Alessandro Rosengart

Process industry renovation is mostly driven by business objectives like productivity enhancement and cost reduction, which hinder the “shift towards a sustainable manufacturing” called by political and academic institutions. In this paper, the project management methodology of Value Engineering, used for cost reduction in large capital projects, is extended to improve not only economic figures, but also environmental sustainability indicators. The methods can guide project design to reduce the consumption of natural resources and the generation of waste, closing a gap between sustainability targets and production needs. Sustainability metrics derived from a simplified life cycle assessment approach are used to achieve quick but reliable estimates of the environmental impact reductions against a base scenario. The project governance is thus supported when assessing potential trade-offs between environmental and economic advantage, encouraging shared and de-risked decisions. Even though limited by the project boundaries of time and budget and by the simplified impact assessment approach, the method promotes a lean and incremental implementation of sustainable manufacturing practices, applicable also to routinary interventions. The methodology is illustrated through application examples from a real case study, an EUR 100 M chemical plant expansion project for a pharmaceutical company in Italy.

The hydrogenation of trans,trans-muconic acid was investigated on a Pt/C 5% (wt) catalyst in a batch slurry reactor at constant hydrogen pressure (4 bar) and temperature (323, 333 and 343 K), with the purpose of developing a kinetic model able to predict conversions and product distributions. A dual-site Langmuir–Hinshelwood–Hougen–Watson (LHHW) model with hydrogen dissociation provided good fitting of the experimental data. The model parameters were regressed by robust numerical methods to overcome the computational challenges of the model parameters’ collinearity. Different reaction mechanisms were tested; the best model involved two subsequent hydrogenation steps. The first step yielded from trans,trans-muconic acid a monounsaturated intermediate (trans-2-hexenedioic acid), which was further hydrogenated to adipic acid in the second step. The intermediate was subjected to an equilibrium isomerization with cis-2-hexenedioic acid. The activation energy values and the rate constants were calculated for the reactions, providing the first reference for trans,trans-muconic acid hydrogenation.

A facile and sustainable functionalization of graphene layers was performed with pyrrole compounds (PyC) prepared through the Paal–Knorr reaction of a primary amine with 2,5-hexanedione. A good number of primary amines were used: hexanamine, dodecanamine, octadecanamine, 2-aminoacetic acid, 2-amino-1,3-propanediol, 3-(triethoxysilyl)propan-1-amine. The reactions were characterized by good yield, up to 96%, and indeed satisfactory atom efficiency, up to 80%. The functionalization of graphene layers was obtained by mixing PyC with a high surface area graphite and heating at a temperature range from 130°C to 150°C for 3 h. The yield of functionalization reaction was larger than 60% and also up to about 90% for the pyrrole compounds from dodecanamine and 2-amino-1,3-propanediol, respectively. The cycloaddition reaction between the graphene layers and the pyrrole compound, oxidized in two position, is proposed as working hypothesis to account for such efficient functionalization. Raman spectroscopy revealed that the structure of the graphitic substrate remained substantially unaltered, after the reaction. Stable dispersions of HSAG adducts with different PyC were prepared in solvents with different solubility parameters and HRTEM analysis showed the presence of aggregates of only few layers of graphene. Qualitative results of dispersion tests were used to calculate the Hansen sphere for the HSAG adduct with the pyrrole compound based on dodecanamine so to provide a first estimate of its Hansen solubility parameters. This work paves the way for the facile and sustainable modification of the solubility parameters of graphene layers and for the predictive assessment of their compatibility with different environments.