P-x data of (acetic acid + water) at T = (412.6, 443.2, 483.2) K

Experimental p–x data were measured for the (acetic acid + water) system at the temperatures (412.6, 443.2, and 483.2) K between the pressures 196 and 1902 kPa over the entire range of concentrations. Experiments were carried out in static-analytical equipment with quantitative analysis by GC. The experimental data were correlated with the Perturbed-Chain Statistical Associating Fluid Theory considering two association sites for acetic acid and four association sites for water

Evaluation of the Peng–Robinson and the Cubic-Plus-Association equations of state in modeling VLE of carboxylic acids with water

The performance of the classic Peng–Robinson (PR) and the modern Cubic-Plus-Association (CPA) equations of state were evaluated in modeling isobaric and isothermal vapor–liquid equilibria (VLE) of binary mixtures of carboxylic acids (formic, acetic, propanoic or butanoic) + water. Two functionalities of the alpha term were tested in PR, the original term proposed by Soave and the Matthias–Copeman term specially developed for modeling polar compounds. Within the Soave functionality, two generalized forms of the acentric factor were studied, the original general form and the Robinson and Peng modification for values of the acentric factor larger than 0.491. In addition, the case of PR with fitted parameters from saturated properties (as commonly obtained for modern equations of state) was also evaluated. VLE calculations without the use of a binary interaction parameter are in general more accurate with the modern CPA due to the association term; however, when a binary interaction parameter is used, the performance of the PR versions studied here are on average similar to those of CPA, and in some cases even superior. The original alpha function used in the PR equation and the original generalized form of the acentric factor are the best options for modeling organic acids + water systems when the binary interaction parameter is available. Temperature-dependent binary interaction parameters are provided as a database in modeling these complex systems

Comparative study on the hydrogenation of naphthalene over both Al2O3‑supported Pd and NiMo catalysts against a novel LDH-derived Ni-MMO-supported Mo catalyst

Naphthalene hydrogenation was studied over a novel Ni–Al-layered double hydroxide-derived Mo-doped mixed metal oxide (Mo-MMO), contrasted against bifunctional NiMo/Al2O3, and Pd-doped Al2O3 catalysts, the latter of which with Pd loadings of 1, 2, and 5 wt %. Reaction rate constants were derived from a pseudo-first-order kinetic pathway describing a two-step hydrogenation pathway to tetralin (k1) and decalin (k2). The Mo-MMO catalyst achieved comparable reaction rates to Pd2%/Al2O3 at double concentration. When using Pd5%/Al2O3, tetralin hydrogenation was favored over naphthalene hydrogenation culminating in a k2 value of 0.224 compared to a k1 value of 0.069. Ni- and Mo-based catalysts produced the most significant cis-decalin production, with Mo-MMO culminating at a cis/trans ratio of 0.62 as well as providing enhanced activity in naphthalene hydrogenation compared to NiMo/Al2O3. Consequently, Mo-MMO presents an opportunity to generate more alkyl naphthenes in subsequent hydrodecyclization reactions and therefore a higher cetane number in transport fuels. This is contrasted by a preferential production of trans-decalin observed when using all of the Al2O3-supported Pd catalysts, as a result of octalin intermediate orientations on the catalyst surface as a function of the electronic properties of Pd catalyst

Recycling of Bioplastics: Routes and Benefits

Continual reduction of landfill space along with rising CO2 levels and environmental pollution, are global issues that will only grow with time if not correctly addressed. The lack of proper waste management infrastructure means gloablly commodity plastics are disposed of incorrectly, leading to both an economical loss and environmental destruction. The bioaccumulation of plastics and microplastics can already be seen in marine ecosystems causing a negative impact on all organisms that live there, ultimately microplastics will bioaccumulate in humans. The opportunity exists to replace the majority of petroleum derived plastics with bioplastics (bio-based, biodegradable or both). This, in conjunction with mechanical and chemical recycling is a renewable and sustainable solution that would help mitigate climate change. This review covers the most promising biopolymers PLA, PGA, PHA and bio-versions of conventional petro-plastics bio-PET, bio-PE. The most optimal recycling routes after reuse and mechanical recycling are: alcoholysis, biodegradation, biological recycling, glycolysis and pyrolysis respectively

Vapor Equilibrium Data for the Binary Mixtures of Dimethyl Carbonate and Ethyl Methyl Carbonate in Compressed Carbon Dioxide

Phase equilibrium data for the binary systems of carbon dioxide + dimethyl carbonate and carbon dioxide + ethyl methyl carbonate were obtained. All systems were measured for isotherms ranging from 298.2 K to 328.2 K with pressure ranging between 0.13 MPa and 10.6 MPa. A static equilibrium technique was established with samples quantified using an offline method. The results were modeled using the Peng–Robinson equation of state with van der Waals one-fluid mixing rules

Vapour-liquid equilibrium of propanoic acid+water at 423.2, 453.2 and 483.2K from 1.87 to 19.38bar. Experimental and modelling with PR, CPA, PC-SAFT and PCP-SAFT

Vapour–liquid equilibrium data were measured for the propanoic acid + water system at 423.2, 453.2 and 483.2 K from 1.87 to 19.38 bar over the entire range of concentrations. An experimental apparatus based on the static–analytical method with sampling of both phases was used with quantitative analysis by GC. The system is highly non-ideal showing azeotropic behaviour. The Peng–Robinson (PR), the cubic plus association (CPA), the perturbed chain statistical associating fluid theory (PC-SAFT) and the PC-polar-SAFT (PCP-SAFT) equations of state modelled the data. Two association sites were assumed for both compounds. A single–binary interaction parameter (kij ) was used in all models, and predictive (kij=0) and correlative (View the MathML source) capabilities were assessed. Available data at 313.1, 343.2 and 373.1 K from the open literature were included in the analysis. PCP-SAFT presented higher predictive and correlative capabilities over the entire temperature range. PC-SAFT in predictive mode was not able to represent the azeotropic behaviour but resulted in the second best correlations. CPA presented a satisfactory balance between the two modes. PR predictions were rather poor but correlations were better than those of CPA, at the expense of a larger kij

Methanolysis of Poly(lactic Acid) Using Catalyst Mixtures and the Kinetics of Methyl Lactate Production

Polylactic acid (PLA) is a leading bioplastic of which the market share is predicted to increase in the future; its growing production capacity means its end-of-life treatment is becoming increasingly important. One beneficial disposal route for PLA is its chemical recycling via alcoholysis. The alcoholysis of PLA leads to the generation of value-added products alkyl lactates; this route also has potential for a circular economy. In this work, PLA was chemically recycled via methanolysis to generate methyl lactate (MeLa). Four commercially available catalysts were investigated: zinc acetate dihydrate (Zn(OAc)2), magnesium acetate tetrahydrate (Mg(OAc)2), 4-(dimethylamino)pyridine (DMAP), and triazabicyclodecene (TBD). Dual catalyst experiments displayed an increase in reactivity when Zn(OAc)2 was paired with TBD or DMAP, or when Mg(OAc)2 was paired with TBD. Zn(OAc)2 coupled with TBD displayed the greatest reactivity. Out of the single catalyst reactions, Zn(OAc)2 exhibited the highest activity: a higher mol% was found to increase reaction rate but plateaued at 4 mol%, and a higher equivalent of methanol was found to increase the reaction rate, but plateaued at 17 equivalents. PLA methanolysis was modelled as a two-step reversible reaction; the activation energies were estimated at: Ea1 = 25.23 kJ∙mol−1, Ea2 = 34.16 kJ∙mol−1 and Ea-2 = 47.93 kJ∙mol−1

Ethyl Lactate Production from the Catalytic Depolymerisation of Post‑consumer Poly(lactic acid)

Bioplastics such as poly(lactic acid) (PLA), which are derived from renewable sources, promoted as biodegradable and implemented for numerous functions, offer a promising alternative to the enduring synthetic plastics abundant in society. However, the degradation of PLA is slow under natural environmental conditions. A chemical recycling route is thus required to couple mitigation of plastic persistence repercussions with circular economy adherence. In the present work, the production of ethyl lactate by the catalysed transesterification of post-consumer PLA was investigated. The catalyst employed was a propylendiamine Zn(II) complex. The PLA samples investigated consisted of a phone case, an infant’s toy, a film, a cup and 3D printing material. Degradation reactions were studied at 50 °C and 90 °C and the concentrations measured at two different time intervals, 1 h and 3 h. The results revealed that greater activity of the catalyst was observed at 50 °C for two PLA samples (cup, 3D print). PLA film achieved the greatest lactate yield (71%) of all samples after 3 h at 50 °C. It is concluded that the propylenediamine Zn(II) catalyst can be used to produce green solvent ethyl lactate at mild temperatures from post-consumer PLA, even in the presence of unknown additives

Cross-sectional analysis of lithium ion electrodes using spatial autocorrelation techniques.

Join counting, a standard technique in spatial autocorrelation analysis, has been used to quantify the clustering of carbon, fluorine and sodium in cross-sectioned anode and cathode samples. The sample preparation and EDS mapping steps are sufficiently fast for every coating from two Design of Experiment (DoE) test matrices to be characterised. The results show two types of heterogeneity in material distribution; gradients across the coating from the current collector to the surface, and clustering. In the cathode samples, the carbon is more clustered than the fluorine, implying that the conductive carbon component is less well distributed than the binder. The results are correlated with input parameters systematically varied in the DoE coating blade gap, coating speed, and other output parameters coat weight, and electrochemical resistance

Zinc complexes for PLA formation and chemical recycling

A series of Zn II complexes, based on propylenediamine Schiff bases, have been prepared and fully characterized. X-ray crystallography and NMR spectroscopy identified significant differences in the solid and solution state for the Zn II species. All complexes have been applied to the ring-opening polymerization of l-lactide with emphasis on industrial conditions. High conversion and good molecular weight control were generally achievable for Zn(A–D) 2, and high-molecular-weight poly(lactic acid) (PLA) was prepared in 1 min at a 10 000:1:33 [lactide]/[Zn]/[BnOH] loading. The more active Zn II catalysts were also applied to PLA degradation to alkyl lactate under mild conditions. Zn(A–B) 2 demonstrated high activity and selectivity in this process with PLA being consumed within 1 h at 50 °C. Zn(C–D) 2 were shown to be less active, and these observations can be related to the catalysts’ structure and the degradation mechanism. Initial results for the degradation of poly(ethylene terephthalate) and mixed feeds are also presented, highlighting the broader applicability of the systems presented