Reactivities of organic poly-halogen compounds

Two recent investigations have shown that an x-chlorine substituent increases S(_N)1 reactivity, but analysis of the trends in E(_A) and (_Δ)S* values in each case, shows that serious discrepancies exist between them. In view of this it was considered that the role of an x-chlorine substituent was still uncertain and it was decided to look into the matter further. Towards this end, the solvolyses of benzyl chloride, benzal chloride, benzotrichloride, diphenylmethyl chloride and diphenylmethylene chloride have been examined in various solvents, over as wide a range of temperatures as possible, consistent with accurate results, it being considered that the mechanism of solvolysis was S(_N)1 in all cases, with the possible exception of benzyl chloride. Analysis of the E(_A) and ΔS* values for the solvolyses of these compounds shows, in the first place, that the sol volysis of benzyl chloride is not straight forward S(_N)1. Its mechanism of solvolysis is discussed in chapter VII where it is concluded that it proceeds by a single, predominantly S(_N)2 mechanism. Further analysis of the E(_A) and ΔS* values (and in some cases AC*(_p) values) of the other compounds, in chapter VI, indicates that the primary role of an x-chlorine substituent in S(_N)1 reactions is electron release, although, as a second order effect it appears to cause an increase in the extent of solvation of the transition state. The disturbing effects in the hydrolysis of diphenyl methylene chloride in aqueous acetone are analysed in part II where it is shown that they can be quantitatively explained, over a wide range of experimental conditions, on the basis of the mass law and ionic strength effects, proposed by Hughes and Ingold, in S(_N)1 reactions. The exceptionally large mass law effect for diphenyl methylene chloride is ascribed to powerful electron release by the x-chlorine atom, so confirming the conclusions reached in part I

Separation and Artificial Maturation of Macerals from Type II Kerogen

Immature Type II kerogen (HI= 660 mg/g) from the Lower Toarcian of the Paris Basin was separated into an alginite concentrate (HI = 952 mg/g) and an amorphous organic matter (AOM) concentrate (HI = 573 mg/g) by density centrifugation. The flash pyrolyzate of the alginite is characterized by high relative concentrations of several series of n-alkanones and n-alkenones (including mid-chain alkyl ketones), in addition to n-alkanes, n-alk-1-enes and n-alkadienes. To our knowledge, this Toarcian alginite is the oldest example of marine organic matter whose pyrolyzate contains mid-chain alkanones in such high relative concentrations. In sharp contrast, the AOM produced predominantly alkylbenzenes, alkylthiophenes, n-alkanes and n-alk-1-enes upon pyrolysis. Micro-FTIR spectroscopy indicated that the alginite was enriched in aliphatic C-H (particularly CH2) and depleted in aromatic C=C, relative to the AOM, consistent with the pyrolysis results. Aliquots of the concentrates were heated separately in gold tubes (24 h, 70 MPa) at fixed temperatures ranging between 250 and 375°C. Yields of liquid products as a function of temperature were initially greater for the AOM, reaching a maximum at 325°C. In contrast, the alginite yielded little liquid product at low temperatures, attaining its maximum at 350°C, at which temperature its yield greatly surpassed that of the AOM. This kerogen is a heterogeneous assemblage of fossil organic matter, exhibiting different degrees of preservation and petroleum potential. The alginite is fossilized marine algaenans with alkyl chains cross-linked by ether bridges, while the AOM component is at least in part a geopolymer with thioether linkages, the thermally labile nature of which is responsible for its lower temperature peak liquid generation. It is evident that the alginite concentrate is chemically distinct from its companion AOM in this kerogen and that the full extent of its uniqueness would not have been revealed without the density separation step

Helping education undergraduates to use appropriate criteria for evaluating accounts of motivation

The aim of the study was to compare students in a control group with those in a treatment group with respect to evaluative comments on psychological accounts of motivation. The treatment group systematically scrutinized the nature and interpretation of evidence that supported different accounts, and the assumptions, logic, coherence and clarity of accounts. Content analysis of 74 scripts (using three categories) showed that the control group students made more assertions than either evidential or evaluative points, whereas the treatment group used evaluative statements as often as they used assertion. The findings provide support for privileging activities that develop understanding of how knowledge might be contested, and suggest a need for further research on pedagogies to serve this end. The idea is considered that such understanding has a pivotal role in the development of critical thinking

Violent video games and morality: a meta-ethical approach

This paper considers what it is about violent video games that leads one reasonably minded person to declare "That is immoral" while another denies it. Three interpretations of video game content a re discussed: reductionist, narrow, and broad. It is argued that a broad interpretation is required for a moral objection to be justified. It is further argued that understanding the meaning of moral utterances – like "x is immoral" – is important to an understanding of why there is a lack of moral consensus when it comes to the content of violent video games. Constructive ecumenical expressivism is presented as a means of explaining what it is that we are doing when we make moral pronouncements and why, when it comes to video game content, differing moral attitudes abound. Constructive ecumenical expressivism is also presented as a means of illuminating what would be required for moral consensus to be achieved

Personal values and involvement in problem behaviors among Bahamian early adolescents: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Few studies, particularly in developing countries, have explored the relationship between adolescents and parental values with adolescent problem behaviors. The objectives of the study are to (1) describe adolescents' personal values, their problem behaviors, and the relationships thereof according to gender and (2) examine the relationship between parental values, adolescent values, and adolescents' problem behaviors among sixth-grade students and one of their parents.</p> <p>Methods</p> <p>The data used in these analyses were from the baseline assessment of a school-based HIV risk reduction intervention being conducted and evaluated among sixth grade students and one of their parents across 9 elementary schools in The Bahamas. Personal values were measured by the Portrait Values Questionnaire (PVQ). Seven reported problem behaviors were queried from the students, which included physical fight with a friend, drank alcohol, beer, or wine, smoked a cigarette, pushed or carried any drugs, carried a gun, knife, screwdriver or cutlass to use as a weapon, had sex and used marijuana or other illicit drugs over the past 6 months. Multilevel modeling for binary data was performed to estimate the associations between adolescent and parental values and adolescent problem behaviors.</p> <p>Results</p> <p>Among 785 students, 47% of the students reported at least one problem behavior. More boys (54%) reported having one or more problem behaviors than girls (41%, p < 0.01). Boys compared to girls expressed a higher level of self-enhancement (means score: 36.5 vs. 35.1; p = 0.03), while girls expressed a higher level of self-transcendence (42.3 vs. 40.7; p = 0.03). The results of multilevel modeling indicates that boys with a higher level of self-enhancement and girls with a higher level of openness to change and a lower level of conservation were more likely to report engagement in problem behaviors. Only two parental values (self-transcendence and conservation) were low or modestly correlated with youth' values (openness to change and self-enhancement). Parental-reported values documented limited association on adolescents' reported values and behaviors.</p> <p>Conclusion</p> <p>In designing interventions for reducing adolescents' problem behaviors, it may be important to understand the values associated with specific problem behaviors. Further exploration regarding lack of association between adolescent and parental values and problem behaviors is needed.</p

Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study

A41 Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study In: Addiction Science & Clinical Practice 2017, 12(Suppl 1): A4