This manuscript presents data related to the research article entitled “Synthesis and characterization of sustainable polyurethane foams based on polyhydroxyls with different terminal groups” (DOI: ...10.1016/j.polymer.2018.06.077) 1. We provide Supplementary data on the chemical properties, in terms of FTIR characterization, of polyhydroxyls produced starting from bio-based feedstock (biosuccinic acid and 1,4 butandiol) and thermal properties (glass transition temperature-Tg and thermal degradation behavior) of polyurethane and copolymer urethane-amide foams manufactured from the aforementioned polyhydroxyls. The FTIR characterization elucidates the chemical structure of polyhydroxyls and allows to make some hypothesis on their reaction routes with the isocyanate molecules. The thermal characterization revealed that the addition of bio-based polyhydroxyls to the sample formulations improves both the glass transition and degradation temperature of the foams. These foamed products exhibit potential performances to be applied as a substitute for conventional polyurethane foams.
In the present study, the superplasticizing effect of HASE (Hydrophobic Alkali Swellable Emulsions) associative polymers on a cementitious formulation has been studied through a Design of Experiment ...(DoE) statistical approach. The main advantage of a study based on a DoE approach is that it gives the possibility of carrying out tests in which there is a combination of the parameters chosen on two extremes. Thus, the tests are driven by a combination of these parameters according to the design.
The DoE approach was used to optimize the combination of HASE polymer synthesis reaction variables. As a final response from the design, or rather as an objective of our synthesis, the superplasticizing effect that each polymer has on the final diameter variation of the cementitious formulation after the Flow Table Test was chosen. The variation of the final diameter was considered as the difference with respect to the same formulation without the addition of the superplasticizer.
The variables were chosen in such a way as to have the greatest impact on the reaction product, in particular the quantity of acidic methacrylic monomer (MMA), quantity of surfactant (SDS), quantity of free radical initiator (ASP) and reaction time (t). These variables were assumed to be independent variables. The design also included a central level, that is an experiment in which all the factors are set at an intermediate value between the minimum and the maximum. In this case, only one central level was added for a total of 17 experiments. By applying the DoE design it was possible to identify that the variable that has the greatest influence on the final response, that is the diameter of the cementitious formulation after the Flow Table Test, is the variable linked to the concentration of the initiator (ASP). The other variables showed a lesser influence on the final response.
Biodiesel can be easily obtained starting from high-quality or refined vegetable oils and performing on these feedstocks a transesterification reaction usually promoted by alkaline catalysts in the ...homogeneous phase. In this production scheme the employment of low-quality or waste raw materials, as cheap as possible, must be carefully considered to strongly improve the economic competitiveness of this biofuel with respect to the petroleum-derived diesel. In the case of raw materials characterized by a high content of free fatty acids (FFAs), a preliminary esterification treatment with methanol or ethanol is necessary for the abatement of the FFA concentration below the threshold limit value of 0.5−1.0% by weight that is tolerable by the subsequent process step of alkaline transesterification. In the present work the esterification reaction in tubular packed bed reactors, operating under pressure and using a sulfonic acid resin as catalyst, has been extensively studied. As it is well-known, sulfonic exchange resins are subjected to an impressive swelling phenomenon, and it is difficult to obtain, in this case, a dimensionally stable packed bed reactor. A particular solution to this problem has been proposed by the authors using springs of suitable size and shape as catalyst diluent. The influence of operative conditions like overall feed flow rate, reactants feed molar ratio, reactor aspect ratio L/D R, and mixture viscosity in the described reactors has been investigated. The collected experimental data have been interpreted by means of a mono-dimensional packed bed reactor model in which the external mass-transfer limitation (fluid-to-particle) has been accounted for.
In the present paper, an alternative synthetic way to obtain chlorohydrins, that are commercial products from glycerol feedstock, is presented. This synthetic route to transform glycerol into these ...high-value chemicals involves the use of gaseous HCl and glycerol in the presence of a carboxylic acid, as catalyst, in order to obtain, as main product, αγ-dichlorohydrin. Monochlorohydrins are also obtained as intermediates reaction products. As shown in a previous work some catalysts are selective in the production of the desired product, while others give monochlorohydrins as the main products. We attempted to correlate the selectivity shown by different carboxylic acids to their pK a, but this correlation seems not of general validity and it still remains a problem to correlate the catalytic behavior with the molecular structure of the catalyst. At this purpose, in this work we have investigated the behavior of a homologous chlorinated series of catalysts, such as the following: acetic, monochloroacetic, dichloroacetic, and trichloroacetic acid, focusing in particular the attention on both activity and selectivity shown by each catalyst. A kinetic model, based on a reliable mechanism, developed in a previous work but implemented for the HCl gas–liquid partition has been used for interpreting all the kinetic runs. Then, the obtained kinetic constants have been elaborated by using the Taft equation in the attempt to correlate chemical structure of the catalyst and the activity.
The growing availability of glycerol, as a consequence of the increase in biodiesel production (for which glycerol is a byproduct), is rapidly saturating the market, and consequently, a great ...interest is now addressed to the development of new process routes for alternative uses of glycerol. Among the various possibilities, our attention has been focused on the glycerol chlorination reaction, with the aim to produce α,γ-dichlorohydrin. This compound can then subsequently be converted into epichlorohydrin, which is an important intermediate in the production of epoxy resins. α,γ-dicholorhydrin, together with α,β-dichlorohydrin, is currently synthesized starting from propylene via allyl chloride. In the present paper, the kinetics of glycerol chlorination with gaseous hydrochloric acid, for the production of α,γ-dichlorohydrin, has been investigated by means of a jacketed glass reactor operated in batch conditions for the substrate (glycerol) and continuously for the hydrochloric acid. Different organic acids have been tested as catalysts with good performances in terms of both activity and, in particular, selectivity toward the desired 1,3-dichlorinated product. A reaction mechanism has been proposed and a consequent kinetic model has been developed in order to quantitatively describe the experimental data collected at various temperatures (80−120 °C), and the kinetic parameters have been evaluated. A generally good agreement between the experimental data and the theoretical model has been found.
In this paper, we have studied the KOH catalyzed transesterification reaction of vegetable oil with methanol in a tubular reactor filled with small spheres of stainless steel of different sizes. ...Three different packed bed configurations have been tested corresponding to different fluid dynamic situations. The first configuration corresponds to the tubular reactor filled with spheres of 2.5
mm of diameters; in the second configuration an opportune amount of spheres of 1
mm has been added to the mentioned spheres of 2.5
mm for filling the void volume of the octahedral cavities between the bigger spheres; in the third configuration an opportune amount of spheres of 0.39
mm has been added to spheres of 2.5
mm for filling the void volume of the tetrahedral cavities between the bigger spheres. The three mentioned configurations give place to the formation of micro-channels with an approximated size of respectively 1000
μm, 500
μm and 300
μm. These systems, subjected to fluid dynamic characterization, have shown a very high local turbulence (static mixer), in particular, when a packed bed reactor with dual size packing is used. Then, kinetic transesterification runs have been made by using the three mentioned packed bed reactors and a very high productivity has been obtained as a consequence of the induced local micro-mixing. A simplified kinetic model has been developed, which is able to describe many runs in batch conditions reported by the literature. This model resulted unsuitable to simulate the continuous runs performed in the described packed bed reactors. Our conclusion is that monophasic models, often proposed in the literature, are not able to describe the kinetic behavior of KOH catalysed transesterification in microchannels devices. At last, the described microchannels device represents, as it will be discussed, an ideal connection between a traditional tubular packed bed reactor and the recently appeared microreactors that are very efficient in mass and energy transfer operations for process intensification.
The molecular structure characterization of butyl and bromobutyl rubber (BIIR) requires the definition of three main parameters: (I) the unsaturation degree of the rubbers, (II) the total bromine ...content of the BIIRs, and (III) the functional bromine content of the BIIRs. The analytical methods for the determination of the previously mentioned parameters have been described and critically examined in this review.
In the present work, a new laboratory device specifically developed to obtain microchannels to test the process intensification effects on a suitable test reaction will be described. Ideally, this ...device represents a connection between a traditional tubular packed-bed reactor and the recently appeared microreactors that are very efficient, as it is well-known, in mass- and energy-transfer operations. To test the performance of this microreactor, the decomposition of hydrogen peroxide (H2O2) has been chosen as a test reaction. This reaction is of great industrial interest, because many processes use H2O2 as an oxidizing agent and the decomposition of the excess is normally performed under batch conditions by creating an alkaline medium. We observed that the H2O2 decomposition can also be promoted by stainless steel acting as a catalyst. Therefore, the decomposition of H2O2 is particularly enhanced in our device that is characterized by a relatively high surface area of stainless steel per unit of packing volume. Consequently, its result is particularly efficient in the chosen reaction. Experimental runs for H2O2 decomposition have been performed preliminarily under batch conditions, both in the homogeneous phase and in the presence of a known amount of metallic surface area as a catalyst, in the temperature range of 65−85 °C, to collect kinetic data. Successively, continuous runs at different temperatures (50−65 °C) and pH have been performed in the microchannel device, obtaining good performances and maintaining safety conditions. The obtained results have been interpreted and successfully simulated in a simplified way.
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