- Selective oxidation of methacrolein to methacrylic acid on carbon catalysts
-
Different carbon structures (activated carbon, carbon nanotubes, graphene and graphite)were investigated for the replacement of heteropoly catalysts for the oxidation of methacrolein to methacrylic acid. Activated carbon showed the best catalytic performance with higher catalytic activity than molybdovanaphosphoric acid at lower temperatures. The catalytic performance of activated carbon was further improved by the addition of heteroatoms, such as P, B, N and S. The latter occupy the electrophilic oxygen functional groups thus preventing further oxidation of methacrylic acid and improving reaction selectivity. The best catalytic performance results were obtained on activated carbon with 10 wt% P, where methacrolein conversion, methacrylic acid selectivity and yield at 270 °C were 40.1, 70.8 and 30.3%, respectively. The results of the present work show a novel way to design non-metal catalysts for the selective oxidation of methacrolein to methacrylic acid.
- Zhou, Lilong,Sun, Ye,Li, Bin,Li, Zhengjie,Zhang, Zhikun,Yun, Jimmy,Liu, Runjing
-
-
Read Online
- Structure-activity relationships in the hydrolysis of acrylate and methacrylate esters by carboxylesterase in vitro
-
Acrylate esters are important chemicals in the plastics industry, whose toxicity is theorized to involve alkylation of critical cellular nucleophiles via the Michael addition. Carboxylesterase-mediated hydrolysis of acrylates may be a detoxification mechanism as the unsaturated acid produced is not electrophilic under physiological conditions. Using purified porcine liver carboxylesterase, the enzymatic hydrolysis of several acrylate eaters was characterized to determine K(m) and V(max) values for each ester. The K(m) (μM) and V(max) (nmol/min) values observed for ethyl acrylate were 134 ± 16 (S.D.) and 8.9 ± 2.0, respectively. While the K(m) for ethyl methacrylate was not significantly different, the V(max), 5.5 ± 2.5, was significantly lower compared with the corresponding value for ethyl acrylate. The K(m) and V(max) for butyl acrylate were 33.3 ± 8.5 μM and 1.49 ± 0.83 nmol/min, respectively, and the corresponding values for its α-methyl analog were not significantly different. The K(m) and V(max) for tetraethyleneglycol dimethacrylate were 39 ± 15 μM and 2.9 ± 1.0 nmol/min, respectively. The V(max) for ethyleneglycol dimethacrylate, 6.9 ± 2.4 nmol/min, was significantly higher than that of the larger bifunctional ester tetraethyleneglycol dimethacrylate, but the K(m) was not significantly different. These results indicate that α-methyl substitution appears to have a minor effect in the enzymatic hydrolysis of acrylates, and suggest that the relative toxicity of acrylates is not due to differences in carboxylesterase-mediated hydrolysis.
- McCarthy, Timothy J.,Witz, Gisela
-
-
Read Online
- Catalysis by Heteropoly Compounds. XVIII. Oxidation of Methacrylaldehyde over 12-Molybdophosphoric Acid and Its Alkali Salts
-
The reaction scheme for the methacrylaldehyde oxidation over heteropoly compounds proposed previously (M.Misono et al., Proc. 7th Intl.Congr.Catal., 1980) was confirmed by 18O tracer experiments using the Pulse-MS method (combination of pulse reactor/mass spectrometer).The occurrence of direct and rapid oxygen exchange between methacrylaldehyde and the polyanion of MxH3-xPMo12O40 (M=Na, Cs, x=0-3.15) was verified under the reaction conditions.The results also suggested that this reaction is catalyzed by Broensted acid sites of the catalysts via such intermediates as (I) and/or (II) in scheme 1.It was shown that the methacrylaldehyde oxidation is a surface-type reaction and the catalytic activity is controlled by the oxidizing ability of the catalyst surface.
- Mizuno, Noritaka,Watanabe, Tetsuji,Misono, Makoto
-
-
Read Online
- PARTIAL OXIDATION OF ISOBUTENE TO METHACRYLIC ACID ON V2O5 -P2O5 CATALYSTS.
-
The vapor-phase air oxidation of isobutene was studied with V//2O//5, V//2O//5-TiO//2, V//2O//5-MoO//3, V//2O//5-P//2O//5, V//2O//5-P//2O//5-TeO//2, and heteropoly compound catalysts, such as H//3PMo//1//2O//4//0, Cs//2HPMo//1//2O//4//0, H//5PMo//1//0V//2O//4//0, and Cs//2//. //5H//2//. //5PMo//1//0V//2O//4//0, in the presence of water vapor. On pure V//2O//5, the oxidation products were acetic acid and carbon oxides, plus small amounts of acetone and methacrylaldehyde. With the addition of TiO//2 to V//2O//5, the selectivity to acetic acid increased a little, but the formation of methacrylaldehyde disappeared. The addition of MoO//3 to V//2O//5 enhanced the formations of acetone and methacrylaldehyde, to a certain extent, but methacrylic acid was not obtained.
- Ai
-
-
Read Online
- Direct Oxidation of Isobutane in to Methacrylic Acid and Methacrolein over Cs2.5Ni0.08-substituted H3PMo12O40
-
Cs+, and Ni2+, Mn2+ or Fe3+ substitution for H+ in H3PMo12O40 greatly enhanced the catalytic activity for the title reaction and among the catalysts tested Cs2.5Ni0.08H0.34PMo12O40 gave the highest yield of methacrylic acid and methacrolein.
- Mizuno, Noritaka,Tateishi, Masaki,Iwamoto, Masakazu
-
-
Read Online
- Spectroscopy of hydrothermal solutions 18: PH-dependent kinetics of itaconic acid reactions in real time
-
The kinetics of decarboxylation of the α-substituted acrylic acid itaconic acid were analyzed at 280-330 °C, 275 bar, and solution pH25 = 0.8-5.75 using an FTIR spectroscopy flow reactor. As the pH was increased, the observed rate constant initially decreased to a minimum at pH25 = 1.82, then increased and reached its maximum at pH25 = 3.75, and then decreased again up to the limit of study at pH25 = 5.75. The decarboxylation rate depends on the molecular form of itaconic acid in the order of itaconate monoanion > protonated itaconic acid > neutral itaconic acid ≈ itaconate dianion. Insight into possible reasons for this trend was obtained from geometry-optimized structures using density functional theory with the B3LYP method at the 6-31 +G* level.
- Li, Jun,Brill, Thomas B.
-
-
Read Online
- Kinetics of oxidation of α,β-unsaturated aldehydes by quinolinium dichromate
-
A series of α,β-unsaturated aldehydes (crotonaldehyde, cinnamaldehyde, acrylaldehyde, and methacrylaldehyde) were oxidized by quinolinium dichromate in sulfuric acid to the corresponding acids in 50% (v/v) acetic acid water medium. The kinetic data have been discussed with reference to the aldehyde hydration equilibria. The kinetic results support a mechanistic pathway proceeding via a rate-determining oxidative decomposition of the chromate ester of the aldehyde hydrate.
- Chaubey, Girija S.,Das, Simi,Mahanti, Mahendra K.
-
-
Read Online
- Catalysis by heteropoly compounds Part 39. The structure and redox behaviour of vanadium species in molybdovanadophosphoric acid catalysts during partial oxidation of isobutane
-
The states and roles of vanadium of 11-molybdo-1-vanadophosphoric acid (H4PMo11VO40, PMo11V) catalyst in the partial oxidation of isobutane (2-methylpropane) were analysed by EPR, 51V and 31P NMR, IR spectroscopy, and redox titration, and compared with dodecamolybdophosphoric acid (H3PMo12O40, PMo12) catalyst. Thermal treatment of PMo11V at 623 K in O2 caused the elimination of V from the Keggin anion and formed undefined polymeric and a monomeric V species. It was shown based on the redox titration and EPR spectra that the average valency of V in used catalysts significantly changed with the oxygen partial pressure, while that of Mo remained almost unchanged for both PMo11V and PMo12. The selectivities to methacrylic acid (MAA) and methacrolein (MAL) extrapolated to zero conversion were similar for both catalysts, but PMo11V showed a significantly higher selectivity as the conversion increased. This is because the secondary reaction, that is, oxidative decomposition of MAL and MAA, was slower over PMo11V than over PMo12. This was consistent with the marked difference in the reaction order in oxygen pressure, and corresponded to the differences in the above redox properties.
- Inumaru, Kei,Ono, Akiko,Kubo, Hiroshi,Misono, Makoto
-
-
Read Online
- Partial oxidation of 2-methyl-1,3-propanediol to methacrylic acid: experimental and neural network modeling
-
Methacrylic acid (MAA) is a specialty intermediate to produce methyl methacrylate (MMA), which is a monomer for poly methyl methacrylate. Current processes to MMA and MAA rely on expensive feedstocks and multi-step processes. Here we investigate the gas-phase oxidation of 2-methyl-1,3-propanediol (2MPDO) to MAA over heteropolycompounds as effective catalysts, finding that the maximum selectivity to MAA was 41% with 63% conversion of reactant at 250 °C over Cs(NH4)2PMo12O40(VO)Cu0.5. Cesium (Cs) stabilized the catalyst structure at 250 °C, and vanadium(v) and copper (Cu) played a positive role as an oxidant and promoter, respectively. A 0.3 mm nozzle atomized the liquid reactant over the catalyst surface into a μ-fluidized bed reactor. The proposed Artificial Neural Network (ANN) model predicts MAA selectivity based on 2MPDO and oxygen compositions and catalyst components (Cs, V, Cu) as independent factors. The model accounts for 97% of the variance in the data (R2 = 0.97). Vanadium as a catalyst component and oxygen concentration are the two most significant factors. Genetic algorithms (GA) coupled with ANN modeling optimized the input parameters to improve the selectivity. The selectivity to MAA over the optimized catalyst (Cs(NH4)2PMo12O40(VO)Cu0.15) and optimum feed compositions (2MPDO/O2/Ar = 13%/10%/77%) was 43% at 250 °C.
- Darabi Mahboub, Mohammad Jaber,Rostamizadeh, Mohammad,Dubois, Jean-luc,Patience, Gregory S.
-
p. 114123 - 114134
(2016)
-
Read Online
- The role of steam in selective oxidation of methacrolein over H3PMo12O40
-
Role of steam in selective oxidation of methacrolein with molecular oxygen over H3PMo12O40 catalyst was investigated. Addition of steam to feed gas significantly enhanced both catalytic activity and selectivity to methacrylic acid, which were fivefold and twice increases, respectively, under the optimal steam pressure (PH2O = 0.13 atm). Kinetic analysis demonstrated that the addition of steam caused 200-fold increase in the pre-exponential factor for the formation of methacrylic acid, leading to the significant increase in the activity. The steam in the feed gas varied hydrous state of H3PMo12O40 under the reaction conditions, while did not alter redox property, molecular and crystalline structures, and surface area of the catalyst. In the presence of steam at 573 K, three H2O per one H3PMo12O40 were absorbed and hydrated protons like [H3O]+ were formed in the bulk of H3PMo12O40. Methacrolein was adsorbed on the surface of the hydrous catalyst, but not on anhydrous one at all. Based on the results, it was concluded that activation of methacrolein readily occurred on the catalyst in the presence of steam, leading to the significant increase in the pre–exponential factor. Quantum chemical calculation supported the smooth activation of methacrolein by the reaction with [H3O]+ without any transition state.
- Yasuda, Shuhei,Hirata, Jun,Kanno, Mitsuru,Ninomiya, Wataru,Otomo, Ryoichi,Kamiya, Yuichi
-
-
Read Online
- Catalytic activity of V-substituted Cs2te0.2H 0.6 + xPMo12-xVxOn heteropoly compounds in selective oxidation of isobutane
-
A series of Cs2Te0.2H0.6 + xPMo 12 - xVxOn (x = 0-3) heteropoly compounds has been.prepared and tested in the partial oxidation of isobutane. Catalytic tests show that at 350°C very high selectivity to methacrylic acid (60.1%) can be achieved at isobutane conversion of 12.2% over a Cs2.0Te0.2H 1.6PMo11VOn catalyst with only one molybdenum atom per.unit cell substituted by vanadium. The presence of Te4+ in the heteropoly compounds appears to interfere with the dehydrqgenation step and favor the formation of methacrolein and methacrylic acid. Pleiades Publishing, Ltd., 2012.
- Ding, Wenli,Kan, Qiubin,Liu, Heng,Liu, Lulu,Guan, Jingqi
-
-
Read Online
- Characteristics of iron phosphate and its catalytic activity for oxidative dehydrogenation of isobutyric acid
-
In the absence of oxygen, P/Fe = 1.2 catalyst samples are reduced by hydrogen or isobutyric acid to form Fe2P2O7 via Fe3(P2O7)2, while the P/Fe= 1.0 samples are reduced directly to Fe2P2O7; without passing through Fe3(P2O7)2. Fe2P2O7 is oxidized by air to an unknown compound (Y-phase), but not to Fe3(P2O7)2 nor FePO4. The Y-phase is reduced to Fe2P2O7. During the use in the oxidative dehydrogenation of isobutyric acid, freshly calcined catalysts are reduced to Fe3(P2O7)2, while the Fe2P2O7 catalysts are oxidized to Y-phase, though the rates are very slow. The catalytic activity and selectivity are scarcely affected by variation in the structure of the iron phosphate catalyst and in the oxidation states of iron ions. The P/Fe and Fe2+(Fe2++Fe3+) ratios on the surface, which were measured from cooled catalyst samples, are almost the same as those in the bulk.
- Muneyama, Etsuhiro,Kunishige, Atsuhiro,Ohdan, Kyoji,Ai, Mamoru
-
-
Read Online
- Development of a scalable synthesis of GSK183390A, a PPAR α/γ agonist
-
A scalable synthesis of GSK183390A, a PPAR α/γ agonist, is described. This synthesis is highlighted by (1) a regioselective formal 1,3-dipolar cycloaddition reaction between an enamine and a nitrile inline dipole to form a 1,3,5-trisubstmited pyrazole and (2) a regioselective amidomethylation of an o-cresol derivative using 2-chloro-JV- hydroxymethylacetamide.
- Oh, Lynette M.,Wang, Huan,Shilcrat, Susan C.,Hermann, Robert E.,Patience, Daniel B.,Spoors, P. Grant,Sisko, Joseph
-
-
Read Online
- Catalytic selective oxidation of isobutane over Csx(NH 4)3-xHPMo11VO40 mixed salts
-
A series of mixed Keggin-type heteropolysalts Csx(NH 4)3-xHPMo11VO40 with various ammonia/caesium ratios was prepared by the precipitation method and characterized by TGA, N2 adsorption/desorption, XRD, FT-IR, and NH3-TPD techniques. Correlations between the ammonia/caesium ratio and the specific surface area, as well as with the total number of acid sites, were established. Furthermore, the introduction of Cs to the catalytic formulation was beneficial to the stabilization of the Keggin structure and helped limiting the elimination of the V atoms from the primary structure. The as-prepared samples were applied in the catalytic selective oxidation of isobutane at 340 °C under atmospheric pressure. The best results were obtained over Cs1.7(NH4)1.3HPMo 11VO40 with an isobutane conversion of 9.6% and a total selectivity to valuable products (methacrylic acid and methacrolein) of 57.1%. This was explained by the well-balanced acidity and specific surface of this catalyst, promoting the C-H bond activation (adequate acid properties) over a large number of accessible active sites (high acid sites density). the Partner Organisations 2014.
- Jing, Fangli,Katryniok, Benjamin,Dumeignil, Franck,Bordes-Richard, Elisabeth,Paul, Sebastien
-
-
Read Online
- Strong Br?nsted acid-modified chromium oxide as an efficient catalyst for the selective oxidation of methacrolein to methacrylic acid
-
Gas–phase oxidation of methacrolein to methacrylic acid was carried out over an acid-modified Cr2O3/SiO2 catalyst. While only total oxidation occurred over bare Cr2O3/SiO2, the acid-modified Cr2O3/SiO2 showed catalytic activity for the formation of methacrylic acid. In particular, H3PW12O40 strong Br?nsted acid was the most effective modifier for improving both activity and selectivity. The interface between Cr2O3 and H3PW12O40 particles on SiO2 appears to be responsible for the formation of active sites for the selective formation of methacrylic acid. The strong Br?nsted acid would help the activation of methacrolein through rendering it more electrophilic, which is a key step for the formation of methacrylic acid over the present catalyst.
- Yasuda, Shuhei,Iwakura, Atsuki,Hirata, Jun,Kanno, Mitsuru,Ninomiya, Wataru,Otomo, Ryoichi,Kamiya, Yuichi
-
-
Read Online
- Kinetics and mechanism of the gas-phase elimination of primary, secondary and tertiary 2-acetoxycarboxylic acids
-
The gas-phase elimination kinetics of the title compounds were examined over the temperture range 220.1 -349.0°C and pressure range 19-120 Torr. These reactions proved to he homogeneous and unimolecular and to follow a first-order rate law. The overall rate coefficients arc expressed by the following Arrhenius equations: for 2-acetoxyacetic acid, logk1 (s-1) = (12.03 ± 0.28) - (170.8 ± 3.2) kJ mol-1 (2.303RT)-1 : for 2-acetoxypropionic acid, logk1 (s-1) = (13.16 ± 0.24) - (174.2 ± 2.6) kJ mol-1 (2.30RT)-1 : for 2-acetoxy-2-methylproponic acid, logk1 (s-1) = (13.40 ± 0.72) - (160.9 ± 5.03) kJ mol-1 (2.303RT)-1. The products of the acetoxyacids are acetic-acid, the corresponding carbonyl compound and CO gas. except for 2-acetoxy-2-methylpropionic acid. which undergoes a parallel elimination to give methacryclic acid and acetic acid. The rates of elimination are found to increase from primary to tertiary carbon bearing the acetoxy group. The mechanism appears to proceed through a discrete polar five-membered cyclic transition state, where the acidic hydrogen of the COOH assists the leaving acetoxy group, followed by the participation of the carbonyl oxygen for α-lactone formation. The unstable α-lactone intermediate decomposes rapidly into the corresponding carbonyl compound and CO gas. The importance of the acidic H of the COOH assistance in the acetoxy acid mechanisms may be revealed in the elimination kinetics of methyl 2-acetoxypropionate. This substrate was studied in the ranges 370.0-430.0°C and 36-125 Torr This reaction is homogeneous, unimolecular and follows a first-order rate law. The products are methyl acrylate and acetic acid. The rate coefficients is given by the equation logk1 (s-1) = (12.63 ± 0.35) - (201.7 ± 4.4) kJ mol-1 (2.303RT)-1. Copyright
- Chuchani, Gabriel,Dominguez, Rosa M.,Herize, Armando,Romero, Roman
-
-
Read Online
- Ni-Catalyzed enantioselective reductive arylcyanation/cyclization of: N -(2-iodo-aryl) acrylamide
-
A Ni/(S,S)-BDPP-catalyzed intramolecular Heck cyclization of N-(2-iodo-aryl) acrylamide with 2-methyl-2-phenylmalononitrile was developed to give oxindoles with good enantioselectivities. We found that utilizing such an electrophilic cyanation reagent cou
- Dong, Kaiwu,Ren, Xinyi,Shen, Chaoren,Wang, Guangzhu
-
supporting information
p. 1135 - 1138
(2022/02/03)
-
- Ligand-controlled divergent dehydrogenative reactions of carboxylic acids via C–H activation
-
Dehydrogenative transformations of alkyl chains to alkenes through methylene carbon-hydrogen (C–H) activation remain a substantial challenge. We report two classes of pyridine-pyridone ligands that enable divergent dehydrogenation reactions through palladium-catalyzed b-methylene C–H activation of carboxylic acids, leading to the direct syntheses of a,b-unsaturated carboxylic acids or g-alkylidene butenolides. The directed nature of this pair of reactions allows chemoselective dehydrogenation of carboxylic acids in the presence of other enolizable functionalities such as ketones, providing chemoselectivity that is not possible by means of existing carbonyl desaturation protocols. Product inhibition is overcome through ligand-promoted preferential activation of C(sp3)–H bonds rather than C(sp2)–H bonds or a sequence of dehydrogenation and vinyl C–H alkynylation. The dehydrogenation reaction is compatible with molecular oxygen as the terminal oxidant.
- Wang, Zhen,Hu, Liang,Chekshin, Nikita,Zhuang, Zhe,Qian, Shaoqun,Qiao, Jennifer X.,Yu, Jin-Quan
-
p. 1281 - 1285
(2021/12/10)
-
- A CATALYST AND A PROCESS FOR THE PRODUCTION OF ETHYLENICALLY UNSATURATED CARBOXYLIC ACIDS OR ESTERS
-
The invention discloses a catalyst comprising a silica support, a modifier metal and a catalytic alkali metal. The silica support has a multimodal pore size distribution comprising a mesoporous pore size distribution having an average pore size in the range 2 to 50 nm and a pore volume of said mesopores of at least 0.1 cm3/g, and a macroporous pore size distribution having an average pore size of more than 50 nm and a pore volume of said macropores of at least 0.1 cm3/g. The level of catalytic alkali metal on the silica support is at least 2 mol%. The modifier metal is selected from Mg, B, Al, Ti, Zr and Hf. The invention also discloses a method of producing the catalyst, a method of producing an ethylenically unsaturated carboxylic acid or ester in the presence of the catalyst, and a process for preparing an ethylenically unsaturated acid or ester in the presence of the catalyst.
- -
-
Page/Page column 40
(2021/02/05)
-
- Method for synthesizing methacrylic acid by decarboxylating itaconic acid
-
The invention relates to a method for synthesizing methacrylic acid by decarboxylating itaconic acid. The method comprises the following steps: adding water, itaconic acid and a catalyst into a high-pressure kettle, sealing the high-pressure kettle, introducing nitrogen, and conducting reacting at 190-260 DEG C for 1-8 hours to obtain methacrylic acid, wherein the catalyst is a modified hydroxyapatite catalyst with a general formula of M10(ZO4)6(X) 2, M is one or two selected from a group consisting of Ca, Mg, Ba, Fe or Sr, ZO4 is PO4, and X is OH. The modified hydroxyapatite catalyst has the advantages of being high in activity and selectivity, easy to separate, environmentally friendly and the like, an itaconic acid conversion rate is larger than 98%, and the selectivity of the target product methacrylic acid can reach 75% or above at most.
- -
-
Paragraph 0043-0050
(2021/11/06)
-
- High-performance 3D printing UV-curable resins derived from soybean oil and gallic acid
-
Developing sustainable 3D printing materials has attained intensive interest due to the rapid growth of the 3D printing industry and the concerns on depletion of fossil resources and environmental pollution. In this work, a novel biobased UV-curable oligomer (GMAESO) was firstly synthesized from epoxidized soybean oil (ESO) and gallic acid (GA) via a 'green' one pot method. The obtained biobased oligomer possessed a biobased content of 82.9%. By co-photopolymerization of the obtained oligomer with a hydroxyethyl methacrylate (HEMA) diluent, a series of UV-curable materials were prepared, and their properties as well as curing behaviors were investigated. Notably, the resulting GMAESO resins with high HEMA contents (50-60%) showed low viscosities (52-93 mPa s) and excellent thermal and mechanical properties (a Tg of 128-130 °C, Tp >430 °C, a tensile strength of 42.2-44.4 MPa, etc.) which were comparable or superior to a commercial product. Furthermore, the optimal resin (GMAESO with 50% HEMA) was used for digital light processing (DLP) 3D printing. The resin showed lower penetration depth (0.277 mm) than the commercial resin, thus different-structured objects with high resolution were successfully printed. In general, the developed bio-based UV-curable resins are very promising for application in the 3D printing industry.
- Cheng, Jianwen,Hu, Lihong,Hu, Yun,Huang, Jia,Liu, Chengguo,Shang, Qianqian,Yu, Xixi,Zhang, Jinshuai,Zhou, Yonghong,Zhu, Guoqiang
-
p. 5911 - 5923
(2021/08/23)
-
- Supported Rb- or Cs-containing HPA catalysts for the selective oxidation of isobutane
-
Silica-supported catalysts based on Keggin-type heteropolyacids (HPAs) containing rubidium or cesium as counter cations have been prepared by the impregnation method and evaluated in the selective oxidation of isobutane to methacrolein and methacrylic acid. The catalysts were characterized by various techniques such as XRD, N2 physisorption, TGA, Raman spectroscopy, H2-TPR, and NH3-TPD in order to study their thermal stability, structural, and textural properties, acidity and reducibility. It was evidenced that the reducibility of the Keggin type HPAs was improved by supporting the active phase on SiO2. A loading of 40 wt% was the optimum for the selective oxidation of isobutane (IBAN) to methacrylic acid (MAA). The selectivities to MAA and methacrolein (MAC) at given conversion were increased when Cs+ was used as counter cation compared to Rb+. The same trend was observed for mono- and di-vanado-substituted phosphomolybdic acid, whereby the performance followed the order: CsV1/SiO2 > RbV1/SiO2 > CsV2/SiO2 > RbV2/SiO2. The density of acid sites was correlated to the catalytic activity, which underlines the importance of the acid sites for alkane activation.
- Dumeignil, Franck,Katryniok, Benjamin,Paul, Sébastien,Zhang, Li
-
-
- Method for preparing catalyst
-
The present invention relates to a method for preparing a catalyst and a method for preparing unsaturated carboxylic acid using the catalyst prepared according to the preparation method. According to the method for preparing a catalyst, unsaturated carboxylic acid can be provided from an unsaturated aldehyde with a high conversion rate and selectivity.
- -
-
Page/Page column 9
(2020/03/14)
-
- PROCESS FOR PRODUCING METHYL METHACRYLATE
-
The present invention relates to a method for producing methyl methacrylate. According to the present invention, provided is a method for producing methyl methacrylate, which is capable of securing the safety of a process, while improving the catalyst life and increasing the production amount of methyl methacrylate.
- -
-
Paragraph 0181-0222
(2020/10/03)
-
- A PROCESS FOR THE PRODUCTION OF A CATALYST, A CATALYST THEREFROM AND A PROCESS FOR PRODUCTION OF ETHYLENICALLY UNSATURATED CARBOXYLIC ACIDS OR ESTERS
-
The present invention relates to a process for producing a catalyst. The process comprises the steps of: a) providing an uncalcined metal modified porous silica support wherein the modifier metal is selected from one or more of boron, magnesium, aluminium, zirconium, hafnium and titanium, wherein the modifier metal is present in mono- or dinuclear modifier metal moieties; b) optionally removing any solvent or liquid carrier from the modified silica support; c) optionally drying the modified silica support; d) treating the uncalcined metal modified silica support with a catalytic metal to effect adsorption of the catalytic metal onto the metal modified silica support; and e) calcining the impregnated silica support of step d). The invention extends to an uncalcined catalyst intermediate and a method of producing a catalyst by providing a porous silica support having isolated silanol groups.
- -
-
Page/Page column 31-32
(2020/09/30)
-
- Hexagonal Mo/V/W mixed oxide as a catalyst for the partial oxidation of methacrolein to methacrylic acid
-
This work evaluates for the first time the catalytic performance of a hexagonal Mo/V/W mixed oxide, the so-called h-phase, in the partial oxidation of methacrolein to methacrylic acid. Three catalysts with different phase compositions were compared. One catalyst predominantly contained h-phase, a further consisted of the well-known M1 phase, and a third catalyst was composed of both, h-phase and M1, in similar amounts. The selectivity of the h-phase catalyst is comparable to that of M1.
- Kraushaar-Czarnetzki, Bettina,Sennerich, Maximilian,Weidler, Peter
-
-
- Macrolactam Synthesis via Ring-Closing Alkene-Alkene Cross-Coupling Reactions
-
Reported herein is a practical method for macrolactam synthesis via a Rh(III)-catalyzed ring closing alkene-alkene cross-coupling reaction. The reaction proceeded via a Rh-catalyzed alkenyl sp2 C-H activation process, which allows access to macrocyclic molecules of different ring sizes. Macrolactams containing a conjugated diene framework could be easily prepared in high chemoselectivities and Z,E stereoselectivities.
- Goh, Jeffrey,Loh, Teck-Peng,Maraswami, Manikantha
-
supporting information
p. 9724 - 9728
(2020/12/21)
-
- PROCESS FOR PREPARING N-METHYL(METH)ACRYLAMIDE
-
The invention relates to a process for preparing N-methyl(meth)acrylamide and to the uses thereof.
- -
-
Page/Page column 5-6
(2020/02/16)
-
- METHOD FOR PREPARING LOW-GRADE UNSATURATED FATTY ACID ESTER
-
Provided is a method for preparing a lower unsaturated fatty acid ester, which comprises carrying out an aldol condensation reaction between dimethoxymethane (DMM) and a lower acid or ester with a molecular formula of R1—CH2—COO—R2 on an acidic molecular sieve catalyst in an inert atmosphere to obtain a lower unsaturated fatty acid or ester(CH2═C(R1)—COO—R2), wherein R1 and R2 are groups each independently selected from the group consisting of H- and C1-C4 saturated alkyl group.
- -
-
Paragraph 0050; 0054
(2020/03/09)
-
- Cobalt-catalyzed carboxylation of aryl and vinyl chlorides with CO2
-
The transition-metal-catalyzed carboxylation of aryl and vinyl chlorides with CO2 is rarely studied, and has been achieved only with a Ni catalyst or combination of palladium and photoredox. In this work, the cobalt-catalyzed carboxylation of aryl and vinyl chlorides and bromides with CO2 has been developed. These transformations proceed under mild conditions and exhibit a broad substrate scope, affording the corresponding carboxylic acids in good to high yields.
- Wang, Yanwei,Jiang, Xiaomei,Wang, Baiquan
-
supporting information
p. 14416 - 14419
(2020/12/01)
-
- Preparation method for methyl methacrylate
-
The invention relates to a preparation method for methyl methacrylate. The preparation method comprises the following steps: introducing oxygen into isobutyraldehyde at a temperature of 50 to 60 DEG Cand a pressure of 0.1 to 0.3 MPa in the presence of a solid oxidation catalyst for oxidization of the isobutyraldehyde, carrying out a reaction at an oxygen space velocity of 1000 to 1200 hours for 10 to 36 hours, and separating the solid oxidation catalyst so as to obtain an isobutyric acid solution; adding a halogen element and acetic anhydride into the isobutyric acid solution, and carrying out a reaction at a normal pressure and a temperature of 80 to 100 DEG C for 1 to 5 hours so as to obtain a halogenated isobutyric acid solution; adding sodium hydroxide and first methanol into thehalogenated isobutyric acid solution, carrying out a reaction at a normal pressure and a temperature of 50 to 80 DEG C for 5 to 15 hours, and carrying out filtering to remove impurities so as to obtain a methacrylic acid solution; and adding second methanol, an ionic liquid catalyst and cyclohexane into the methacrylic acid solution, carrying out a reaction at 70 to 90 DEG C for 2 to 12 hours, andcarrying out filtering and separation so as to obtain the methyl methacrylate. The preparation method provided by the invention has simple preparation process and high yield.
- -
-
Paragraph 0036-0049
(2019/11/12)
-
- Device for producing methacrylic acid
-
The present invention relates to a methacrylic acid production apparatus. The present invention provides a methacrylic acid production apparatus capable of suppressing the adhesion of precipitates inthe production apparatus. The methacrylic acid production apparatus comprise: a first reactor for obtaining methacryl from isobutylene and/or TBA and oxygen; a second reactor for reacting methacryl and oxygen to obtain the methacrylic acid; a first line connected to the first reactor and the second reactor; and a second line connected to the first line and supplying a stream containing 15% by massor more of oxygen to the first line, the second line having a heating unit.
- -
-
Paragraph 0052-0061
(2019/10/08)
-
- A CATALYST AND A PROCESS FOR THE PRODUCTION OF ETHYLENICALLY UNSATURATED CARBOXYLIC ACIDS OR ESTERS
-
A catalyst has a modified silica support and comprises a modifier metal, zirconium and/or hafnium, and a catalytic metal on the modified support. The catalyst has at least a proportion, typically, at least 25%, of modifier metal present in moieties having a total of up to 2 modifier metal atoms. The moieties may be derived from a monomeric and/or dimeric cation source. A method of production:- provides a silica support with isolated silanol groups with optional treatment to provide isolated silanol groups (-SiOH) at a level of 2; contacting the optionally treated silica support with a monomeric zirconium or hafnium modifier metal compound to effect adsorption onto the support; optionally calcining the modified support for a time and temperature sufficient to convert the monomeric zirconium or hafnium compound adsorbed on the surface to an oxide or hydroxide of zirconium or hafnium in preparation for catalyst impregnation. A method of producing an ethylenically unsaturated carboxylic acid or ester, typically, an a, β ethylenically unsaturated carboxylic acid or ester, comprising the steps of contacting formaldehyde or a suitable source thereof with a carboxylic acid or ester in the presence of catalyst and optionally in the presence of an alcohol, wherein said catalyst is used.
- -
-
Page/Page column 45-50
(2019/04/11)
-
- Acrylonitrile Derivatives from Epoxide and Carbon Monoxide Reagents
-
The present invention is directed to reactor systems and processes for producing acrylonitrile and acrylonitrile derivatives. In preferred embodiments of the present invention, the processes comprise the following steps: introducing an epoxide reagent and carbon monoxide reagent to at least one reaction vessel through at least one feed stream inlet; contacting the epoxide reagent and carbon monoxide reagent with a carbonylation catalyst to produce a beta-lactone intermediate; polymerizing the beta-lactone intermediate with an initiator in the presence of a metal cation to produce a polylactone product; heating the polylactone product under thermolysis conditions to produce an organic acid product; optionally esterifying the organic acid product to produce one or more ester products; and reacting the organic acid product and/or ester product with an ammonia reagent under ammoxidation conditions to produce an acrylonitrile product.
- -
-
Paragraph 0266-0270
(2019/01/15)
-
- METHOD FOR PURIFYING METHACRYLIC ACID AND METHOD FOR PRODUCING METHACRYLIC ACID
-
A method for purifying methacrylic acid, including mixing raw material methacrylic acid and methanol; precipitating a crystal of methacrylic acid from the mixed solution; and separating the crystal and mother liquor, wherein the raw material methacrylic acid and methanol are mixed so that a concentration of methanol in the mixed liquid is 3.0 to 3.75% by mass, and the crystal of methacrylic acid is precipitated from the mixed solution in a cooling crystallization vessel.
- -
-
Paragraph 0092
(2019/02/19)
-
- PROCESS FOR THE PREPARATION OF ELAFIBRANOR AND NOVEL SYNTHESIS INTERMEDIATES
-
The present invention relates to a process for the preparation of elafibranor and novel synthesis intermediates.
- -
-
Page/Page column 11
(2019/02/15)
-
- Synthesis of bio-based methacrylic acid from biomass-derived itaconic acid over barium hexa-aluminate catalyst by selective decarboxylation reaction
-
An environmentally-benign, efficient and inexpensive high-surface-area barium hexa-aluminate (BaAl12O19, BHA) was developed as a catalyst for the decarboxylation of the biomass-derived itaconic acid (IA) to bio-based methacrylic acid (MAA). A maximal 50% final yield of MAA with a high product selectivity was obtained under relatively mild synthesis reaction conditions (250 °C; 20 bar N2). The reported selective MAA production was elevated, operating process characteristics were significantly less harsh, and no depleting critical raw materials were utilized when paralleled to the procedures with alkaline mineral bases, noble metal-containing heterogeneous catalysis systems and unrenewable feed resources (e.g. isobutene), applied previously. It was found that the doping of palladium on BHA support (Pd@BHA) did not improve MAA productivity. The effect of the time (25–300 min), temperature (175–275 °C), pressure (10–40 bar), reacting substrate concentration (0.10–0.19 mol L–1), metallic oxide mass (0.5–3.0 g) and type on IA conversion, MAA content MAA content and rates was determined, examining also recyclability. BHA catalyst was characterized with various structural techniques, such as energy-dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), CO2 temperature-programmed desorption (TPD), scanning electron microscopy (SEM) and N2 physisorption.
- Bohre, Ashish,Novak, Uro?,Grilc, Miha,Likozar, Bla?
-
-
- Methacrylic acid production method
-
A method of producing methacrylic acid using a hydrotalcite catalyst and subcritical water is described.
- -
-
Page/Page column 10; 16
(2018/12/11)
-
- BIO-BASED METHACRYLIC ACID AND OTHER ALKENOIC-DERIVED MONOMERS VIA CATALYTIC DECARBOXYLATION
-
A novel method for the catalytic selective decarboxylation of a starting material to produce an organic acid is disclosed. According to at least one embodiment, the method may include placing a reaction mixture into a reaction vessel, the reaction mixture including a solvent, a starting material, and a catalyst, subjecting the reaction mixture to a predetermined pressure and temperature, and allowing the reaction to continue for 1-3 hours. The starting material may be at least one of a dicarboxylic acid, a tricarboxylic acid, and an anhydride of a dicarboxylic or tricarboxylic acid. As an exemplary embodiment, itaconic acid may be a starting material and the organic acid may be methacrylic acid. The predetermined temperature may be 250° C. or less, and the reaction pressure may be less than 425 psi. Further, a polymerization inhibitor may be used.
- -
-
Paragraph 0060-0061
(2018/04/26)
-
- METHOD FOR THE PRODUCTION OF METHYLSUCCINIC ACID AND THE ANHYDRIDE THEREOF FROM CITRIC ACID
-
A process for the preparation of methylsuccinic acid in any form, including its salts, its mono- and diester derivatives and the anhydride thereof, which comprises reacting citric acid or a derivative thereof in decarboxylation conditions, said process comprising (i) reacting citric acid or mono- and diester derivatives thereof in a non- aqueous solvent, specifically excluding alcohols, on a metallic catalyst at a temperature between 50 to 400°C and under a partial hydrogen pressure from 0.1 to 50 bar or (ii) reacting citric acid or any salt thereof or mono-, di- and triester derivatives thereof on a metallic catalyst in solvents comprising at least 5% water, at a temperature of from 50 to 400°C under a hydrogen partial pressure from 0.1 to 400 bar
- -
-
Page/Page column 15
(2018/04/21)
-
- PROCESS FOR THE BIOLOGICAL PRODUCTION OF METHACRYLIC ACID AND DERIVATIVES THEREOF
-
A process of producing methacrylic acid and/or derivatives thereof including the following steps: (a) biologically converting isobutyryl-CoA into methacrylyl-CoA by the action of an oxidase; and (b) converting methacrylyl-CoA into methacrylic acid and/or derivatives thereof. The invention also extends to microorganisms adapted to conduct the steps of the process.
- -
-
-
- Ni-Catalyzed Enantioselective Reductive Diarylation of Activated Alkenes by Domino Cyclization/Cross-Coupling
-
A Ni-catalyzed enantioselective reductive diarylation of activated alkenes by domino cyclizative/cross-coupling of two aryl bromides is developed. This reaction proceeds under very mild conditions and shows broad substrate scope, without requiring the use of preformed organometallic reagents. Moreover, this approach provides direct access to various bis-heterocycles bearing all-carbon quaternary centers in synthetically useful yields (up to 81%) with excellent enantioselectivity (>30 examples, 90-99% ee).
- Wang, Kuai,DIng, Zhengtian,Zhou, Zhijun,Kong, Wangqing
-
supporting information
p. 12364 - 12368
(2018/10/05)
-
- Polyoxometalate catalysts with co-substituted VO2+ and transition metals and their catalytic performance for the oxidation of isobutane
-
Cs-Salts of the Keggin-type phosphomolybdic acid with simultaneous doping of VO2+ and different transition metals are prepared, characterized and tested as catalysts for the oxidation of isobutane to methacrylic acid under isobutane-rich condit
- Liu, Yanchun,He, Jingfang,Chu, Wenling,Yang, Weishen
-
p. 5774 - 5781
(2018/11/25)
-
- METHOD FOR PRODUCING ALPHA-HYDROXY CARBOXYLIC ESTERS IN THE GAS PHASE
-
The present invention relates to a process for preparing alpha-hydroxycarboxylic esters from the alcoholysis of alpha-hydroxycarboxam ides in the gas phase, characterized in that the conversion is effected in the presence of water.
- -
-
Paragraph 0054
(2017/06/23)
-
- PROCESS FOR PRODUCTION OF A SILICA-SUPPORTED ALKALI METAL CATALYST
-
A process for regenerating a silica-supported depleted alkali metal catalyst is described. The level of alkali metal on the depleted catalyst is at least 0.5 mol % and the silica support is a zero-gel. The process comprises the steps of contacting the silica supported depleted alkali metal catalyst with a solution of a salt of the alkali metal in a solvent system that has a polar organic solvent as the majority component. A re-impregnated catalyst prepared by the process of the invention any comprising a silica zero-gel support and a catalytic metal selected from an alkali metal in the range 0.5-5 mol % on the catalyst, wherein the surface area of the silica support is 2/g is also described. The invention is applicable to a process for preparing an ethylenically unsaturated acid or ester comprising contacting an alkanoic acid or ester of the formula R1—CH2—COOR3, with formaldehyde or a suitable source of formaldehyde.
- -
-
Paragraph 0085-0087
(2017/06/12)
-
- Methacrylic acid
-
PROBLEM TO BE SOLVED: To provide a method for manufacturing methacrylic acid in a favorable productivity over an extended period.SOLUTION: The provided method for manufacturing methacrylic acid is a method for manufacturing methacrylic acid by feeding methacrolein, isobutylene, and oxygen into a methacrylic acid manufacturing reactor furnished with a catalyst layer including a catalyst for manufacturing methacrylic acid and by oxidizing the methacrolein continuously wherein the maximal temperature of the catalyst layer is 330°C or below. It is desirable for the maximal temperature of the catalyst layer to be controlled at 330°C or below by adjusting the feeding quantity of the isobutylene.
- -
-
Paragraph 0062
(2017/05/18)
-
- Switchable C-H Functionalization of N-Tosyl Acrylamides with Acryloylsilanes
-
A controllable Rh-catalyzed protocol to access alkylation and alkenylation-annulation of N-tosyl acrylamide with acryloyl silane is reported. In contrast to the directing group or catalyst-dependent divergent sp2 C-H alkylation/alkenylation, the intrinsic property of acryloylsilane allows the switchable reaction manifold, thereby affording either alkylation or annulation products with slight modification of the reaction conditions.
- Song, Shengjin,Lu, Ping,Liu, Huan,Cai, Sai-Hu,Feng, Chao,Loh, Teck-Peng
-
supporting information
p. 2869 - 2872
(2017/06/13)
-
- Oxidative Esterification of Methacrolein to Methyl Methacrylate over Gold Nanoparticles on Hydroxyapatite
-
The catalytic production of methyl methacrylate through the direct oxidative esterification of methacrolein is important in terms of green chemistry and sustainable development. In the present work, Au nanoparticles supported on three needle-like, lamella-like, and rodlike hydroxyapatites were synthesized. We demonstrated that needle-like hydroxyapatite could facilitate the higher dispersion of Au species because of its high specific surface area, and the strong interaction between the Au nanoparticles and the support resulted in the formation of more surface defects because of the existence of partially encapsulated Au particles by the needle-like hydroxyapatite. The surface defects were related closely to the generation of strong basic sites. Compared with the other two materials, the Au supported on the needle-like hydroxyapatite catalyst, which had a large amount of surface acid–base sites, exhibited a much higher catalytic activity and selectivity to methyl methacrylate in the direct oxidative esterification of methacrolein with methanol under mild reaction conditions (i.e., ambient pressure, low reaction temperature of 70 °C, and low methanol/aldehyde ratio of 8:1). The superior catalytic performance of the Au supported on needle-like hydroxyapatite catalyst was attributable to a cooperative effect between abundant acid–base sites for the preferential chemisorption of methacrolein and highly dispersed active Au species for the favorable formation of β-hydride and oxygen activation. The present findings open a new and promising route for the practical production of methyl methacrylate using high-performance hydroxyapatite-supported metal catalyst systems.
- Gao, Jun,Fan, Guoli,Yang, Lan,Cao, Xinzhong,Zhang, Peng,Li, Feng
-
p. 1230 - 1241
(2017/04/14)
-
- OZONE-ACTIVATED NANOPOROUS GOLD AND METHODS OF ITS USE
-
The invention relates to nanoporous gold nanoparticle catalysts formed by exposure of nanoporous gold to ozone at elevated temperatures, as well as methods for production of esters and other compounds.
- -
-
Page/Page column 7
(2018/01/17)
-
- CATALYST FOR USE IN PRODUCTION OF METHYL METHACRYLATE, AND METHOD FOR PRODUCING METHYL METHACRYLATE
-
According to the present invention, a molded catalyst for use in the production of methyl methacrylate can be provided. The molded catalyst comprises synthetic faujasite-type zeolite and a layered magnesium silicate compound, wherein the sulfur content in the layered magnesium silicate compound is 0.10% by weight or less. According to the present invention, a method for producing methyl methacrylate can also be provided. The method is characterized by comprising a step of carrying out a gas-phase catalytic reaction of methyl α-hydroxyisobutyrate using the above-mentioned molded catalyst for use in the production of methyl methacrylate.
- -
-
Paragraph 0046
(2017/04/04)
-
- METHOD FOR PRODUCING (METH)ACRYLIC ACID
-
The present invention provides a (meth)acrylic acid-producing method capable of suppressing formation of carbides so that the production yield of (meth)acrylic acid is enhanced. In such a method, (meth)acrylic acid is produced through gas-phase catalytic oxidation reactions of (meth)acrolein by using molecular oxygen in a fixed-bed reactor configured to have a packed layer containing a packing material and a catalyst layer formed with a catalyst containing at least molybdenum and vanadium. The packed layer contains a packing material that has been used at least once for above gas-phase catalytic oxidation reactions, and the catalyst is present in the packed layer at 0.001?0.15 mass % of the total amount of the packing material.
- -
-
Paragraph 0050; 0051
(2016/10/04)
-
- METHOD FOR PRODUCING (METH)ACRYLIC ACID
-
The present invention provides a (meth)acrylic acid-producing method capable of suppressing formation of carbides so that the production yield of (meth)acrylic acid is enhanced. In such a method, (meth)acrylic acid is produced through gas-phase catalytic oxidation reactions of (meth)acrolein by using molecular oxygen in a fixed-bed reactor configured to have a packed layer containing a packing material and a catalyst layer formed with a catalyst containing at least molybdenum and vanadium. The packed layer contains a packing material that has been used at least once for above gas-phase catalytic oxidation reactions, and the catalyst is present in the packed layer at 0.001~0.15 mass% of the total amount of the packing material.
- -
-
Paragraph 0046-0055
(2017/01/26)
-
- A PROCESS FOR THE PRODUCTION OF ETHYLENICALLY UNSATURATED CARBOXYLIC ACIDS OR ESTERS
-
The present invention relates to a process for the production of an ethylenically unsaturated carboxylic acid or ester, preferably α,? ethylenically unsaturated carboxylic acids or esters, by the liquid phase reaction of formaldehyde or a suitable source thereof with a non-cyclic carboxylic acid ester in the presence of a basic metal salt.
- -
-
Page/Page column 26-28
(2016/10/31)
-
- NITRIDED MIXED OXIDE CATALYST SYSTEM AND A PROCESS FOR THE PRODUCTION OF ETHYLENICALLY UNSATURATED CARBOXYLIC ACIDS OR ESTERS
-
The invention relates to a method of producing an ethylenically unsaturated carboxylic acid or ester, preferably an α, β ethylenically unsaturated carboxylic acid or ester. The method includes contacting formaldehyde or a suitable source thereof with a carboxylic acid or ester in the presence of a catalyst and optionally in the presence of an alcohol. The catalyst comprises a nitrided metal oxide having at least two types of metal cations, M1 and M2, wherein M1 is selected from the metals of group 2, 3, 4, 13 (called also IIIA) or 14 (called also IVA) of the periodic table and M2 is selected from the metals of groups 5 or 15 (called also VA) of the periodic table. The invention extends to a catalyst system.
- -
-
Paragraph 0102; 0103
(2016/10/31)
-
- METHOD FOR PRODUCING UNSATURATED ACID ESTER OR UNSATURATED ACID
-
The present invention relates to a method for producing an unsaturated-acid ester or an unsaturated acid, containing a step of reacting a compound (1) represented by the following formula (1) with a compound represented by the following formula (2) (excluding the compound (1)) in the presence of a Lewis acid catalyst at a temperature of the boiling point of the compound (1) or higher and 350° C. or lower, thereby obtaining products including a compound represented by the following formula (3): (in formula (1) and formula (3), R1, R2 and R4 each independently may be hydrogen atom or an alkyl group, R3 and R5 each independently are hydrogen atom or a deuterium atom, and X is a halogen atom; in formula (2) and formula (3), R6 may be hydrogen atom, an alkyl group or an aryl group, and R7 is hydrogen atom or a deuterium atom).
- -
-
Paragraph 0151-0157
(2016/06/01)
-
- PREPARATION OF NON-ISOCYANATE URETHANE (METH) ACRYLATES FOR URETHANE FUNCTIONAL LATEX
-
A urethane-functional (meth)acrylate monomer is provided that is defined by the formula where R1 is a monovalent organic group, R2 is a hydrogen atom or a monovalent organic group, and R3 is a hydrogen atom or an alkyl group. The urethane-functional (meth)acrylate monomer may be polymerized and advantageously provides improved mechanical properties such as tensile modulus, tensile strength and elongation-at-break tensile modulus, tensile strength and elongation-at-break.
- -
-
Paragraph 0075
(2016/10/17)
-
- An Oxidative Route for the Production of Methyl Methacrylate: A Study Over Iron Phosphate Catalysts
-
Abstract: An iron phosphate catalyst prepared using the ammonia gel method was supported on silica (CAT 1) and a commercial iron phosphate catalyst was supported on silica using the wet impregnation method (CAT 2). The XRD patterns of both the catalysts showed the presence of quartz-like iron phosphate and a tridymite like phase. In situ XRD under a reducing environment and TPR showed the formation of iron pyrophosphate for both the catalysts at 500?°C. The M?ssbauer spectra of the catalysts were similar and showed the presence of the ferric ion only. NH3-TPD revealed the presence of Lewis and Br?nsted acidic sites on both the catalysts. Oxidative dehydrogenation reactions of methyl iso-burate (MIB) were carried out using a continuous flow fixed bed reactor at contact times of 0.4 and 0.8?s. The conversion of MIB was marginally higher at a contact time of 0.8?s. CAT 2 gave an 11?% yield of methyl methacryalate (MMA) compared to 21?% over CAT 1 at a contact time of 0.8?s. The conversion of MIB increased with co-feeding water. A maximum conversion of MIB (82?%) was obtained at 400?°C, giving a yield of 20?% MMA at a contact time of 0.8?s over CAT 1. However, co-feeding water increased the hydrolysis reaction also, which increased the yield towards iso-butyric acid and methacrylic acid. Graphical Abstract: [Figure not available: see fulltext.]
- Harilal, Avinash,Dasireddy, Venkata D. B. C.,Friedrich, Holger B.
-
p. 1169 - 1181
(2016/07/06)
-
- Process for preparing methacrylic acid or methacrylic esters
-
The present invention relates to a process for the preparation of methacrylic acid or methacrylic esters, comprising the process steps of IA) preparation of 3-hydroxyisobutyric acid by a process comprising the process step of bringing a cell which has been genetically modified in comparison with its wild type in such a way that it is capable of forming more 3-hydroxyisobutyric acid, or polyhydroxyalkanoates based on 3-hydroxyisobutyric acid in comparison with its wild type, into contact with a nutrient medium comprising, as carbon source, carbohydrates, glycerol, carbon dioxide, methanol, L-valine or L-glutamate under conditions under which 3-hydroxyisobutyric acid or polyhydroxyalkanoates based on 3-hydroxyisobutyric acid are formed from the carbon source, if appropriate, isolation of the 3-hydroxyisobutyric acid from the nutrient medium and also, if appropriate, neutralization of the 3-hydroxyisobutyric acid, IB) dehydration of the 3-hydroxyisobutyric acid with formation of methacrylic acid and also, where appropriate, esterification methacrylic acid. The invention also relates to a process for the preparation of polymethacrylic acid or polymethacrylic esters.
- -
-
Page/Page column 49; 54
(2016/02/05)
-
- PROCESS FOR PRODUCING METHACRYLIC ACID
-
The present invention refers to, methacrolein oxidation by molecular oxygen the gas phase by the removing means in the manufacture of a methacrylic acid, use a catalyst for a long time a method in for providing. In the present invention, molybdenum and a phosphorous bearing composite oxide a in the presence of a catalyst comprising a methacrolein oxidation by molecular oxygen the gas phase by the removing means, in the manufacture of a methacrylic acid, 305 °C hereinafter reaction temperatures of 285 °C or more of said range to a constant value under control by response rate, reaction pressure capable of changing stepwise or continuously concurrently with controlling pressure with high response and high, said pressure control simultaneously or independently among reaction gases of molecular oxygen/raw material stepwise or continuously molar ratio in the range of selectively changing the mole ratio control, the portable telephone sends a.
- -
-
Paragraph 0054-0056
(2016/12/22)
-
- PROCESS FOR THE PRODUCTION OF METHACRYLIC ACID
-
Disclosed is a method of making methacrylic acid, or a carboxylic derivative thereof, from itaconic acid, isomers, or precursors thereof. A starting material comprising an acid selected from the group consisting of itaconic acid, citraconic acid, mesaconic acid, citric acid, aconitic acid, isocitric acid and mixtures thereof, is subjected to contact with 0.1 eq. to 3.0 eq. of a base, at a temperature of 150°C to 350°C, under the influence of a transition metal-containing heterogeneous catalyst. A better yield at lower temperatures is achieved.
- -
-
Page/Page column 10; 11
(2015/03/16)
-
- A high-throughput screening method for determining the substrate scope of nitrilases
-
Nitrile compounds are intermediates in the synthesis of pharmaceuticals such as atorvastatin. We have developed a chromogenic reagent to screen for nitrilase activity as an alternative to Nessler's reagent. It produces a semi-quantifiable blue colour and hydrolysis of 38 nitrile substrates by 23 nitrilases as cell-free extracts has been shown. This journal is
- Black, Gary W.,Brown, Nicola L.,Perry, Justin J. B.,Randall, P. David,Turnbull, Graeme,Zhang, Meng
-
supporting information
p. 2660 - 2662
(2015/03/05)
-
- Rhodium(iii)-catalyzed C-H allylation of electron-deficient alkenes with allyl acetates
-
Rhodium-catalyzed C-H allylation of acrylamides with allyl acetates is reported. The use of weakly coordinating directing group resulted in high reaction efficiency, broad functionality tolerance and excellent γ-selectivity, which opens a new synthetic pathway for the access of 1,4-diene skeletons.
- Feng, Chao,Feng, Daming,Loh, Teck-Peng
-
supporting information
p. 342 - 345
(2015/01/09)
-
