Itaconic acid has attracted considerable attention as a bio-based building block in radical polymerizations. However, only a few studies have been dedicated to polyesters derived from this interesting α,β-unsaturated dicarbonic acid. This review aims to highlight the most important work in this field and show the unique properties of these renewable unsaturated polyesters.

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We have developed a new benign means of reversibly breaking emulsions and latexes by using "switchable water", an aqueous solution of switchable ionic strength. The conventional surfactant sodium dodecyl sulfate (SDS) is not normally stimuli-responsive when CO2 is used as the stimulus but becomes CO2 -responsive or "switchable" in the presence of a switchable water additive. In particular, changes in the air/water surface tension and oil/water interfacial tension can be triggered by addition and removal of CO2 . A switchable water additive, N,N-dimethylethanolamine (DMEA), was found to be an effective and efficient additive for the reversible reduction of interfacial tension and can lower the tension of the dodecane/water interface in the presence of SDS surfactant to ultra-low values at very low additive concentrations. Switchable water was successfully used to reversibly break an emulsion containing SDS as surfactant, and dodecane as organic liquid. Also, the addition of CO2 and switchable water can result in aggregation of polystyrene (PS) latexes; the later removal of CO2 neutralizes the DMEA and decreases the ionic strength allowing for the aggregated PS latex to be redispersed and recovered in its original state.

Pipelining of heavy crudes can be facilitated by preparing oil-in-water (O/W) emulsions of the crude, but separation of the oil from the water after pipelining is problematic if conventional surfactants are used. Long-chain acetamidines are CO 2 -triggered switchable surfactants, being surface-active when CO 2 is present but not when CO 2 is absent. Unfortunately, in the presence of CO 2 , they stabilize water-in-oil (W/O) emulsions of heavy crude rather than the desired O/W emulsions. However, in the absence of added CO 2 , several compounds (Na 2 CO 3 , three of the long-chain acetamidines, and two other amidines) stabilize O/W emulsions. These low-viscosity emulsions can later be broken by the addition of CO 2 . The residual oil content in the recovered water is lowest if the compound used to stabilize the original emulsion was a long-chain acetamidine.

The practice of adding salt to water to induce salting out of contaminants or to break emulsions and suspensions is generally avoided industrially because of the expense of the necessary treatment of the salty water afterwards. However, the use of switchable water, an aqueous solvent with switchable ionic strength, allows for reversible generation and elimination of salts in aqueous solution, through the introduction and removal of CO 2 . In the effort to improve the efficiency of these switchable salts, a physical study modeling their reactivity and solution behaviour has been performed, resulting in a set of design principles for future switchable water additives. The resulting polyamines synthesized using this template show the highest efficiency recorded for a switchable water additive. † Electronic supplementary information (ESI) available: General procedures, experimental details, crystallography data. CCDC reference number 860228. For ESI and crystallographic data in CIF or other electronic format see

Dedicated to Professor Helmut Schwarz on the occasion of his 70th birthday deoxygenation · Lewis acids · pincer complexes · Si À H bond activation · silicon Scheme 4. Reduction of protected glucose derivatives 3 and 5 catalyzed by 1 (PG = EtMe 2 Si).Scheme 5. Exhaustive reduction of a persilylated glucose 5 (PG = EtMe 2 Si).

The renaissance of the bio-based chemical industry over the last 20 years has seen an ever growing interest in the synthesis of new bio-based polymers. The building blocks of these new polymers, so called platform molecules, contain significantly more chemical functionality than their petrochemical counterparts (such as ethene, propene and para-xylene). As a result bio-based polymers often contain greater residual chemical functionality in their chains, with groups such as alkenes and hydroxyls commonly observed. These functional groups can act as sites for post-polymerization modification (PPM), thus further extending the range of applications for bio-based polymers by tailoring the polymers' final properties. This mini-review highlights some of the most recent and compelling examples of how to make use of bio-based polymers with residual functional groups for PPM. It also looks at how the emerging interdisciplinary field of enzymatic polymer synthesis allows for increased functionality in polymers by avoiding side-reactions as a result of milder reaction conditions, and additionally offers an alternative means of polymer surface modification.

Challenges and opportunities for paints and coatings.