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ChatGPT is an AI language model trained on vast amounts of text data, including scientific papers, providing a comprehensive understanding of catalysis. However, its reliability in catalysis research is unknown. To evaluate reliability, we compared a ChatGPT-generated review article on heterogeneous catalysts for higher alcohols synthesis by CO2 hydrogenation to published peer-reviewed papers. Although the ChatGPT review article covers most necessary parts, it lacks sufficient discussion of the reaction mechanism. The core sections are too general, being not specific enough to the topic, and contain errors. The lack of citations further increases unreliability. While ChatGPT can provide much content on catalysis, it is insufficient and inaccurate for research on specific topics.

The present invention relates to a polyalkylene carbonate, preferably PRC, and the use thereof in packaging, in coating surfaces, in cosmetics, in the biomedical or textile sector or to produce composite materials or moisture absorption devices. Preferably, said polyalkylene carbonate is obtained by reacting CO2 with an alkyl epoxide preferably containing at least 3 atoms of carbon, preferably propylene oxide, in the presence of a zinc dicarboxylate catalyst; said catalyst being obtained by reacting, with a preferably saturated aliphatic dicarboxylic acid, a zinc-based compound comprising a mixture of ZnO and a compound having the general formula (I): Znx(0H)y(L)z-nH2 O (I) wherein L is selected in the group consisting of: NO3, CH3CO2, (SO4)0.5, halide, and acetyl acetonate (AcAc), 2x = y + z; wherein x is comprised between 1 and 5, y is comprised between 1 and 8, z is comprised between 1 and 2, and n is comprised between 0 and 20.

The present invention relates to a process for the synthesis of a zinc-based compound having general formula (I): wherein L is selected in the group consisting of: NO3, CH3CO2, (SO4)0.5, halide, and acetyl acetonate (AcAc), 2x = y + z; wherein x is comprised between 1 and 5, y is comprised between 1 and 8, z is comprised between 1 and 2, and n is comprised between 0 and 20. Said zinc-based compound is then used for the synthesis of a zinc dicarboxylate catalyst to be used for the heterogeneous catalytic copolymerization of a polyalkylene carbonate starting from CO2 and an alkyl epoxide, preferably containing at least 3 atoms of carbon, said polyalkylene carbonate being characterised by chemical-physical and mechanical properties which make it advantageous for a variety of different applications.

The production of nitrous oxide, N

Bimetallic zeolite Beta in bead format and containing Al sites with Brønsted acid behavior and Sn, Zr or Hf sites with Lewis acid character, were prepared using a two-step synthetic route. First, zeolite Beta in the format of macroscopic beads (400 to 840 μm) with hierarchical porosity (micropores accessed through meso- and macropores in the range of 30 to 150 nm) were synthesized by hydrothermal crystallization in the presence of anion-exchange resin beads as hard template and further converted into their H-form. Next, the zeolite beads were partially dealuminated using different concentrations of HNO3 (i.e., 1.8 or 7.2 M), followed by grafting with one of the above-mentioned metals (Sn, Zr or Hf) to introduce Lewis acid sites. These bimetallic zeolites were tested as heterogeneous catalysts in the conversion of dihydroxyacetone (DHA) to methyl lactate (ML). The Sn-containing zeolite Beta beads treated by 1.8 M HNO3 and grafted with 27 mmol of SnCl4 (Sn-deAl-1.8-Beta-B) demonstrated the best catalytic activity among the prepared bimetallic zeolite beads, with 99% selectivity and 90% yield of ML after 6 h at 90 °C. This catalyst was also tested in combination with Au-Pd nanoparticles supported on functionalized carbon nanotubes (CNTs) as multifunctional catalytic system for the conversion of glycerol to ML, achieving 29% conversion of glycerol and 67% selectivity towards ML after 4.5 h at 140 °C under 30 bar air. The catalytic results were rationalized by means of a thorough characterization of the zeolitic beads with a combination of techniques (XRD, N2-physisorption, SEM, XRF, TEM, UV-vis spectroscopy and pyridine-FT-IR).

A series of heterogeneous catalysts consisting of highly dispersed Pt nanoparticles supported on nanosized ZrO2 (20 to 60 nm) was synthesized and investigated for the one-pot transfer hydrogenation between glycerol and cyclohexene to produce lactic acid and cyclohexane, without any additional H-2. Different preparation methods were screened, by varying the calcination and reduction procedures with the purpose of optimizing the dispersion of Pt species (i.e., as single-atom sites or extra-fine Pt nanoparticles) on the ZrO2 support. The Pt/ZrO2 catalysts were characterized by means of transmission electron microscopy techniques (HAADF-STEM, TEM), elemental analysis (ICP-OES, EDX mapping), N-2-physisorption, H-2 temperature-programmed-reduction (H-2-TPR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Based on this combination of techniques it was possible to correlate the temperature of the calcination and reduction treatments with the nature of the Pt species. The best catalyst consisted of subnanometer Pt clusters (

A new, sustainable catalytic route for the synthesis of tetrahydrofuran-2,5-dicarboxylic acid (THFDCA), a compound with potential application in polymer industry, is presented starting from the bio-based platform chemical 5-(hydroxymethyl)furfural (HMF). This conversion was successfully achieved via oxidation of tetrahydrofuran-2,5-dimethanol (THFDM) over hydrotalcite (HT)-supported gold nano-particle catalysts (similar to 2 wt %) in water. THFDM was readily obtained with high yield (>99%) from HMF at a demonstrated 20 g scale by catalytic hydrogenation. The highest yield of THFDCA (91%) was achieved after 7 h at 110 degrees C under 30 bar air pressure and without addition of a homogeneous base. Additionally, Au-Cu bimetallic catalysts supported on HT were prepared and showed enhanced activity at lower temperature compared to the monometallic gold catalysts. In addition to THFDCA, the intermediate oxidation product with one alcohol and one carboxylic acid group (5-hydroxymethyl tetrahydrofuran-2-carboxylic acid, THFCA) was identified and isolated from the reactions. Further investigations indicated that the gold nanoparticle size and basicity of HT supports significantly influence the performance of the catalyst and that sintering of gold nanoparticles was the main pathway for catalyst deactivation. Operation in a continuous setup using one of the Au-Cu catalysts revealed that product adsorption and deposition also contributes to a decrease in catalyst performance.

High-surface area Nb2O5 nanoparticles were synthesised by a novel supercritical-CO2-assisted method (Nb2O5-scCO2) and were applied for the first time as a heterogeneous catalyst in the oxidative coupling of aniline to azoxybenzene using the environmentally friendly H2O2 as the oxidant. The application of scCO2 in the synthesis of Nb2O5-scCO2 catalyst resulted in a significantly enhanced catalytic activity compared to a reference catalyst prepared without scCO2 (Nb2O5-Ref) or to commercial Nb2O5. Importantly, the Nb2O5-scCO2 catalyst achieved an aniline conversion of 86% (stoichiometric maximum of 93% with the employed aniline-to-H2O2 ratio of 1 : 1.4) with an azoxybenzene selectivity of 92% and with 95% efficiency in H2O2 utilisation in 45 min without requiring external heating (the reaction is exothermic) and with an extremely low catalyst loading (weight ratio between the catalyst and substrate, Rc/s = 0.005). This performance largely surpasses that of any other heterogeneous catalyst previously reported for this reaction. Additionally, the Nb2O5 catalyst displayed high activity also for substituted anilines (e.g. methyl or ethyl-anilines and para-anisidine) and was reused in consecutive runs without any loss of activity. Characterisation by means of N2-physisorption, XRD, FTIR and TEM allowed the correlation of the remarkable catalytic performance of Nb2O5-scCO2 to its higher surface area and discrete nanoparticle morphology compared to the aggregated larger particles constituting the material prepared without scCO2. A catalytic test in the presence of a radical scavenger proved that the reaction follows a radical pathway.

Base-free, multifunctional heterogenous catalytic systems for the highly efficient conversion of glycerol into methyl lactate. Multifunctional catalytic systems consisting of physical mixtures of (i) bimetallic Au–Pd nanoparticles (average size of 3–5 nm) supported on functionalised carbon nanotubes (CNTs) and (ii) Sn-MCM-41 nanoparticles (50–120 nm), were synthesised and investigated for the base-free, selective conversion of glycerol to methyl lactate in a batch reactor. The catalysts were characterised by means of transmission electron microscopy, N 2 -physisorption, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and by Boehm titration. The catalyst based on bimetallic AuPd/CNTs showed much higher activity than the monometallic Au or Pd counterparts, thus indicating synergetic effects. Functionalisation of the CNTs by oxidative treatments had a positive effect on catalyst performance, which was correlated to the observed increase in surface acidity and hydrophilicity. The highest yield of methyl lactate achieved in this work was 85% at 96% glycerol conversion (140 °C, 10 h at 30 bar air), which is the highest yield ever reported in the literature so far. Insights in the reaction pathway were obtained by monitoring the conversion-time profiles for intermediates and their possible role as inhibitors. Batch recycling experiments demonstrated the excellent reusability of the catalyst.

A catalyst screening study is reported on the liquefaction of humins, the solid byproducts from C6 sugar biorefineries for levulinic acid and 5-hydroxymethylfurfural production. Experiments were carried out in a batch reactor using an artificial model of humin derived from glucose with isopropanol (IPA) as the solvent at 400 degrees C for a 3 h batchtime. Initial studies using noble metal catalysts (Rh, Pt, Pd, Ru) on a carbon support revealed that Pt was the best catalyst in terms of humin conversion (77%) and amounts of alkylphenolics and aromatics in the product oil (GCxGC-FID). Subsequent support screening studies (TiO2, ZrO2, CeO2) were performed using Pt as the active metal and the results were compared with Pt/C. Detailed liquid product analysis (GPC, GC-MS, GCxGC) including blank reactions in the absence of humins revealed that the humins are mainly converted to monomeric alkylphenolics and aromatics oligomers (GPC) and (GC). IPA was shown not to be inert and is converted to acetone and hydrogen, and the latter is the hydrogen source for the various metal catalysed hydrogenolysis and hydro(deoxy) genation reactions. In addition, acetone is converted to aldolcondensation products (like methylisobutylketone, MIBK) and hydrogenation products derived thereof. The best results were obtained with Pt/C when considering humin conversion. However, Pt/CeO2 was shown to be more attractive when considering the amounts of alkylphenolics in the product oils (20.4 wt% based on humin intake).

Bimetallic Ni-Co catalysts supported on nanosized CeO2 were prepared and investigated as heterogeneous catalysts for the transfer hydrogenation between glycerol and various H2 acceptors (levulinic acid, benzene, nitrobenzene, 1-decene, cyclohexene) to selectively produce lactic acid (salt) and the target hydrogenated compound. The bimetallic NiCo/CeO2 catalyst showed much higher activity than the monometallic Ni or Co counterparts (with equal total metal mass), thus indicating strong synergetic effects. The interaction between the metallic sites and the CeO2 support was thoroughly characterised by means of transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDX) mapping, X-ray photoelectron spectroscopy (XPS), hydrogen-temperature programmed reduction (H2-TPR) and X-ray diffraction (XRD). Combining characterisation and catalytic results proved that the Ni species are intrinsically more active than Co species, but that incorporating Co into the catalyst formulation prevented the formation of large Ni particles and led to highly dispersed metal nanoparticles on CeO2, thus leading to the observed enhanced activity for the bimetallic system. The highest yield of lactic acid (salt) achieved in this work was 93% at 97% glycerol conversion (160 °C, 6.5 h at 20 bar N2, NaOH: glycerol = 1.5). The NiCo/CeO2 catalyst also exhibited high activity and selectivity towards the target hydrogenated products in the transfer hydrogenation reactions between glycerol and various H2 acceptors. Batch recycle experiments showed good reusability, with retention of 80% of the original activity after 5 runs.

Multifunctional catalytic systems consisting of physical mixtures of Au nanoparticles (2-3 nm) supported on metal oxides and Sn-MCM-41 nanoparticles (50-120 nm) were synthesized and investigated for the selective conversion of glycerol to methyl lactate. The Au catalyst promotes the oxidation of glycerol to trioses, whereas the solid acid Sn-MCM-41 catalyzes the rearrangement of the intermediate trioses to methyl lactate. Among the supported Au nanoparticles, Au/CuO led to the highest yield and selectivity toward methyl lactate, while the Sn-MCM-41 nanoparticles showed much better catalytic performance than a benchmark solid acid catalyst (USY zeolite). The activity of the multifunctional catalytic system was further optimized by tuning the calcination temperature, the gold loading in the Au/CuO catalyst, and the Au/Sn molar ratio, reaching 63% yield of methyl lactate (ML) at 95% glycerol conversion. This catalytic system also showed excellent reusability. The catalytic results were rationalized on the basis of a detailed characterization by means of TEM, N2-physisorption, UV-vis spectroscopy, and by FT-IR using probe molecules (CO and ethanol).

gamma-Valerolactone (GVL) has been identified as a sustainable platform chemical for the production of carbon-based chemicals. We here report an experimental study on the catalytic hydrogenation of levulinic acid (LA) in water to GVL in a packed bed reactor using supported Ru catalysts (carbon, alumina, and titania) with particle sizes in the millimeter range (C-LA,C-0 = 1.2 mol/L, LA feed = 1 mL/min, H-2 feed = 30 mL/min, 90 degrees C, 45 bar, and WHSV = 30 of g(feed)/g(cat).h). Intraparticle diffusion limitations for hydrogen and LA were confirmed by performing LA hydrogenation experiments with different catalyst particle sizes (0.5 wt % Ru/C) and supported by calculations. The best performance was obtained with Ru/C, showing high LA conversion during 6 h on stream with negligible deactivation. Ru/Al2O3 was found to be less active, and stability was also considerably reduced due to the reactivity of the support. Ru/TiO2 was considerably less reactive, though stability was better than that for the alumina based counterpart. A long duration test (52 h) for Ru/C (0.5 wt % of Ru) showed a small though significant reduction in LA conversion (from 95 to 82 mol %). Catalyst characterization studies showed a significant decrease in the specific surface area of the catalyst (from 1110 m(2)/g to 390 m(2)/g) and sintering of the Ru particles (TEM-HAADF).

Hence, it is the only relatively inexpensive diol which is based on renewable resources and is not based on oil or coal chemistry. Currently, isosorbide is produced by heating of D-sorbitol under vacuum and in the presence of an acidic catalyst to result in a stepwise cyclization with elimination of water. Examples of acid catalysts used commercially include mineral acids such as H

La-modified NaY zeolites have been prepared through impregnation and in situ synthesis methods. The surface structure of the obtained zeolites was then characterised by XRD, UV–Vis DRS, FT-Far-IR, Raman spectra, H2-TPR, N2 adsorption, and NH3-TPD. The results of the catalytic dehydration reaction of lactic acid showed that the La/NaY catalyst prepared by impregnation method exhibited higher selectivity to acrylic acid than the La–NaY prepared by the in situ synthesis. The characterisation results indicated that the enhanced catalytic performance could be attributed to the difference of La3+ ion location caused by the different preparation protocols, which would influence the electric field distribution of zeolites cages, the reactant adsorption, chemical activation, and the reaction path. Les zeolithes NaY modifiees avec du lanthane (La) ont ete preparees grâce a des methodes d'impregnation et de synthese in situ. La structure de la surface des zeolithes ainsi obtenues a ete ensuite caracterisee par DRX, spectrophotometre UV–VIS DR, FT-Far-IR, spectroscopie Raman, reduction thermo-programmee de H2, adsorption de N2 et desorption thermo-programmee de NH3. Les resultats de la reaction de deshydratation catalytique de l'acide lactique montrent que le catalyseur La/NAY prepare grâce a la methode d'impregnation a fait preuve d'une plus grande selectivite a l'acide acrylique que le catalyseur La/NAY prepare grâce a la synthese in situ. Les resultats de caracterisation indiquent que le meilleur rendement catalytique peut etre du aux differences d'emplacement de l'ion La3+ causees par les differents protocoles de preparation, qui peuvent influer sur la distribution du champ electrique des cages de zeolithes, l'adsorption du reactif, l'activation chimique et le chemin reactionnel. Can. J. Chem. Eng. © 2010 Canadian Society for Chemical Engineering

The transformation of cellulose or cellulose-derived carbohydrates into platform chemicals is the key to establish biomass-based sustainable chemical processes. The systems able to catalyze the conversion of cellulose into key chemicals in water without the consumption of hydrogen are limited. We report that simple vanadyl (VO(2+)) cations catalyze the conversions of cellulose and its monomer, glucose, into lactic acid and formic acid in water. We have discovered an interesting shift of the major product from formic acid to lactic acid on switching the reaction atmosphere from oxygen to nitrogen. Our studies suggest that VO(2+) catalyzes the isomerization of glucose to fructose, the retro-aldol fragmentation of fructose to two trioses, and the isomerization of trioses, which leads to the formation of lactic acid under anaerobic conditions. The oxidative cleavage of C-C bonds in the intermediates caused by the redox conversion of VO2(+)/VO(2+) under aerobic conditions results in formic acid and CO2. We demonstrate that the addition of an alcohol suppresses the formation of CO2 and enhances the formic acid yield significantly to 70-75 %.

The direct transformation of cellulose, which is the main component of lignocellulosic biomass, into building-block chemicals is the key to establishing biomass-based sustainable chemical processes. Only limited successes have been achieved for such transformations under mild conditions. Here we report the simple and efficient chemocatalytic conversion of cellulose in water in the presence of dilute lead(II) ions, into lactic acid, which is a high-value chemical used for the production of fine chemicals and biodegradable plastics. The lactic acid yield from microcrystalline cellulose and several lignocellulose-based raw biomasses is >60% at 463 K. Both theoretical and experimental studies suggest that lead(II) in combination with water catalyses a series of cascading steps for lactic acid formation, including the isomerization of glucose formed via the hydrolysis of cellulose into fructose, the selective cleavage of the C3-C4 bond of fructose to trioses and the selective conversion of trioses into lactic acid.

γ-Valerolactone (GVL) has been identified as a sustainable platform chemical for the production of carbon-based chemicals. Here we report a screening study on the hydrogenation of levulinic acid (LA) to GVL in water using a wide range of ruthenium supported catalysts in a batch set-up (1 wt. % Ru, 90 °C, 45 bar of H2, 2 wt. % catalyst on LA). Eight monometallic catalysts were tested on carbon based(C, carbon nanotubes (CNT)) and inorganic supports (Al2O3, SiO2, TiO2, ZrO2, Nb2O5 and Beta-12.5). The best result was found for Ru/Beta-12.5 with almost quantitative LA conversion (94%) and 66% of GVL yield after 2 h reaction. The remaining product was 4-hydroxypentanoic acid (4-HPA). Catalytic activity for a bimetallic RuPd/TiO2 catalyst was by far lower than for the monometallic Ru catalyst (9% conversion after 2 h). The effects of relevant catalyst properties (average Ru nanoparticle size, Brunauer-Emmett-Teller (BET) surface area, micropore area and total acidity) on catalyst activity were assessed.