Decomposition of Bayer process organics: Phenolates, polyalcohols, and additional carboxylates

The degradation of nineteen low-molecular-weight phenolates, polyalcohols and selected aliphatic and aromatic carboxylates of relevance to the Bayer process has been studied in 6 mol kg-1 NaOH(aq) at 90 °C for up to 36 days, and (for some species) at 180 °C for up to 12 days, using HPLC and 13C NMR spectroscopy. Aliphatic polyalcohols degraded readily at 90 °C to lactate, oxalate, acetate, and formate. As observed previously, aliphatic carboxylates with hydroxyl groups also degraded readily at 90 °C but there is evidence that the position of the hydroxyl group may be important. The observed degradation products for most, but not all, of these species can be explained in terms of well-known organic reaction mechanisms. Phenolate and 5-hydroxyisophthalate were stable at 180 °C but other phenolic species degraded partially at 90 °C. However, the reaction products could not be identified and no trends in reactivity were discernible. Consistent with previous studies both aliphatic and aromatic carboxylates without hydroxyl groups were generally stable in NaOH(aq) even at 180 °C

Outcomes of a chemistry content professional learning session: Teachers' perspectives

The national curriculum for chemistry includes topics that have not previously been taught at secondary level. In response to requests for teacher professional learning (PL) covering these topics, a course called 'Divide and Analyse' was developed. Investigations into the PL needs of chemistry teachers were carried out in conjunction with the pilot session. Pre- and post-PL survey responses and focus group discussions provided a wealth of information about the needs of chemistry teachers and how university chemists can support them. Three themes of support for chemistry teaching were identified: resources for chemistry teaching, content PL for chemistry teachers and enrichment excursions/incursions for school students. Teachers explained that this type of support may contribute to making the study of chemistry more interesting and relevant for their students. A partnership between chemistry teachers and university chemists can facilitate the provision of the identified support for chemistry teaching. It was concluded that a community of practice partnership had developed from the Divide and Analyse PL. A model that brings together the major findings of the study is proposed

Using outreach, professional learning and research to build a co-operative learning community for chemistry education

Oral presentatio

What (WA) teachers want

Poster presentatio

Volatile products from the degradation of organics in a synthetic Bayer liquor

The formation of volatile substances such as hydrogen, methane, ketones, and aldehydes during alumina production using the Bayer process is of interest because of their process and occupational safety and health implications. To better understand how these substances are generated in the Bayer process, the decomposition of a selection of low-and high-molecular-weight organic materials has been studied at 180 C in a synthetic Bayer liquor consisting of 6 m NaOH. The main vapor-phase products were identified using gas chromatography with thermal conductivity or mass spectrometry detection. The results showed that caustic degradation of organic compounds commonly occurring in Bayer process liquors produces a range of substances known to be present in alumina refinery emissions. The main volatile products were H2, CH4, and certain carbonyl compounds with low odor thresholds, such as 2-butanone and propanone. There was also some evidence for the production of volatile pentacyclic compounds