Potassium t-butoxide-initiated elimination on substrate 1,1,2-trimethoxyethane

1-bromo-2,2-dimethoxyethane (I) was prepared in 68% yield from the addition of bromine to a solution of vinyl acetate and methanol. A Williamson ether synthesis, using sodium methoxide in methanol and I, gave 1,1,2-trimethoxyethane (II) in 48% yield. The compound (II) was the desired substrate for elimination reactions because it contains poor leaving alkoxide groups. Many different reactions were investigated to convert II into 1,2-dimethoxyethylene. Among these were pyrolysis, acid catalyzed eliminations, and base initiated elimination reactions. Best results were obtained using a bomb reactor, compound II as substrate, and potassium t-butoxide as the base. From this reaction, tertiary-butyl methyl ether, tertiary-butanol, cis-1,2-dimethoxyethylene and trans-1,2-dimethoxyethylene were isolated by preparative gas chromatography and identified as end products. A combination of elemental analysis, chemical tests, infrared spectroscopy, analytical gas chromatography, and nuclear magnetic resonance spectroscopy, prove conclusively and unambiguously the structures of the final products. An interesting analogy of the NMR spectra of cis-and-trans-1,2-dimethoxyethylene is made with the NMR spectra of cis-and-trans-1,2-difluoroethylene

The preparation of CIS- and trans-1,2-dimethoxyethylene. The study of the CIS-trans-rearrangement and evaluation of equilibrium constants

Equilibrium constants for the mercuric acetate-catalyzed reaction, cis-CH3 OCH=CHOCH3 D trans-CH3 OCH=CHOCH3, have been determined in the liquid and vapor phase over the temperature range 30° - 175°C by gas chromatography analysis. A novel synthesis of the cis- and trans-isomers of 1,2-dimethoxyethylene is discussed. From a screening of 29 catalysts, mercuric acetate, mercuric benzoate, and mercuric salicylate were found to be favorable isomerization catalysts. For the liquid phase reaction, ln K = -779.8/T + 0.6748 with ΔH° = +1.549 ± 0.019 Kcal/mole and ΔS° = +1.34 ± 0.05 e.u./mole Similarly, for the vapor phase reaction, ln K = -727.2/T + 0.8335 with ΔH° = +1.445 ± 0.054 Kcal/mole and ΔS° = +1.66 ± 0.15 e.u./mole A linear regression analysis, employing a least-squares curve fit and an analysis of variance, was performed on the data. An independent experimental error analysis (for uncertainties in measurement, reproducibility, etc.) was performed using partial differentials and was consistent with the above findings. cis-1,2-Dimethoxyethylene was more stable relative to its trans-isomer in both the liquid and vapor phase. The greater amount of cis-isomer present at equilibrium (the cis-effect) is discussed in terms of dipole-dipole interactions with a resultant increase in the C=C bond strength for the cis-isomer due to electron density shifts. The dimethoxyethylenes are correlated with previous results found in the literature for related systems (e.g. dihaloethylenes, etc.). Additional arguments are also advanced

Characterization of Chlorinated Ethene Degradation in a Vertical Flow Constructed Wetland

Chlorinated solvents, including perchloroethene (PCE) and trichlorethene (TCE), are among the most common groundwater contaminants found in the United States. Once released into the environment, chlorinated solvents are extremely persistent and often require costly and lengthy remedial actions. The use of constructed wetlands has shown promise as an effective and less costly alternative for the treatment of chlorinated solvent contaminated groundwater. This study characterized and evaluated the concentration of chlorinated ethenes within a vertical flow constructed wetland, fed with PCE contaminated groundwater, at Wright-Patterson Air Force Base (WPAFB), Ohio. Chlorinated ethene concentrations were characterized within three distinct layers of the wetland cell, as well as within the influent, and effluent. In addition, a pore-water sampler prototype was designed and developed for this research effort in order to obtain a more detailed contaminant profile. PCE concentrations declined from an average of 46.5 μg/L in the influent to an average of 0.5 μg/L in the upper layer, a 98.9% decrease. The chlorinated ethene concentration profiles indicate that the lower half of the wetland provides favorable conditions for the complete anaerobic reductive dechlorination of the PCE. Within the upper half of the wetland, contaminant profiles indicate dominant degradation processes other than anaerobic reductive dechlorination, possibly including aerobic or anaerobic oxidation or direct volatization. The limited data generated from the implementation of the pore-water sampler prototypes was inclusive, requiring the need for further testing and research

Drug Use in Young Adults Engaging with the Nightlife Scene: A Longitudinal European Survey

The use of alcohol and illicit drugs has long been a feature in the nightlife scene. However, there is a current paucity of research on contemporary patterns of drug use in European nightlife populations. Furthermore, there have been considerable developments in the European drug market, potentially placing people at elevated risk of harm. In Chapter 1, I provide an overview of this key gap in the literature and introduce the ALAMA-Nightlife project, a multi-country collaboration designed to address this. In Chapter 2, I demonstrate that the internet can be successfully used to recruit a sample of young European adults engaging with the nightlife scene, by showing an online sample to be broadly representative in terms of drug use, nightlife engagement and demographics as an offline sample recruited at nightclubs and festivals. The cross-sectional profiles of drug use are examined in Chapter 3, with Latent Class Analysis revealing six distinct subgroups indicating substantial heterogeneity in drug use patterns. Furthermore, increasing levels of polydrug use were associated with higher scores on indices of problematic alcohol and drug use. In Chapter 4, I examined the relationship between harm reduction and polydrug use, and identified five discrete patterns of personal protective strategies that differed in levels of polydrug use. Extensive endorsement of harm reduction behaviours was also associated with more positive and fewer negative consequences following drug use. Longitudinal trajectories of drug use in the European nightlife scene are assessed in Chapter 5, with findings suggesting considerable stability over the course of 12 months. Amongst the small percentage whose use did change at follow-up, both an increase and decrease were associated with lower perceptions of risk, while increasing or decreasing the number of electronic dance music events attended was associated with a corresponding change in drug use. In Chapter 6, I summarise these findings, discuss their implications and how they address current gaps in the evidence while considering their limitations, and suggest areas for future research on drug use in the European nightlife scene

Skew Hecke Algebras

Let $G$ be a finite group, $H \le G$ a subgroup, $R$ a commutative ring, $A$ an $R$-algebra, and $\alpha$ an action of $G$ on $A$ by $R$-algebra automorphisms. Following Baker, we associate to this data the \emph{skew Hecke algebra} $\mathcal{H}_{R}(G,H,A,\alpha)$, which is the convolution algebra of $H$-invariant functions from $G/H$ to $A$. In this paper we study the basic structure of these algebras, proving for skew Hecke algebras a number of common generalisations of results about skew group algebras and results about Hecke algebras of finite groups. We show that skew Hecke algebras admit a certain double coset decomposition. We construct an isomorphism from $\mathcal{H}_{R}(G,H,A,\alpha)$ to the algebra of $G$-invariants in the tensor product $A \otimes \mathrm{End}_{R} ( \mathrm{Ind}_{H}^{G} R )$. We show that if $|G|$ is a unit in $A$, then $\mathcal{H}_{R}(G,H,A,\alpha)$ is isomorphic to a corner ring inside the skew group algebra $A \rtimes G$. Alongside our main results, we show that the construction of skew Hecke algebras is compatible with certain group-theoretic operations, restriction and extension of scalars, certain cocycle perturbations of the action, gradings and filtrations, and the formation of opposite algebras. The main results are illustrated in the case where $G = S_3$, $H = S_2$, and $\alpha$ is the natural permutation action of $S_3$ on the polynomial algebra $R[x_1,x_2,x_3]$.Comment: 35 page