Co-Pyrolysis of Low-Density Polyethylene and Motor Oil—Investigation of the Chemical Interactions between the Components

In this work, different thermal analysis methods have been used to study the co-pyrolysis of low-density polyethylene (LDPE) and motor oil. Two kinds of motor oil were considered, a fresh one and a used one. Through the comparison of experimental curves and so-called “theoretical curves”, high-resolution thermogravimetry experiments allowed highlighting interactions between the LDPE and each of the two oils, when they are co-pyrolyzed. While thermogravimetry coupled with mass spectrometry did not give any insights into these interactions, pyrolysis coupled to gaseous chromatograph and mass spectrometry allowed identifying aldehydes in the products of the co-pyrolysis of LDPE and each of the two oils. These aldehydes were not observed during the pyrolysis of the LDPE or the oils alone. On the basis of these results, various explanations for the formation of these aldehydes are proposed

Development of a Continuous "Self-seeding" Microfluidic Crystallization Device for Active Pharmaceutical Ingredients

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On the effect of flow restrictions on the nucleation behavior of molecules in tubular flow Nucleators

This paper discusses theoretical and experimental considerations of organic molecules nucleating inside tubular reactors or nucleators. Temperature evolution of these liquid systems is experimentally shown for different flow rates as a function of distance when these nucleators are immersed into a water bath set at spontaneous nucleating conditions. When different restrictions in the flow path are introduced before the cooling phase of the liquid; important differences on the nucleation rates are observed. For this study, Aspirin was dissolved in a blend of water and ethanol in a 50/50 vol%. At a concentration of 200 mg/mL and a nucleation temperature of 10 °C, demonstrated to be close to the metastable zonewidth, these flow restrictions show an antagonistic effect on the nucleation rate. One restriction, placed right before the nucleator enters the cooling bath, induces a reduction in nucleation rate. Putting more restrictions into the flow path with an equal separation of 5 cm in between, the nucleation recovers back to its initial value when a second restriction of an expansion ratio 2 is applied. Restrictions with an expansion ratio of 4 exceed this nucleation rate up to an order of magnitude when more than 2 restrictions are put in place. At a higher kinetic driving force defined KDF, at a concentration of 300 mg/mL of Aspirin, the influence of the restriction becomes invariant as a function of the expansion ratio. For all experiments, the nucleation rates is highly increased with the number of restrictions introduced into the flow path. A thermal gradient difference by using the restrictions on the cooling rate of the liquid flowing inside the tubing was not observed experimentally. Therefore only hydrodynamic changes of the flow seems a plausible cause for this nucleation rate - restriction dependence as it is expected that finite amplitude perturbations, amplified by the use of restrictions, cause vortex shedding in current experimental setup. [Figure not available: see fulltext.].SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Self-seeding effect of particle clusters for microfluidic crystallization

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The coupling of in-flow reaction with continuous flow seedless tubular crystallization

The direct coupling between a continuous flow-assisted acetylation reaction of salicylic acid and the subsequent crystallisation of aspirin in a continuous flow tubular reactor or nucleator is investigated. The design of the reactor relies on a 3 minute residence time, followed by quenching with water prior to cooling inside the tubular nucleator. By appropriate selection of the temperature of the nucleation step, the number of nuclei formed in the tubular setup is accurately controlled. In this way, pure crystalline aspirin is continuously obtained with a desired mean crystal size between 3 μm and 300 μm and a reduced dispersion grade, avoiding seeding and micronisation steps.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Development of a continuous “self-seeding” microfluidic crystallization device for active pharmaceutical ingredients

info:eu-repo/semantics/nonPublishe

Method for improving nucleation of crystals from solution

info:eu-repo/semantics/publishe

Production of an alternative fuel by the co-pyrolysis of landfill recovered plastic wastes and used lubrication oils

This work is a preliminary study for the development of a co-pyrolysis process of plastic wastes excavated from a landfill and used lubrication oils, with the aim to produce an alternative liquid fuel for industrial use. First, thermogravimetric experiments were carried out with pure plastics (HDPE, LDPE, PP and PS) and oils (a motor oil and a mixture of used lubrication oils) in order to highlight the interactions occurring between a plastic and an oil during their co-pyrolysis. It appears that the main decomposition event of each component takes place at higher temperatures when the components are mixed than when they are alone, possibly because the two components stabilize each other during their co-pyrolysis. These interactions depend on the nature of the plastic and the oil. In addition, co-pyrolysis experiments were led in a lab-scale reactor using a mixture of excavated plastic wastes and used lubrication oils. On the one hand, the influence of some key operating parameters on the outcome of the process was analyzed. It was possible to produce an alternative fuel for industrial use whose viscosity is lower than 1 Pa s at 90°C, from a plastic/oil mixture with an initial plastic mass fraction between 40% and 60%, by proceeding at a maximum temperature included in the range 350–400°C. On the other hand, the amount of energy required to successfully co-pyrolyze, in lab conditions, 1 kg of plastic/oil mixture with an initial plastic mass fraction of 60% was estimated at about 8 MJ. That amount of energy is largely used for the thermal cracking of the molecules. It is also shown that, per kg of mixture introduced in the lab reactor, 29 MJ can be recovered from the combustion of the liquid resulting from the co-pyrolysis. Hence, this co-pyrolysis process could be economically viable, provided heat losses are addressed carefully when designing an industrial reactor.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Co-pyrolysis of low-density polyethylene and motor oil—investigation of the chemical interactions between the components

In this work, different thermal analysis methods have been used to study the co-pyrolysis of low-density polyethylene (LDPE) and motor oil. Two kinds of motor oil were considered, a fresh one and a used one. Through the comparison of experimental curves and so-called “theoretical curves”, high-resolution thermogravimetry experiments allowed highlighting interactions between the LDPE and each of the two oils, when they are co-pyrolyzed. While thermogravimetry coupled with mass spectrometry did not give any insights into these interactions, pyrolysis coupled to gaseous chromatograph and mass spectrometry allowed identifying aldehydes in the products of the co-pyrolysis of LDPE and each of the two oils. These aldehydes were not observed during the pyrolysis of the LDPE or the oils alone. On the basis of these results, various explanations for the formation of these aldehydes are proposed.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Stereochemistry Driven Cocrystallisation Phenomena in Partially Cycloaliphatic Polyamides

Two series of isomeric copolyamides were synthesised, viz. polyamides 12.6 for which the adipic acid residues were partially replaced by cis/trans-1,4-cyclohexanedicarboxylic acid (1,4-CHDA), and polyamides 4.14 for which the 1,4-diaminobutane residues were partially replaced by cisltrans-1,4-diaminocyclohexane (1,4-DACH). A careful DSC and WAXS analysis learned that only the trans isomers of both 1,4-DACH and 1,4-CHDA are incorporated into the crystalline phase. During DSC analysis, an intitial high trans content is preserved in the case of the non-isomerising 1,4-DACH, whereas the 1,4-CHDA residues gradually isomerise from a high initial trans content to a significanly lower trans content. Since these cis residues are not incorporated into the crystalline domains, the lower second heating melting points of the 1,4-CHDA-based copolyamides in comparison with 1,4-DACH-based copolyamides, having similar cycloaliphatic monomer contents, can be understood.SCOPUS: cp.jFLWINinfo:eu-repo/semantics/publishe