C:Corrosive;
79-10-7Relevant articles and documents
Acetylene carbonylation over Ni-containing catalysts: Role of surface structure and active site distribution
Xie, Hao,Lin, Tiejun,Shi, Li,Meng, Xuan
, p. 97285 - 97292 (2016)
Heterogenization of homogeneous catalyst for acetylene carbonylation was carried out by preparing a series of Ni-modified catalysts (Ni-ZSM-5, Ni-IM-5 and Ni-MCM-41). Several important properties of the heterogeneous catalysts were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES), XPS, XRD, N2 adsorption, pyridine-FTIR, SEM and TGA. Moreover, we used various activity criteria to dissipate perturbing factors, when we focused on the influence of surface structure and active site distribution. The result that Ni-IM-5 had the greatest TOFNi = 5107 g acrylic acid per g Ni per h showed that the surface structure of samples did not influence the catalyst performance significantly. In addition, the highest ratio of nickel sites/acid sites in Ni-MCM-41 represented the best active site distribution. Thus, Ni-MCM-41 has the highest TOFcat = 70.6 g acrylic acid per g cat. per h. Furthermore, stability testing of the catalysts showed the Ni-MCM-41 could be used four times, while others only twice.
Ni-exchanged Y-zeolite: An efficient heterogeneous catalyst for acetylene hydrocarboxylation
Lin, Tie Jun,Meng, Xuan,Shi, Li
, p. 163 - 171 (2014)
A series of Ni-modified Y-zeolites with varying Ni loading in the presence of cupric salt as promoter were studied for acetylene hydrocarboxylation performed in a batch reactor. The catalysts were characterized by elemental analysis, H2-TPR, XRD, NH3-TPD, pyridine-FTIR, SEM, TG-DTG and Raman. It was found that the catalytic activity showed a pronounced dependence on the supports, metal introduction method, promoters and reaction conditions. The nickel species present as charge compensation cations in the zeolite framework constitute the active sites, and the acid sites help to promote the performance of carbonylation. Moreover, two types of coke were observed, and the remarkable reusability of NiY is attributable to the location of the coke outside the zeolite crystals. High catalytic performance was obtained over a NiY(7.0) catalyst with 62 gacrylic acid/(g cat. · h) of yield at 235 °C, 3.6 MPa of initial total pressure and 0.8 mM/l of cupric bromide within 40 min of reaction time. This is the most effective heterogeneous system for synthesizing acrylic acid by carbonylation of acetylene to date.
COMPETITION BETWEEN DECARBOXYLATION AND ISOMERIZATION IN THE C3H5O2(1+) ENERGY SURFACE. JUSTIFICATION OF THE EXPERIMENTAL RESULTS BY MOLECULAR ORBITAL CALCULATIONS ON THE SOLVATED IONS
Rajadell, Fernando,Planelles, Josep,Tomas, Francisco,Asensio, Gregorio,Miranda, Miguel A.,Sabater, Maria J.
, p. 221 - 226 (1994)
In contrast with recent molecular orbital calculations on the decarboxylation of O-protonated 2-oxetanone, this experimental work indicates that no decarboxylation of this cation occurs in sulphuric acid solution up to 150 deg C, but instead a clean isomerization to protonated acrylic acid takes place.Parallel theoretical work shows that the gas-phase model is too crude to account successfully for the experimental facts obtained in acidic media.However, the latter are well reproduced when the effect of the solvent is taken into account.The present findings do not necessarily invalidate the reaction mechanism currently accepted to explain the rate enhancement and change of stereochemistry accompanying the decarboxylation of 3,4-disubstituted 2-oxetanones under acid catalysis.
How important is the (001) plane of M1 for selective oxidation of propane to acrylic acid?
Celaya Sanfiz,Hansen,Sakthivel,Trunschke,Schloegl,Knoester,Brongersma,Looi,Hamid
, p. 35 - 43 (2008)
The role of the (001) crystallographic plane of the M1 phase of MoVTeNb mixed-oxide catalysts in selective oxidation of propane to acrylic acid was addressed by investigating a phase-pure M1 material preferentially exposing this surface. A model catalyst was prepared by complete silylation of M1, followed by breakage of the SiO2-covered needles. Using this approach, the reactivity of the M1 (001) surface was investigated by combining a microreactor study of propane oxidation with high-sensitivity low-energy ion scattering (HS-LEIS). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to study the shape and microstructure of the model system and verify the surface exposure of the model catalyst. The specific rate of formation of acrylic acid on the model catalyst was found to be similar to that on the phase-pure M1 reference material, indicating that the (001) plane of the M1 crystal structure did not have better catalytic properties compared with the lateral surface of M1 needles in propane oxidation.
Pd@Zn-MOF-74: Restricting a Guest Molecule by the Open-Metal Site in a Metal-Organic Framework for Selective Semihydrogenation
Wu, Hui Qiong,Huang, Ling,Li, Jian Qiang,Zheng, An Min,Tao, Yuan,Yang, Li Xiao,Yin, Wen Hui,Luo, Feng
, p. 12444 - 12447 (2018)
In this work, we found that the open-metal site in a metal-organic framework (MOF) can be used to enhance such selectivity. Hydrogenation of phenylacetylene over such a catalyst enables ultrahigh styrene selectivity of 92% at full conversion with a turnover frequency of 98.1 h-1. The origin of ultrahigh selectivity, as unveiled by density functional theory calculation, is due to a coordination interaction between the open Zn(II) site and the C≡C bond of phenylacetylene.
Immobilization of rhodococcus AJ270 and use of entrapped biocatalyst for the production of acrylic acid
Colby, John,Snell, David,Black, Gary W.
, p. 655 - 666 (2000)
Rhodococcus AJ270 is adsorbed by Dowex 1 at 15.4 mg dry weight per g resin with maximum amidase specific activity observed at lower loadings. Bacteria form a monolayer on the resin surface, and adsorption is complete within 2 min. AJ270 can be entrapped in agar and agarose gels (optimum loading: 20 mg dry weight bacteria per cm3 gel). Adsorption and entrapment improve amidase thermal stability 3-4 fold, and entrapment shifts the pH optimum from 8 to 7. Adsorbed and free bacteria show similar values for Km and Vmax, but entrapped bacteria have higher Km values. Compared with bacteria adsorbed to Dowex, the activity per cm3 of matrix of agar-entrapped AJ270 is eight-fold higher. In stirred-tank reactors, exposure to acrylic acid reduces the amidase activity of the biocatalyst in the hydrolysis of acrylamide. In column reactors, entrapped AJ270 suffers little reduction in amidase activity against 0.25 M acrylamide over 22 h continuous operation.
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Riiber,Schetelig
, p. 349 (1904)
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Enhancement of acrylic acid yields in propane and propylene oxidation by selective P Doping of MoV(Nb)TeO-based M1 and M2 catalysts
Grasselli,Lugmair,Volpe Jr.,Andersson,Burrington
, p. 33 - 38 (2010)
The selective doping of M1 and M2 phases for the selective oxidation of propane and propylene to acrylic acid (AA) was investigated. A series of catalytic materials for the oxidation of propane were prepared with the general precursor composition Mo1V0.31-Te0.37Nb xPyOn. A first solution was prepared by dissolving ammonium heptamolybdate, ammonium vanadate, and telluric acid in water at 60°C. This solution was allowed to cool to room temperature. A second solution was prepared by dissolving niobic acid in oxalic acid at 60°C. The appropriate amount of the first solution, second solution, and phosphoric acid were mixed and then dried by rotary evaporation. Each catalyst was tested at four different space velocities, starting with the highest, at several reaction temperatures starting at the lowest temperature. Doping of crystalline M1 and M2 phases with P in selective oxidation of propane or propylene enhances significantly the desired AA yields at commercially relevant high hydrocarbon conversions.
V-Zr-P oxide catalysts for highly selective oxidation of propane to acrylic acid
Han, Yi-Fan,Wang, Huai-Ming,Cheng, Hua,Deng, Jing-Fa
, p. 521 - 522 (1999)
V-Zr-P oxide catalysts have been prepared and exhibited high selectivity in the oxidation of propane to acrylic acid.
Oxidation of Propane to Acrylic Acid on V2O5-P2O5-based Catalysts
Ai, Mamoru
, p. 786 - 787 (1986)
V2O5-P2O5-based oxides, especially V2O5-P2O5-TeO2, are effective catalysts for the partial oxidation of propane to acrylic acid using gaseous oxygen as an oxidant; a yield of 9 molpercent was reached.
Hydrothermal synthesis of Mo-V mixed oxides possessing several crystalline phases and their performance in the catalytic oxydehydration of glycerol to acrylic acid
Rasteiro, Letícia F.,Vieira, Luiz H.,Possato, Luiz G.,Pulcinelli, Sandra H.,Santilli, Celso V.,Martins, Leandro
, p. 10 - 18 (2017)
The one-step oxydehydration of glycerol to acrylic acid over molybdenum and vanadium mixed oxides was investigated. The Mo-V oxide catalysts were prepared by a simple hydrothermal method under different synthesis and calcination atmospheres and were characterized by in situ XRD, TPD-NH3, N2 adsorption/desorption, X-ray absorption near vanadium K-edge spectroscopy and thermogravimetry. The catalytic performance of the samples at different temperatures (290, 320 and 350 °C) and under different gas flow compositions (20% O2 in N2, 100% O2, or 100% N2) revealed that the arrangement of the crystallographic structures of the active phases directly influenced the catalytic performance. It was found that the catalysts heat-treated in oxidizing atmosphere gave superior catalytic results comparing with the catalysts heat-treated in inert atmosphere due to the equilibrium between the crystalline phases MoVO5 and Mo4.65V0.35O14 that contains V+4 and V+5. Catalytic oxydehydration at 320 °C under a flow of 100% O2 gave the best performance, achieving selectivity of 33.5% towards acrylic acid and 100% conversion of glycerol.
Selective dehydrosulfurization of 3-mercaptopropionic acid to acrylic acid on silicalite catalyst
Pina, Cristina Della,Falletta, Ermelinda,Rossi, Michele
, p. 456 - 459 (2010)
Dehydrosulfurization of 3-mercaptopropionic acid has been investigated in a fixed bed reactor using a silicalite catalyst in order to recover the hydrocarbon core. Under reductive conditions, acrylic acid was formed in high yield at 350 °C and atmospheric pressure as the desired product along the toxic H2S, whereas, carrying out the reaction in the presence of air, safer dihydrogenpolysulfides resulted as the co-product.
Nickel oxide-silica core-shell catalyst for acetylene hydroxycarbonylation
Choi, Hong Sub,Park, Ji Hoon,Bae, Jong Wook,Lee, Jin Hee,Chang, Tae Sun
, p. 86 - 90 (2019)
Acrylic acid and its ester derivatives are important chemicals utilized to synthesize numerous end products. Acrylic acid is industrially produced via propylene oxidation. We report in this study a nickel oxide-silica core-shell catalyst (NiO@SiO2) for acetylene hydroxycarbonylation as an alternative way to synthesize acrylic acid. NiO@SiO2 catalyst provided the higher turnover frequency and yield than commercial nickel oxide catalyst on acetylene hydroxycarbonylation. The carbon monoxide/acetylene ratio influenced more significantly to initial reaction rate than final acrylic acid yield. The silica shell protected the nickel oxide from sintering during reaction, however, the catalyst was deactivated by coke formation, attributed to acetylene decomposition.
Parahydrogen-Induced Polarization Relayed via Proton Exchange
Them, Kolja,Ellermann, Frowin,Pravdivtsev, Andrey N.,Salnikov, Oleg G.,Skovpin, Ivan V.,Koptyug, Igor V.,Herges, Rainer,H?vener, Jan-Bernd
supporting information, p. 13694 - 13700 (2021/09/07)
The hyperpolarization of nuclear spins is a game-changing technology that enables hitherto inaccessible applications for magnetic resonance in chemistry and biomedicine. Despite significant advances and discoveries in the past, however, the quest to establish efficient and effective hyperpolarization methods continues. Here, we describe a new method that combines the advantages of direct parahydrogenation, high polarization (P), fast reaction, and low cost with the broad applicability of polarization transfer via proton exchange. We identified the system propargyl alcohol + pH2 → allyl alcohol to yield 1H polarization in excess of P ≈ 13% by using only 50% enriched pH2 at a pressure of ≈1 bar. The polarization was then successfully relayed via proton exchange from allyl alcohol to various target molecules. The polarizations of water and alcohols (as target molecules) approached P ≈ 1% even at high molar concentrations of 100 mM. Lactate, glucose, and pyruvic acid were also polarized, but to a lesser extent. Several potential improvements of the methodology are discussed. Thus, the parahydrogen-induced hyperpolarization relayed via proton exchange (PHIP-X) is a promising approach to polarize numerous molecules which participate in proton exchange and support new applications for magnetic resonance.
Cu(II)-Based Ionic Liquid Supported on SBA-15 Nanoparticles Catalyst for the Oxidation of Various Alcohols into Carboxylic Acids in the Presence of CO2
Chen, Yanwu,Hou, Dejian,Lin, Litian,Peng, Qi,Sadeghzadeh, Seyed Mohsen
, (2021/07/26)
In this paper, we have produced carboxylic acids by the oxidation of various alcohols in the presence of CO2 using SBA-15/IL supported Cu(II) (SBA-15/IL/Cu(II)) as nanocatalyst. The obtained products showed to have excellent yields by taking into account of SBA-15/IL/Cu(II) nanocatalyst. In addition, the analysis of EDX, SEM, TGA, TEM, XPS, and FT-IR showed the heterogeneous structure of SBA-15/IL/Cu (II) catalyst. It is determined that, after using SBA-15 excess, the catalytic stability of the system was enhanced. Moreover, hot filtration provided a full vision in the heterogeneous catalyst nature. The recycling as well as reuse of the catalyst were studied in cases of coupling reactions many times. Moreover, we have studied the mechanism of the coupling reactions. Graphic Abstract: [Figure not available: see fulltext.]
Mo–V–O nanocrystals synthesized in the confined space of a mesoporous carbon
Mukai, Shin R.,Obunai, Ryo,Ogino, Isao,Tamura, Keisuke,Ueda, Wataru
, (2021/08/21)
Ternary Mo–V oxide nanocrystals (Nano-MoVO) were hydrothermally synthesized in the confined space of a mesoporous carbon template and tested in the oxidative dehydrogenation (ODH) of ethane and propane. The synthesized nanocrystals are approximately 60 nm in length, 20 nm in diameter on average, and possess a structure resembling orthorhombic MoVO (Orth-MoVO) as indicated by spectroscopic and microscopy characterization. The Nano-MoVO catalyst has a 5-fold higher mesopore volume and a 4-fold larger external surface area than an Orth-MoVO synthesized by a conventional method (Orth-MoVO) as characterized through N2 adsorption analysis. Nano-MoVO shows similar activation energy in the ODH of ethane compared with other conventional MoVO catalysts. However, Nano-MoVO exhibits significantly higher propane/ethane activation rate ratio and higher propene selectivity even in the absence of elements such as Te and Nb that suppress overoxidation of propane-derived species to COx. The results suggest the benefits of the nanocrystalline morphology to limit overoxidation.
