This paper explores measurement of product performance with respect to circular economy (CE) principles. Potential indicators are assessed with special attention given to questions such as: the variables that should be measured; how these variables should be assessed; and in which format they should be presented. The resulting considerations are used to develop a prototype whose design is informed through feedback from CE experts. The prototype uses a points-based questionnaire which converges into a simple final result with minimum and maximum limits. The selected approach is critically appraised, and its utility for decision-making discussed. The prototype is tested against a product in the chemical processing industry. The strengths include: ease of use; simplicity; speed; and an effective metaphor for the diffusion of CE principles. The limitations include: the opaque and potentially misleading nature of a single metric; superficial engagement with decision-making; and the reliance on context-specific assumptions. Future developments could include refining the approach to encourage deeper reflection, and generalisation of the approach to different industry sectors or sustainability frameworks.

The mechanism of the carbonylation of alkynes promoted by the Pd(OAc)2/2-pyridyldiphenylphosphine/methanesulfonic acid catalytic system has been studied. The carbonylation of 2-butyne in the presence of methanol affords stereospecifically the methyl ester of (E)-2-methyl-2-butenoic acid, indicating that the addition of H and COOCH3 moieties proceeds with cis stereochemistry. Experiments carried out using 1-alkynes and CH3OD reveal that the catalyst also promotes the exchange of the terminal hydrogen of the alkyne with the deuterium of the alcohol. 1H NMR experiments show that upon addition of phenylacetylene to a CD2Cl2 solution containing the catalyst and CH3OH a palladium complex having a 2-styryl group bound to the metal center, Pd−C(C6H5)CH2, is formed. This species can be invoked as an intermediate to account for both the H/D exchange and the carbonylation reaction. Carbonylation of 2-butyne in the presence of a 1/1 mixture of CH3OH and CH3OD indicates that a fairly large isotope effect (k H/k D = 6.4) is operative. All these results suggest that the carbonylation of alkynes proceeds via the protonation of a Pd(0)−alkyne species to give a Pd−vinyl complex, followed by CO insertion and alcoholysis.

Today, the scientific community is facing crucial challenges in delivering a healthier world for future generations. Among these, the quest for circular and sustainable approaches for plastic recycling is one of the most demanding for several reasons. Indeed, the massive use of plastic materials over the last century has generated large amounts of long-lasting waste, which, for much time, has not been object of adequate recovery and disposal politics. Most of this waste is generated by packaging materials. Nevertheless, in the last decade, a new trend imposed by environmental concerns brought this topic under the magnifying glass, as testified by the increasing number of related publications. Several methods have been proposed for the recycling of polymeric plastic materials based on chemical or mechanical methods. A panorama of the most promising studies related to the recycling of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and polystyrene (PS) is given within this review.

The coupling of arylboronic acids with electron‐rich allylic bromides is accomplished in the absence of any transition‐metal catalyst through conventional heating. The reaction is completely regioselective, affording only the α‐coupled product, and can be carried out under mild aerobic conditions in an organic solvent; the presence of a base is required.

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Abstract-The iminophosphine-palladium(0) complex [Pd(dmfu)(P-N)] [dmfu ¼ dimethyl fumarate; P-N ¼ 2-(PPh 2 )C 6 H 4 -1-CH@NC 6 H 4 -4-OMe] is a very efficient catalyst for the Suzuki coupling. In the reaction of aryl bromides with phenylboronic acid, turnover numbers up to ca. 200,000 are obtained at 110°C in 2 h. Good rates are obtained also with the sterically hindered and electronically deactivated 2-bromo-1,3,5-trimethylbenzene. The complex is able to catalyze the exhaustive arylation of 2, 3,7,8,12,13,17,10, to yield the corresponding undecaaryl substituted derivative.

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