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Sugar beet pulp (SBP) is a major byproduct from the sugar industries and consists of >20% w/w arabinose. The current work evaluated the potential of Enterobacter ludwigii assimilating pure arabinose and arabinose rich hydrolysate from SBP pellets for 2,3-butanediol (BDO) production. The hydrolysate was obtained through dilute acid pretreatment (DAP) with sulphuric acid. The process was optimized for acid and solid loading to obtain a hydrolysate free from furan derivatives. The effect of different levels of substrate (10–60 g/L) using pure arabinose was conducted in shake flask experiments, followed by co-fermentation with small amounts of glucose and SBP hydrolysate. After flask cultivations, BDO fermentations were carried-out in a bench-top bioreactor in batch and fed-batch modes using pure arabinose as well as SBP hydrolysate. The fed-batch culture led to BDO production of 42.9 and 35.5 g/L from pure arabinose and SBP hydrolysate with conversion yields of 0.31 and 0.29 g/g, respectively. Finally, BDO accumulated on pure arabinose and SBP hydrolysate were recovered using an aqueous two-phase extraction system. The recovery yield of BDO accumulated on arabinose and hydrolysate was ∼97%. The work demonstrated the feasibility of using SBP as a suitable feedstock for manufacturing BDO.

Abstract Phase equilibrium data ($$p$$ p , $$T$$ T , $$y$$ y ) 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. Graphical Abstract

JPhys energy 5(2), 021501 (2023). doi:10.1088/2515-7655/acaa57, Published by IOP Publishing, Bristol

Electronic waste (e-waste) has become one of the major causes of environmental concerns due to its large volume, high generation rate and toxic environmental burdens. Recent estimates put e-waste generation at about 54 million tonnes per annum with figures reaching approximately 75 million tonnes per annum by 2030. In this manuscript, the state-of-the-art technologies and techniques for segregation, recovery and recycling of e-waste with a special focus on the valorisation aspects of e-plastics and e-metals which are critically reviewed. A history and insight into environmental aspects and regulation/legislations are presented including those that could be adopted in the near future for e-waste management. The prospects of implementing such technologies in the State of Kuwait for the recovery of materials and energy from e-waste where infrastructure is lacking still for waste management are presented through Material Flow Analysis. The information showed that Kuwait has a major problem in waste accumulation. It is estimated that e-waste in Kuwait (with no accumulation or backlog) is generated at a rate of 67,000 tpa, and the imports of broadcasting electronics generate some 19,428 tonnes. After reviewing economic factors of potential recovered plastics, iron and glass from broadcasting devices in Kuwait as e-waste, a total revenue of $399,729 per annum is estimated from their valorisation. This revenue will open the prospect of ventures for other e-waste and fuel recovery options as well as environmental benefits and the move to a circular economy.

Landfilling is viewed nowadays as a serious threat associated with various burdens and stressors on the urban environment. To date, there is little information available on actual value of landfilled waste namely plastic solid waste (PSW) resulting from mining operations. In this work, PSW reclaimed from an active unsanitary landfill site (MAB) has been studied with the aim of determining its thermal profile and degradation behaviour for future utilisation in thermo-chemical conversion (TCC) processes. The materials were characterised by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) in accordance with internationally approved test methods in a simulated pyrolytic environment. In addition, chemical analysis using Fourier Transform Infrared Spectroscopy (FTIR) was applied to study the nature of the materials reclaimed. The degradation kinetics of the reclaimed PSW were studied with the aim of determining the apparent activation energy (Ea) of the pyrolytic reactions. The Ea values determined ranged from 199 to 266 kJ mol−1 which is in-line with pyrolytic reactions applicable for future use in fuel recovery units. TGA showed a clear shift in thermograms indicating a clear change in the degradation mechanism. The physico-chemical studies conducted on the materials also favours TCC treatment over other conventional end of life options such as physical (mechanical) recycling or incineration. The degradation mechanism was also determined from the Criado method showing that Avarami-Erofeve was the model that best represents PSW degradation. Overall, this work points towards future intervention schemes for reclaimed municipal solid waste (MSW) and in particular PSW favouring TCC technologies.

The performance of various association schemes was evaluated in modeling isothermal and isobaric vapor–liquid equilibria of mixtures of organic acids and water with the CPA and the PC-SAFT equation...

A process simulation and techno-economic evaluation of using molten solar salt as the heating medium for pyrolysis of mixed plastic waste (MPW) containing poly(vinyl chloride) (PVC) was performed. ...

A range of alkaline and weak Lewis acid solutions were used in conjunction with an acetone / water solvent system in order to decompose a carbon fibre reinforced epoxy resin. The initial concentration of the additives in the mixture was varied between 0.01 to 0.40 M at temperatures and pressures of 280 to 320 °C and 13 to 20 MPa. Under these conditions and a reaction time of 1 h, KOH and NaOH did not accelerate the decomposition of the matrix relative to the neat solvent, however, 0.05 M solutions of ZnCl2 and MgCl2 and a 0.005 M solution of AlCl3 facilitated the recovery of clean fibres at 300 °C. Under these conditions, the degradation achieved with acetone / water alone was just 33 wt%. By changing the process temperature and reaction time, the minimum necessary conditions for complete degradation were identified as 290 °C, 1.5 h or 300 °C, 45 min for all metal chlorides investigated. This represents a reduction in temperature of 40 °C when compared to a neat acetone / water solvent mixture. The reaction kinetics were studied through the application of a first order rate equation and a shrinking core model with the results demonstrating that 0.05 M ZnCl2 reduces the activation energy of the reaction by 30%. Analysis of the organic liquid fraction using infrared spectroscopy suggests that this is due to the cleavage of the C N bonds in the epoxy resin by the metal ions. Gas chromatography with mass spectrometry identified the presence of cyclic compounds and low concentrations of amine derivatives.

The poor solubility of curcumin (CURC) in aqueous media leads to a low bioavailability, which prevents its application in pharmaceutical formulations. In this work, the Supercritical Antisolvent process (SAS) was used to produce coprecipitates of CURC and poly (vinyl pyrrolidone) (PVP) from mixtures of ethanol and acetone. The effects of operating parameters: pressure, temperature, solution concentration, drug/polymer mass ratio and solution flow rate were analysed for a 70–30 (v/v) acetone-ethanol mixture. It was found that the composition of acetone in the solvent mixture is the parameter that affects particle size and curcumin recovery the most. The thermal behaviour, crystallinity, molecular interactions, apparent solubility, release profile of the coprecipitates and possible degradation of curcumin were investigated. The results showed that the SAS process is effective in preparing amorphous formulations of CURC/PVP with an apparent solubility of more than 600 times higher than that of the physical mixture of the raw compounds.

The decomposition of a carbon fibre reinforced epoxy resin with an acetone/water solvent supplied in the ratio of 80:20 v/v has been investigated using a non-stirred batch reactor. Temperatures and pressures in the range of 300–380 °C and 16–30 MPa were studied over a reaction time of up to 150 min using an initial reactor loading of 30 gresin Lsolvent−1. The minimum conditions necessary for effective fibre recovery were identified as 320 °C and 20 MPa. After processing for 120 min at this temperature and pressure, up to 95 wt.% of the resin was stripped from the fibre surface and the original weave architecture was retained. Increasing the reactor loading to 90 gresin Lsolvent−1 demonstrates no significant effect on the extent of resin decomposition. This, combined with imaging using X-ray computer tomography, suggests that the solvent is always in excess and that the mass transfer of the solvent into the composite and degradation products away from the surface is fast. A first order reaction rate equation based on the Arrhenius expression and a reaction-rate limited shrinking core model (SCM) have both been successfully fitted to the experimental data. From this, the parameters activation energy and frequency factor have been calculated to be 222.3 kJ mol−1 and 7.64 × 1017 min−1 respectively for the Arrhenius model and 164.3 kJ mol−1 and 1.29 × 1012 min−1 for the SCM. The results presented in this work demonstrate that either approach can be used to predict the resin decomposition to within ±5% which is similar to the margin of experimental error.

The dechlorination of chlorine containing hydrocarbons in pyrolysis vapor is poorly understood. In order to shed new light on the dechlorination mechanism, a model mixture composed of iso-octane doped with 2-chlorobutane, 2-chloroethylbenzene, and chlorobenzene was used to study the dechlorination of chlorinated hydrocarbons by alkali adsorption. These three chlorinated hydrocarbons were selected as they can be typically produced from the pyrolysis of mixed plastic waste containing polyvinyl chloride (PVC). The mixture is pumped continuously through a Na₂CO₃ or CaCO₃/alumina bed, and GC-MS is used to identify the dechlorination products and to follow the dechlorination reactions. When chlorine is bonded to an aliphatic carbon with an adjacent aliphatic hydrogen, the chlorinated compound first undergoes a dehydrochlorination reaction to form HCl and olefins, and subsequently the HCl is reacted with the alkali in the absorbents. In our experiments, 2-chlorobutane is converted to 2-butene, and 2-chloroethylbenzene is converted to styrene. The formation of HCl and subsequent reaction with alkali components in the absorbent is verified by IR spectroscopy and XRD. In the presence of an alkali, the aliphatic chlorinated hydrocarbons underwent dechlorination at a temperature of 180 °C. The removal of chlorine from aromatic chlorinated compounds operates in a different mechanism, in which the C–Cl bond scission is promoted significantly by the presence of an alumina and hydrocarbon medium. It was found that chlorobenzene undergoes dechlorination forming phenol and benzene.

Background Xylitol is a commercially important chemical with multiple applications in the food and pharmaceutical industries. According to the US Department of Energy, xylitol is one of the top twelve platform chemicals that can be produced from biomass. The chemical method for xylitol synthesis is however, expensive and energy intensive. In contrast, the biological route using microbial cell factories offers a potential cost-effective alternative process. The bioprocess occurs under ambient conditions and makes use of biocatalysts and biomass which can be sourced from renewable carbon originating from a variety of cheap waste feedstocks. Result In this study, biotransformation of xylose to xylitol was investigated using Yarrowia lipolytica, an oleaginous yeast which was firstly grown on a glycerol/glucose for screening of co-substrate, followed by media optimisation in shake flask, scale up in bioreactor and downstream processing of xylitol. A two-step medium optimization was employed using central composite design and artificial neural network coupled with genetic algorithm. The yeast amassed a concentration of 53.2 g/L xylitol using pure glycerol (PG) and xylose with a bioconversion yield of 0.97 g/g. Similar results were obtained when PG was substituted with crude glycerol (CG) from the biodiesel industry (titer: 50.5 g/L; yield: 0.92 g/g). Even when xylose from sugarcane bagasse hydrolysate was used as opposed to pure xylose, a xylitol yield of 0.54 g/g was achieved. Xylitol was successfully crystallized from PG/xylose and CG/xylose fermentation broths with a recovery of 39.5 and 35.3%, respectively. Conclusion To the best of the author’s knowledge, this study demonstrates for the first time the potential of using Y. lipolytica as a microbial cell factory for xylitol synthesis from inexpensive feedstocks. The results obtained are competitive with other xylitol producing organisms.

The increasing global waste plastic pollution is urging people to take immediate actions on effective plastic recycling and processing. In this work, we report the results of processing reclaimed plastic wastes from unsanitary landfill site in Kuwait by using a bench scale continuous auger pyrolysis system. The plastic feedstock was characterised. After a simple thermal densification process, the material was fed to the pyrolysis system at 500 °C. The pyro-oil and wax products were collected and characterised. The process mass balance was developed on dry basis, and the yields of pyro-oil, light wax, heavy wax and gases were 5.5, 23.8, 69.4 and 1.3 wt%, respectively. The findings have indicated that the reclamation of plastic waste from landfill was feasible in terms of the product distribution and characteristics. Further liquid analysis confirmed that the liquid products contained fractions that are comparable to petrol and diesel fuels. The wax products are viable and have potential application as coating, covering and lubrication.

Background: Xylitol is a commercially important chemical with multiple applications in food and pharmaceutical industries. According to the US Department of Energy, xylitol is among the twelve platform chemicals that can be produced from biomass. The chemical method for xylitol synthesis is however expensive and energy intensive. In contrast, the biological route involving microbial cell factories offers a potential cost-effective alternative process. The bioprocess occurs under ambient conditions and makes use of biocatalysts which can be sourced from renewable carbon coming from a variety of cheap feedstocks classified as wastes. Result: In this study, biotransformation of xylose to xylitol was investigated using Yarrowia lipolytica an oleaginous yeast grown on glycerol/glucose screening of primary carbon source, media optimisation in shake flask, scale up in bioreactor and downstream processing of xylitol were carried out. With the two step medium optimization involving central composite design and artificial neural network coupled with genetic algorithm, the yeast amassed 53.2 g/L of xylitol using glycerol and xylose with a bioconversion yield of 0.97 g/g. Similar results were obtained when pure glycerol was substituted with crude glycerol from biodiesel industry (titer: 50.5 g/L; yield: 0.92 g/g). Even when xylose from lignocellulosic hydrolysate was used as opposed to pure xylose, a xylitol yield of 0.54 g/g was achieved. Xylitol was successfully crystallized from fermented broth using pure glycerol/xylose and crude glycerol /xylose with a recovery of 35 and 39.45%, respectively. Conclusion: To the best of the author’s knowledge, this is the first study demonstrating the potential of Y. lipolytica as microbial cell factory for xylitol synthesis from inexpensive feedstocks. The results obtained are competitive with other xylitol producing organisms.

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.

Hydrogen, an emergent alternative energy vector to fossil fuels, can be produced sustainably by fermentation of cellulose following hydrolysis. Fermentation feedstock was produced hydrolytically using hot compressed water. The addition of CO2 enhanced hydrolysis by ~26% between 240 and 260 C with comparable hydrolysis products as obtained under N2 but at a 10 C lower temperature. Co-production of inhibitory 5-hydromethyl furfural was mitigated via activated carbon sorption, facilitating fermentative biohydrogen production from the hydrolysate by Escherichia coli. Post-fermentation E. coli cells were recycled to biomanufacture supported Pd/Ru nanocatalyst to up-convert liquid-extracted 5-HMF to 2,5-dimethyl furan, a precursor of ‘drop in’ liquid fuel, in a one-pot reaction. This side stream up-valorisation mitigates against the high ‘parasitic’ energy demand of cellulose bioenergy, potentially increasing process viability via the coupled generation of two biofuels. This is discussed with respect to example data obtained via a hydrogen biotechnology with catalytic side stream up-conversion from cellulose feedstock., UK Research & Innovation (UKRI), Engineering & Physical Sciences Research Council (EPSRC) EP/D05768X/1 EP/E034888/1, Biotechnology and Biological Sciences Research Council (BBSRC) BB/C516195/2 BB/E003788/1, Natural Environment Research Council (NERC) NE/L014076/1, Royal Society of London, European Commission, Government of Mexico 203186, Spanish Government Sistema Nacional de Garantia Juvenil grant (Promocion de Empleo Joven e Implantacion de la Garantia Juvenil 2014, MINECO) PEJ-2014-P-00391, General Electric POC46

The solubilities of hardly soluble solutes in compressed CO2 were measured using a new static precise mass measuring (SPMM) method. The solubilities of two solutes—azoxystrobin, a substituted pyrim...

Industrial solid waste management encompasses a vital part of developed and developing countries strategies alike. It manages waste generated from vital industries and governs the hazardous waste generated as a major component of integrated waste management strategies. This article reviews the practices that govern the management approaches utilized in the developed world for industrial spent catalysts. It critically assesses the current situation of waste management within the developing world region focusing on the industrial waste component, in a novel attempt to crucially develop a strategy for a way forward based on best practices and future directions with major European industries. The review also draws parallels with European countries to compare their practices with those of the State of Kuwait, which rely solely on landfilling for the management of its industrial waste. Spent catalysts recovery methods are discussed at length covering conventional methods of valuable metals and chemicals recovery (e.g., hydrometallurgical, solid–liquid and liquid–liquid extraction) as well as biological recovery methods. A major gap exists within regulations that govern the practice of managing industrial waste in Kuwait, where it is essential to start regulating industries that generate spent catalysts inview of encouraging the establishment of valorization industries for metal and chemical recovery. This will also create a sustainable practice within state borders, and can reduce the environmental impact of landfilling such waste in Kuwait. Industrial solid waste management encompasses a vital part of developed and developing countries strategies alike. It manages waste generated from vital industries and governs the hazardous waste generated as a major component of integrated waste management strategies. This article reviews the practices that govern the management approaches utilized in the developed world for industrial spent catalysts. It critically assesses the current situation of waste management within the developing world region focusing on the industrial waste component, in a novel attempt to crucially develop a strategy for a way forward based on best practices and future directions with major European industries. The review also draws parallels with European countries to compare their practices with those of the State of Kuwait, which rely solely on landfilling for the management of its industrial waste. Spent catalysts recovery methods are discussed at length covering conventional methods of valuable metals and chemicals recovery (e.g., hydrometallurgical, solid-liquid and liquid-liquid extraction) as well as biological recovery methods. A major gap exists within regulations that govern the practice of managing industrial waste in Kuwait, where it is essential to start regulating industries that generate spent catalysts in-view of encouraging the establishment of valorization industries for metal and chemical recovery. This will also create a sustainable practice within state borders, and can reduce the environmental impact of landfilling such waste in Kuwait.

Experimental – data were measured for the (acetic acid + water) system at the temperatures of (412.6, 443.2 and 483.2) K between the pressures of 196 kPa and 1902 kPa over the entire range of concentrations. Experiments were carried out in a 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.

The pyrolysis of urban chlorine-containing polyolefinic plastic waste with simultaneous retention of HCl is investigated. Different chemical removers based on sodium, calcium and zinc bases, and different adsorbents based on alumina or zeolites were used inside the reactor or in downstream hot filters, respectively, for chlorine removal and upgrading of pyrolysis oils. Initially, polyolefin waste (POW, containing a 98.5 wt% polyolefins) was thermogravimetrically pyrolyzed to determine its thermal behaviour. Subsequently, chemical removers were mixed with the POW which was pyrolyzed at 480 °C in a semi-batch reactor. The adsorbents were tested separately in hot filters (300 ± 20 °C) downstream of the pyrolysis reactor. After the pyrolysis, the resulting char containing the chemical removers and the absorbents in the hot filters were analysed by FTIR, CHN elemental analysis and ESEM-EDS to determine their respective chlorine contents. The highest chlorine retention was 23.8 wt% for chemical remover when used in direct contact with POW, while a zeolite used in the hot filter (gas streams) gave a chlorine retention of 65.6 wt%. The pyrolytic liquids consisted of mixtures of C7-C40 hydrocarbons made up of olefinic and aliphatic hydrocarbons with a very low presence of aromatics (estimated to be below 3 wt% by HPLC). In most cases, the chlorine removal processes resulted in waxier pyrolytic oils and with a higher degree of branching.

A powder characterization method was developed to screen the ability of a range of chemicals and absorbents to retain chlorine from chlorinated plastic pyrolysis. The behaviour of adsorbents such as Al2O3 and zeolites, and chemical removers based on NaHCO3, CaO and Na2CO3-ZnO were studied for the removal of HCl released during PVC pyrolysis. First, chlorine removers are mixed with PVC and tested in a thermobalance under pyrolysis conditions for the complete PVC dehydrochlorination (550 °C). Subsequently, after the release of HCl, CO2 and H2O, the chars are analysed by FTIR, CHN elemental analysis and ESEM-EDS to determine the retention of chlorine on the chlorine removers. According to FTIR and CHN, PVC pyrolysis occurs through dehydrochlorination and the formation of aromatics. FTIR and EDS were used to follow the consumption of the bases present in the chemical removers and the suppression of the C Cl absorption bands of the PVC CHCl groups during pyrolysis, as well as the formation of the resulting salts (NaCl, CaCl2 and ZnCl2). The chemical removers exhibited chlorine retentions of up to 71 wt. % (using Na2CO3-ZnO), while the adsorbents presented a maximum of 19 % of retention at 550 °C and heating rate of 200 °C/min.

Common strategies to improve the dissolution properties of hydrophobic drug compounds include the preparation of composites with hydrophilic excipients and/or size reduction. However, nanoparticles have poor flowability and difficult handling. Therefore, this work aims to demonstrate the single-step improvement of dissolution and flow properties of pharmaceutical formulations. Coprecipitates of curcumin and poly (vinyl pyrrolidone) (guest particles) are simultaneously produced and coated onto microcrystalline cellulose (MCC, 175 μm), corn starch (15 μm) and lactose (

We describe a novel method of Polyhydroxyalkanoate (PHA) extraction using dimethyl sulphoxide (DMSO) for use in screening studies. Compared to conventional chloroform extraction, the DMSO method was shown to release comparable quantities of PHA from Cupriavidus necator cells, with comparable properties as determined using Fourier transform infrared spectroscopy and differential scanning calorimetry.

Ultradispersed particles of a size less than 100 nm for in situ catalytic upgrading have been reported to outperform the augmented catalytic upgrading achieved by incorporating pelleted refinery catalyst to the horizontal production well of the toe-to-heel air injection (THAI) process. Hydroconversion of heavy oil was carried out in a stirred batch reactor at 425 °C, 50 bar (initial H2 pressure), 900 rpm, and 60 min reaction time using a range of unsupported transition metal (Mo, Ni, and Fe) catalysts. The effect of metal nanoparticles (NPs) was evaluated in terms of product distribution, physical properties, and product quality. The produced coke and recovered catalysts were also studied. The levels of API gravity and viscosity of the upgraded oils observed with the NPs was approximately 21° API and 108 cP compared with thermal cracking alone (24° API and 53.5 cP); this moderate upgrade with NPs is due to the lack of cracking functionality offered by supports such as zeolite, alumina, or silica. However,...

By designing dyes with fluoroalkyl groups, the optical and electronic properties of the alkyl analogue were maintained while dramatically altering the solubility. Dyes, F-TABTA (8) and its masked derivative F-TABTSi (9), that enable them to be deposited under conventional organic solvent and scCO2 conditions, respectively, were developed. In liquid DSSC devices, the fluoroalkyl dye (F-TABTA, 8) performs slightly better than its alkyl analogue (D21L6, 10), and interestingly, it was found that the former device showed better stability over time. Deploying the silyl-masked precursor F-TABTSi (9), this dye was deposited onto TiO2 photoanodes from scCO2 in very short contact times (2.5 h), and ECEs of 7.70% were obtained that exceed the performance of the alkyl dye when deposited by conventional methods.

The replacement of diesel by biofuels is considered unrealistic because of the land used to produce their feedstock. One appointed solution is the use of algae which have higher productivity per unit area when compared with other feedstocks. In light of this, the total area, including water and land required for the European Union (EU), the United States (US), and Brazil was determined using international policies and targets, the present and future diesel demand, the current biodiesel production (released by international organizations), and specific data of algae productivity from the literature. GIS software was used to locate possible cities where algae cultivation could occur nearby. Bearings on the availability of area (flat and unoccupied zones), favourable climate, proximity to the process inputs (such as nutrients (preferably from municipal waste water treatment), CO 2 and water sources) and political boundaries were used as assessment criteria. It was possible to identify seven suitable cities with more than 500,000 inhabitants in the EU, two in the USA and thirteen in Brazil. It was also shown that it is possible to attain targets required by current policies and replace diesel with algae-derived diesel based on attainable cultivation areas.

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 ( k i j = 0 ) and correlative ( k i j = k i j 0 + k i j 1 T ) 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.

The reaction of methanol to propene was studied in a fixed bed reactor using a pelleted zeolite in alumina matrix support catalyst. The effect of reaction conditions (temperature, pressure, space velocity, feed composition), as well as the effect of support to ZSM-5 zeolite ratio on the conversion of methanol to light olefins (C2 –C4 ) was studied. The best catalyst and optimum reaction conditions leading to a maximum yield of C2 –C4 were determined. Use of γ-alumina as support improved the catalyst selectivity to propene and light olefins. Zeolite/alumina catalyst with 25 wt.% ZSM-5 dispersed in a matrix containing 75% alumina led to highest selectivity to propene and light olefins. ZSM-5 zeolite was modified with phosphorus, Cs, Ca and Fe. The effect of their impregnation on the conversion of methanol and selectivity to light olefins was studied. Modification in all cases increased the shape-selectivity to light olefins. ZSM-5 zeolite ion exchanged by Cs led to highest selectivity to light olefins and particularly propene by changing the acid sites distribution.

Dry powder formulations with potential application in pulmonary drug delivery were produced by integrating the Supercritical Antisolvent (SAS) process with a fluidized bed (FB) under pressure. The simultaneous precipitation and coating of curcumin on lactose was performed in a single step combining the advantages of both processes. Ethanol and acetone were used as solvents. The effects of operating parameters: pressure, temperature, drug-lactose mass ratio, solution flow rate and solution concentration on the drug size, morphology and yield were investigated. Due to the high degree of mixing in the fluidized bed, a uniform coating of curcumin onto lactose was achieved with loading efficiency varying from 71.0 to 93.3% and curcumin particle size between 0.41 and 12.08 μm. Solvent-free curcumin particles with reduced crystallinity were produced while the physicochemical properties of the raw materials were not changed.

Cider lees, a microbial by-product of the cider industry which is primarily comprised yeast cells was subjected to subcritical water mediated hydrolysis using a batch tubular reactor over a temperature range of 175–275 °C. The efficacy of subcritical water to hydrolyse the polysaccharides and mannoproteins in the yeast's cell wall to monosaccharides and for the glucose and mannose to be dehydrated to 5-hydroxymethylfurfural (HMF) was investigated in a non-catalysed reaction using a consecutive first order kinetic model. Results suggest that the cider yeast cell wall, which is backboned by milder bonds, was decomposed at lower temperatures when compared to cellulose hydrolysis under the same conditions. Glucose and mannose formation was observed at temperatures as low as 175 °C and their conversion to HMF at 225 °C resulted the yield of more than 12%, based on the crude feedstock. Reaction rates for other decomposition routes were also calculated and discussed using the developed model.

A single screw extrusion process in which CO2 is injected into the polymer melt has been utilized to produce low density biodegradable poly(DL-lactic acid) (PDLLA) foams. High pressure differential scanning calorimetry (DSC) and rheology are used to observe the melting point and viscosity depression of PDLLA 3051D in the presence of CO2. Foams of PDLLA 3051D are produced in a static environment under a range of conditions, and these data are utilized to extrude PDLLA 3051D into foamed sheets for packaging applications. The density, crystallinity, mechanical properties and microstructure of these foams are evaluated.

Production of active ingredients such as pharmaceuticals in nano-particulate form is highly desirable but the resulting product is difficult to handle and to use in applications. A novel process is described for coating nanoparticles onto excipient particles of c. 300 μm by rapid expansion of a supercritical solution (RESS) into two types of modified proprietary equipment: a Wurster coater and a fluidized bed. This novel approach has been demonstrated through the successful deposition of six mimics for active ingredients (benzoic acid, adamantane, ferrocene, phenanthrene, stearic acid and vitamin K3) on carrier excipient particles of microcrystalline cellulose (MCC). Evidence from SEM, EDX and Confocal Raman microscopy suggests that the coating particles are below 30 nm in size. Unlike most conventional coating processes, this approach avoids the use of liquids and high temperatures. As a wide range of actives and excipients can potentially be employed, the approach is applicable across the process and product industries, in particular pharmaceutical, household goods, personal care and catalyst industries.

The crystallisation of Active Pharmaceutical Ingredients (API) from conventional organic solvents can yield undesirable crystal habits with poor physical properties that cause downstream processing problems. It has been proposed that ionic liquids (ILs) may offer an opportunity to perform controlled crystallisations from this media. Using paracetamol and the ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6] and 1-hexyl-3-methylimidazolium hexafluorophosphate [hmim][PF6] fundamental understanding of these systems was established by determining the Meta-stable Zone Width (MSZW) before completing a series of cooling crystallisations investigated across a temperature range between 20 °C and 90 °C. It has been shown that paracetamol can be crystallised from these systems to obtain the stable monoclinic form I and that the particle habit and size can be manipulated by changing the IL used, the solution concentration and the mechanism of crystal growth and in some cases crystal habits not commonly found from aqueous or organic solvents were produced. The results demonstrate that ILs may be a viable approach to manipulate crystal properties and should be explored more widely as a potential media for crystallisation of API.

Toe-to-heel air injection (THAI) and its catalytic version CAPRI are relatively new technologies for the recovery and upgrade of heavy oil and bitumen. The technologies combine horizontal production well, in situ combustion, and catalytic cracking to convert heavy feedstock into light oil down-hole. The deposition of asphaltenes, coke, and metals can drastically deactivate the catalyst in the CAPRI process. A fixed bed microreactor was used to experimentally simulate the conditions in the catalyst zone of the oil well of CAPRI. In this study, oil upgrading and catalyst deactivation in the CAPRI process were investigated in the temperature range of 350–425 °C, pressure of 20 barg and residence time of 9.2 min. Additionally, a guard bed consisting of activated carbon particles prior to the active catalyst in a microreactor and/or the addition of hydrogen to the gas feed were used to minimize coke formation and catalyst deactivation through respectively removing and hydrocracking the coke precursors. It was ...

Biodiesel, which is derived from oil/fat by transesterification with alcohol, has attracted considerable attention over the past decades due to its ability to subsidise fossil fuel derived energy as a renewable and carbon neutral fuel. Several approaches for biodiesel fuel production have been developed, among which transesterification using a catalyst gives high yields of methyl ester. This method has therefore been widely utilized for biodiesel production in a number of countries. In this study, a Downflow Liquid Contactor Reactor (DLCR) has been used for the liquid–liquid transesterification reaction of sunflower oil with alcohol with extraordinary results. The reactor provides great potential for chemical reactions, which are normally limited by mass transfer and possesses a number of distinctive advantages over conventional multiphase reactors. Inside the reactor a high velocity liquid jet stream is produced which generates powerful shear and energy, causing vigorous agitation in the upper part of the reactor. The high mixing intensity in the DLCR enabled the manufacture of biodiesel to European Standard EN14214 (ester content 96.5%) in 2.5 min at 40 °C with 0.43 wt.% alkali catalyst and alcohol to oil molar ratio of 4.5 to 1.0. The separation of FAME from glycerol is done by gravity settling only without water washing. The effect of the alcohol type (methanol, ethanol) on biodiesel yield was also investigated. The process offers the advantage of continuous large scale production with limited reactor volume.

A high pressure parallel plate rheometer is utilised to probe the rheological properties of polycaprolactone (PCL) over a range of temperatures (80–120 °C) and CO2 pressures (atmospheric to 100 bar). Interpretation of storage/loss modulus against angular frequency plots show that the reptation time of PCL can be significantly reduced by the addition of 60 bar CO2. This reduction is equivalent to heating the polymer by 20 °C. Application of a time/temperature superposition, coupled with the Arrhenius equation, shows that the addition of CO2 also lowers the activation energy to flow from 31.3 to approximately 21 kJ mol−1.

Poly(lactic acid) (PLA) is gaining increasing interest from the packaging industry as a biodegradable alternative to oil based polymers such as polypropylene (PP) and polyethylene terephthalate (PET). However, its’ inherent brittle nature prevents widescale commercial use. Blending in order to improve the Young’s modulus, yield stress and elongation to break, provides a possible alternative although many polymers have been found to be immiscible with PLA. In this study, high pressure carbon dioxide (CO 2 ) was utilised during blending to encourage miscibility between two normally immiscible polymers: poly(e-caprolactone) (PCL) and poly(lactic acid) (PLA). Blends were prepared by melt blending in the presence of carbon dioxide (CO 2 ) and compared to solvent casting and melt blending with a single-screw extruder. CO 2 assisted blends demonstrated a significant reduction in the size and number of PCL domains in a PLA matrix, and consequently improved the adhesion between phases at the microscale. The optimum melt blend composition for Young’s modulus, yield stress and elongation to break was found to be 75% PLA and 25% PCL. Mechanical properties of PLA 2002D blends were further improved when prepared by CO 2 assisted melt blending.

The dialkylation of naphthalene with isopropanol to produce 2,6-diisopropylnaphthalene (2,6-DIPN) was carried out over HY zeolite. The effects of various reaction conditions, such as pressure, temperature, space velocity, molar ratio of alcohol to naphthalene and time on stream (TOS) on product distribution were studied. HY zeolite was modified by transition metals, such as Fe 3+ , Ni 2+ , Co 2+ and Cu 2+ using wet impregnation method to maximize the selectivity to 2,6-DIPN. The catalysts were characterized by XRF, XRD, TGA, nitrogen adsorption–desorption and Temperature Programmed Desorption (TPD) of t-Butylamine. Under optimum reaction conditions, (50 bar, 220 °C, isopropanol/naphthalene = 4 (mole ratio), WHSV = 18.8 h −1 , TOS 6 h), HY zeolite modified by Fe 3+ was found to give the highest selectivity, by increasing the 2,6/2,7-DIPN ratio from 2.8 to 6.6. The experimental results indicate that the selectivity to 2,6-DIPN is in the order of Fe–HY > Ni–HY > Cu–HY > Co–HY > HY. Naphthalene conversion of 77% was obtained over HY zeolite, while after modification by Fe, Co, Ni and Cu, the conversion was changed to 73%, 76%, 88% and 96%, respectively. TPD result indicates different distribution of weak, medium and strong acid sites in the modified catalysts. TGA analysis of used catalyst samples revealed that a higher amount of PIPN was produced on zeolite modified by Co and Cu. This confirms that PIPN molecules are possible coke precursors, and therefore led to larger amount of coking on the Co–HY and Cu–HY catalysts.

The effect of supercritical CO2 on the viscosity and activation energy to viscous flow of PDLLA is investigated, using a high pressure parallel plate rheometer, over a range of temperatures (50–140 °C) and pressures (5–12 MPa). The Cross model is fitted to the data to enable calculation of the zero shear viscosity and critical shear rate. A significant decrease in the viscosity is observed on increasing both variables; however, at high temperatures, the pressure effect becomes negligible. An increase in the critical shear rate is also observed on raising the pressure, indicative of a reduction in the relaxation time of the polymer. Manipulation of the Arrhenius equation shows a reduction in the activation energy to viscous flow as the pressure is increased. Together, these results show that the melt processing temperature of PDLLA can be reduced in the presence of supercritical and high pressure CO2. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012

The use of supercritical CO2 to facilitate the processing of polymers is becoming increasingly popular. In light of this, it is important to understand the effect supercritical CO2 has on these polymers especially in terms of glass transition temperature and melting point depression and the induction of crystallization. The aim of the current study is to use infrared spectroscopy to probe these properties. Plaques of polycaprolactone were exposed to supercritical CO2 at a range of temperatures (41–60 °C) and pressures (0–200 bar). Examination of the carbonyl peak at 1720 cm−1 at 41 °C while increasing the pressure shows a change in morphology at 100 bar, indicative of a melting point. This is a 22°C reduction in the melting point compared with atmospheric pressure. Repetition of this experiment over a range of temperatures shows that the pressure required to induce melting reduces as the temperature is increased. Infrared spectroscopy is also used to observe the crystallization of polycaprolactone during the depressurization of CO2. Infrared spectroscopy is used to probe the melting point depression and crystallization of polycaprolactone in the presence of supercritical CO2. Comparison of the amorphous and crystalline peaks at 41 °C shows a melting point at 100 bar CO2. Increasing this temperature further reduces the pressure required to melt polycaprolactone. Infrared spectroscopy is also used to probe the crystallization of polycaprolactone during CO2 venting.