Catalyst-, mixture

Digestion. 20-25 mg. of the substance whose nitrogen content is to be estimated are weighed out in a stoppered weighing-tube and then transferred to the flask L that has been previously dried in an oven at izo C. With care, the substance may be transferred directly into the bulb of the flask without any adhering to the sides. If any material sticks on the way down, the flask should be tapped gently to cause the substance to fall to the bottom. 2 G. of the catalyst mixture (32 g. of potassium sulphate, 5 g. of mercury sulphate and ig. of selenium powder, well mixed) are added and 3 ml. of A.R. cone, sulphuric acid are measured out carefully and poured into the digestion... 

When heated with acidic oxide catalysts, mixtures of butynediol with ammonia or amines give pyrroles (66) (see Pyrrole AND PYRROLE DERIVATIVES). 

The product contains 12.6% phosphoms and has an OH number in the 450 mg KOH/g range. Fyrol 6 is used to impart a permanent Class 11 E-84 flame spread rating to rigid foam for insulating walls and roofs. Particular advantages are low viscosity, stabiHty in polyol—catalyst mixtures, and outstanding humid aging resistance. Fyrol 6 is used in both spray foam, froth, pour-in-place, and slab stock. 

The second processing step, in which benzoic acid is oxidized and hydrolyzed to phenol, is carried out in two reactors in series. In the first reactor, the benzoic acid is oxidized to phenyl benzoate in the presence of air and a catalyst mixture of copper and magnesium salts. The reactor is operated at 234°C and 147 kPa gauge (1.5 kg/cm g uge). The phenyl benzoate is then hydrolyzed with steam in the second reactor to yield phenol and carbon dioxide. This occurs at 200°C and atmospheric pressure. The overall yield of phenol from benzoic acid is around 88 mol %. Figure 2 shows a simplified diagram for the toluene—benzoic acid process. 

An important aspect of this procedure is the use of latent acid catalysts, such as phenyl hydrogen maleate, phenyl trifluoracetate, and butadiene sulfone. These catalysts reduce the peak exotherm from over 200°C to 130—160°C. The resin catalyst mixture has a working life of up to several days at RT. The elevated temperature of mol ding these latent catalysts generates the corresponding acids, namely, maleic, trifluoracetic, and phenolsulfonic, which cataly2e the resole reaction. Typically, a cycle time of 1—2 min is requited for a mold temperature of - 150° C. 

Today, the air oxidation of toluene is the source of most of the world s synthetic benzaldehyde. Both vapor- and Hquid-phase air oxidation processes have been used. In the vapor-phase process, a mixture of air and toluene vapor is passed over a catalyst consisting of the oxides of uranium, molybdenum, or related metals. High temperatures and short contact times are essential to maximize yields. Small amounts of copper oxide maybe added to the catalyst mixture to reduce formation of by-product maleic anhydride. 

Dale and co-workers examined this reaction in considerable detail some years later and utilized a mixture of HF and BFj in dioxane as catalyst. They noted that this catalyst mixture was stable for months at room temperature and did not etch glass. It was useful for initiating the cyclooligomerization reaction which led to a product mixture. The composition of the mixture was apparently independent of the ethylene oxide concentration and the reaction was apparently not kinetically controlled. 

High stereoselectivity was noted with Wilkinson s catalyst in the reaction of arylalkynes with diethoxymethylsilane. Interestingly, the stereoselectivity was dependent on the order of mixing of the reagents and the catalyst. When the alkyne was added to a mixture of catalyst and silane, the Z-isomer was formed. Reversing the order and adding the silane to an alkyne-catalyst mixture led to formation of the -product.78... 

One cm3 of the reactant/product/catalyst mixture was sampled periodically during the reaction for the transmission infrared analysis (Nicolet Magna 550 Series II infrared spectrometer with a MCT detector). The concentrations of reactants and products were obtained by multiplying integrated absorbance of each species by its molar extinction coefficient. The molar extinction coefficient was determined from the slope of a calibration curve, a plot of the peak area versus the number of moles of the reagent in the IR cell. The reaction on each catalyst was repeated and the relative error for the carbamate yield measured by IR is within 5%. 

The formation of relatively ill-defined catalysts for epoxide/C02 copolymerization catalysts, arising from the treatment of ZnO with acid anhydrides or monoesters of dicarboxylic acids, has been described in a patent disclosure.968 Employing the perfluoroalkyl ester acid (342) renders the catalyst soluble in supercritical C02.969 At 110°C and 2,000 psi this catalyst mixture performs similarly to the zinc bisphenolates, producing a 96 4 ratio of polycarbonate polyether linkages, with a turnover of 440 g polymer/g [Zn] and a broad polydispersity (Mw/Mn>4). Related aluminum complexes have also been studied and (343) was found to be particularly active. However, selectivity is poor, with a ratio of 1 3.6 polycarbonate polyether.970... 

The TG analysis for pure PP proves a steep weight loss with a maximum in the DTG curve placed at 520 °C, which corresponds with the thermal degradation of this polyolefin. Fig 1 and 2 show TG analysis of PP/H-ZSM5 and PP/Ti-MCM41 catalyst mixture with 10 % catalyst content. 

Ligand to rhodium ratio is 10, catalysis performed in 13 ml of toluene using 1 ml of 1-octene as the substrate at 80 °C and 50 bar CO/H2. Samples were analysed by means of GC and GC-MS analysis. b Average turnover frequencies were calculated as (mol product)(mol catalyst)1 h 1.c 1 ml of 1-propanol added to the catalyst mixture 1 Initial turnover frequency. 1 ml of triethylamine added to the catalyst mixture. 

Verbanc (11) found that, after removal of the products and monomers from the catalyst mixture, the remaining Rh catalyst residual is inactive... 

Addition of halocarbons to alkenes in the presence of transition metals is a well-known radical reaction. Weinreb etal. have now reported an intramolecular version leading to cyclic esters or bicyclic lactones. Typical substrates are the a,a-dichloro ester 1 or the a,a-dichloro acid 2, readily available by reaction of ethyl lithiodi-chloroacetate with 5-bromo-l-pentene. When 1 is heated in benzene at 160° with a metal catalyst, mixtures of epimeric ot,w-dichloro esters 3 and 4 are obtained. The ratio and yields of 3 and 4 are dependent on the catalyst and concentration of 1, but 3 and 4 are the major products formed in the presence of Ru(II) and Fe(II) catalysts. In contrast cyclization of 2 under the same conditions gives the bicyclic y-lactone 5 in high yield. 

The active component of the catalyst mixture is a complex which gets formed between titanium trichloride and triethylaluminium. The structure of the complex may be put as follows ... 

BASF led the development of a route based on ethylene and synthesis gas. Its four step process begins with the production of propionaldehyde from ethylene, CO, and H2 using a proprietary catalyst mixture that they aren t telling anything about. Reaction with formaldehyde gives methacrolein. The last two steps are the same as above—oxidation with air yields the MAA subsequent reaction with methanol yields MMA. 

An acid-rhenium catalyst mixture acts on ( )-4-(4-hydroxyphenyl)butan-2-one oxime (44) to produce a high yield of the spiro compound (45), which then rearranges to the substituted quinoline (46)." ° The Beckmann rearrangement product (47)... 

Even in an excess of ligands capable of stabilizing low oxidation state transition metal ions in aqueous systems, one may often observe the reduction of the central ion of a catalyst complex to the metallic state. In many cases this leads to a loss of catalytic activity, however, in certain systems an active and selective catalyst mixture is formed. Such is the case when a solution of RhCU in water methanol = 1 1 is refluxed in the presence of three equivalents of TPPTS. Evaporation to dryness gives a brown solid which is an active catalyst for the hydrogenation of a wide range of olefins in aqueous solution or in two-phase reaction systems. This solid contains a mixture of Rh(I)-phosphine complexes, TPPTS oxide and colloidal rhodium. Patin and co-workers developed a preparative scale method for biphasic hydrogenation of olefins [61], some of the substrates and products are shown on Scheme 3.3. The reaction is strongly influenced by steric effects. 

Oxidative carbonylation of methane to acetic acid is one of the pursued ways to solve the fundamental problem of direct methane utilization. Partly aqueous systems with RhCU-HCl-KI catalyst mixture were applied with some success for this purpose. However, the reaction proceeds faster in acetic acid as solvent, containing only a small percentage of water [34]. 

Si02-supported neodymium-based catalyst mixtures Nd(naph)3/Al2Et3Cl3/ A1( Bu)3 (54) and Al( Bu)2H (DIBAH), instead of Al( Bu)3, were also tested as initiators for the gas-phase polymerization of 1,3-butadiene by varying the polymerization temperature, nature and feed of co-catalyst and polymerization time (Table 12.8). High ds-1,4-contents (97.8-98.9%) and activities between 400 and 2300 kg-PBD molNd h bar were observed, but the polymers displayed broad molecular weight distributions of 2 < M /M < 8 [158-160]. 

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