers has been consolidated using a combined kinetic 1H NMR, isotopic labelling and computer assisted conformational analyses approach. For the first time, stereoelectronic arguments have been employed to rationalise the rates of hydrolysis of five membered ortho esters. A novel one-pot stereospecific O-acylative cleavage of epoxides is presented. It is anticipated that this new synthetic methodology would provide access to novel FDII in the future. Finally, logKOW calculations have been used to predict the partitioning behaviour of FDII, and thereby screen candidate molecules for future study. We believe that FDII represents a novel and versatile approach for protecting jet fuel against the effects of water contamination

The hydrolysis of geminal ethers: A kinetic appraisal of orthoesters and ketals

© 2016 Repetto et al. A novel approach to protecting jet fuel against the effects of water contamination is predicated upon the coupling of the rapid hydrolysis reactions of lipophilic cyclic geminal ethers, with the concomitant production of a hydrophilic acyclic hydroxyester with de-icing properties (Fuel Dehydrating Icing Inhibitors - FDII). To this end, a kinetic appraisal of the hydrolysis reactions of representative geminal ethers was undertaken using a convenient surrogate for the fuel-water interface (D2 O/CD3 CN 1:4). We present here a library of acyclic and five/six-membered cyclic geminal ethers arranged according to their hydroxonium catalytic coefficients for hydrolysis, providing for the first time a framework for the development of FDII. A combination of 1H NMR, labelling and computational studies was used to assess the effects that may govern the observed relative rates of hydrolyses

Dual Action Additives for Jet A-1: Fuel Dehydrating Icing Inhibitors

© 2016 American Chemical Society. A novel approach for protecting jet fuel against the effects of water contamination based upon Fuel Dehydrating Icing Inhibitors (FDII) is presented. This dual-action strategy is predicated on the addition of a fuel-soluble water scavenger that undergoes a kinetically fast hydrolysis reaction with free water to produce a hydrophilic ice inhibitor, thereby further militating against the effects of water crystallization. Criteria for an optimum FDII were identified and then used to screen a range of potential water-scavenging agents, which led to a closer examination of systems based upon exo/endo-cyclic ketals and both endo- and exo-cyclic ortho esters. The ice inhibition properties of the subsequent products of the hydrolysis reaction in Jet A-1 were screened by differential scanning calorimetry. The hydrolysis products of 2-methoxy-2-methyl-1,3-dioxolane demonstrate similar ice inhibition performance to DiEGME over a range of blend levels. The calorific values for the products of hydrolysis were also investigated, and it is clear that there would be a significant fuel saving on use of the additive over current fuel system icing inhibitors. Finally, three promising candidates, 2-methoxy-2-methyl-1,3-dioxolane, 2-methoxy-2-methyl-1,3-dioxane, and 2-methoxy-2,4,5-trimethyl-1,3-dioxolane, were shown to effectively dehydrate Jet A-1 at room temperature over a 2 h period

A Meaningful U.S. Cap-and-Trade System to Address Climate Change

There is growing impetus for a domestic U.S. climate policy that can provide meaningful reductions in emissions of CO2 and other greenhouse gases. In this article, I propose and analyze a scientifically sound, economically rational, and politically feasible approach for the United States to reduce its contributions to the increase in atmospheric concentrations of greenhouse gases. The proposal features an up-stream, economy-wide CO2 cap-and-trade system which implements a gradual trajectory of emissions reductions over time, and includes mechanisms to reduce cost uncertainty. I compare the proposed system with frequently discussed alternatives. In addition, I describe common objections to a cap-and-trade approach to the problem, and provide responses to these objections

Equity and justice in global warming policy

Many countries are implementing or at least considering policies to counter increasingly certain negative impacts from climate change. An increasing amount of research has been devoted to the analysis of the costs of climate change and its mitigation, as well as to the design of policies, such as the international Kyoto Protocol, post-Kyoto negotiations, regional initiatives, and unilateral actions. Although most studies on climate change policies in economics have considered efficiency aspects, there is a growing literature on equity and justice. Climate change policy has important dimensions of distributive justice, both within and across generations, but in this paper we survey only studies on the intragenerational aspect, i.e.., within a generation. We cover several domains including the international, regional, national, sectoral and inter-personal, and examine aspects such as the distribution of burdens from climate change, climate change policy negotiations in general, implementation of climate agreements using tradable emission permits, and the uncertainty of alternatives to emission reductions

Behaviour of water in jet fuel: a literature review

This review gives a detailed account of the different types of water contaminated fuel and the conditions that bring about each form of contamination. It also considers studies that have been done to date that investigate the physics behind the behaviour of water in different hydrocarbons and jet fuel at low temperatures

The Development of Novel Fuel Dehydrating Icing Inhibitors

Dissolved water is a normal component of jet fuel which is vapourised during combustion; however, free water is a contaminant that can starve engines, freeze to form ice crystals capable of blocking fuel feeds, support microbial growth, and contribute towards corrosion. Jet fuel may be protected from the potentially hazardous effects of free-water using biocides and icing/corrosion inhibitors. This investigation seeks to identify novel chemical approaches to the dual management of both water contamination and ice formation in jet fuel. The strategy of using organic molecules as dehydrating agents remains a relatively neglected approach perhaps because of the complexity of the physical organic chemistry involved in developing and refining these systems. However, organic molecules with well characterised dehydrating properties - such as ortho esters, acetals, hemiacetals, ketals, and hemiketals - present themselves as an excellent starting-point for the development and optimisation of novel Fuel Dehydrating Icing Inhibitors (FDII). This paper describes our systematic approach towards the development of jet fuel additives which are kinetically fast, selective, lipophilic water scavengers that produce, upon hydrolysis, a hydrophilic ice inhibitor. A brief human and environmental toxicological screening of candidates is described. We anticipate that this class of FDII represents a novel approach towards protecting jet fuel against the effects of water contamination. Copyright © 2013 SAE International