Toluene catalysts

It follows that each molecule of HD formed corresponds to a molecule of metal hydride. Measurements of HD showed that one percent of metal hydride was present as an impurity in the Zr (benzyl)4 solution in toluene catalyst. On adding styrene monomer the hydride did not disappear from the reaction mixture, but progressively increased as the polymerization proceeded. It was estimated that if the hydride had the empirical formula (CeH6CH2) 3ZrH] , the amount formed corresponded to one molecule per chain. The persistence of this hydride in solution probably results from dimerization giving species of the type (XXVIII). 

Table VII. Effect of organoaluminum compounds on catalyst activity. Polymerization conditions molar ratio butadiene, propylene is 1.1 monomer concentration, 20 wt % in toluene catalyst, 0.8 mmol VO[OCH2C(CH3)3]2Cl phm, 5 mmol Al compound phm reaction time, 4 h and —45°C. Data from Ref. 19.

Figure 5. Variation of trans-7,4 content with the molar ratio of monomer to initiator. Conditions solvent, toluene catalyst, Ba[(t-BuO)gx (OH)x] and n-BuLi.

Fig. 22. Molecular weight of polybutene-1 [128]. Temp., 0°C solvent, toluene. Catalyst (a) S-TiClj/BeEtz (b) e-TiCls/AlEtjCl (c) S-TiCls/AlEtjI.

Figure 3.13 Kinetic curves of the phenyl isocyanate reaction with oligo-polyols having various primary hydroxyl contents. [Phenyl isocyanate] = [OH] = 0.5 mol/l. Solvent toluene Catalyst triethylamine Temperature 30 °C...

Common impurities include those formed in reformate fuel streams (carbon oxides (COx), methane (CH4), hydrogen sulfide (H2S), and ammonia (NH3)), pollutants found in air (sulfur oxides (SOJ, nitrogen oxides (NOJ, ammonia (NH3), and organic compounds (propane, benzene, toluene)), catalyst fines carryover, rust from piping, salts, and dust. Impurities may adsorb onto the Pt surface (CO, H2S, SO, and CP), carbon support (H2S and SOJ, or gas diffusion layers (salts, dust, and organic compounds), and adsorb into the ionomer (silica, cations (M+), NH4" ), or simply plug up the flow passages. 

Method of synthesis - polyol(s) are dried by azeotropic distllatlon (e.g., with toluene), catalyst Is added followed by addition of Isocyanate Ojha, U Kulkarni, P Faust, R, Polymer, 50, 3448-57, 2009. 

The reductive coupling of phthalimides with ketones and aldehydes in THF by low-valent titanium generated from Zn-TiC gave 3-hydroxy-3-(l-hydroxyaIkyl)-isoindolin-l-ones as two-electron reduced products and alkyhdene-isoindolin-l-ones as four-electron reduced products. These could be obtained selectively by controlling the reaction conditions. The geometric ratios of the alkylideneisoindolin-l-ones obtained from phthalimides and aldehydes could be increased by reflux in PPTS/ toluene (catalyst). In particular, the Z-isomers of A-unsubstituted alkylideneisoindolin-l-ones could be obtained exclusively. 

It was first described in 1608 when it was sublimed out of gum benzoin. It also occurs in many other natural resins. Benzoic acid is manufactured by the air oxidation of toluene in the liquid phase at 150°C and 4-6 atm. in the presence of a cobalt catalyst by the partial decarboxylation of phthalic anhydride in either the liquid or vapour phase in the presence of water by the hydrolysis of benzotrichloride (from the chlorination of toluene) in the presence of zinc chloride at 100°C. 

In the absence of catalysts, toluene when treated with chlorine (or bromine) at the boiling point, preferably with exposure to sunlight or other bright light source, undergoes halogenation in the side chain. The entrance of the first chlorine atom, for example, proceeds at a much faster rate than the entrance of the second chlorine atom so that in practice the major portion of the toluene is converted into benzyl chloride before appreciable chlorination of benzyl chloride occurs ... 

Rapid side-chain chlorination of toluene proceeds in the dark with sulphuryl chloride in the presence of dibenzoyl peroxide (0-001-0 005 mol per mol of SOjCl,) as catalyst ... 

The procedure is to pass purified hydrogen through a hot solution of the pure acid chloride in toluene or xylene in the presence of the catalyst the exit gases are bubbled through water to absorb the hydrogen chloride, and the solution is titrated with standard alkali from time to time so that the reduction may be stopped when the theoretical quantity of hydrogen chloride has been evolved. Further reduction would lead to the corresponding alcohol and hydrocarbon ... 

In the second, a trace of toluene (possibly formed by hydrolysis) is metalated by the p-tolyl-sodium to give benzyl-sodium and toluene. Since the toluene is regenerated in the reaction, a small quantity would be adequate as a sort of catalyst. 

Well, I think it s better to add a bit of H2O2 to the toluene + safrol + catalyst to prevent catalyst decomposition, for example, with 100 cc of safrol, lOcc of H2O2, and then add the rest dropwise. 

Although Pd is cheaper than Rh and Pt, it is still expensive. In Pd(0)- or Pd(ll)-catalyzed reactions, particularly in commercial processes, repeated use of Pd catalysts is required. When the products are low-boiling, they can be separated from the catalyst by distillation. The Wacker process for the production of acetaldehyde is an example. For less volatile products, there are several approaches to the economical uses of Pd catalysts. As one method, an alkyldi-phenylphosphine 9, in which the alkyl group is a polyethylene chain, is prepared as shown. The Pd complex of this phosphine has low solubility in some organic solvents such as toluene at room temperature, and is soluble at higher temperature[28]. Pd(0)-catalyzed reactions such as an allylation reaction of nucleophiles using this complex as a catalyst proceed smoothly at higher temperatures. After the reaction, the Pd complex precipitates and is recovered when the reaction mixture is cooled. 

Cycloaddition of COj with the dimethyl-substituted methylenecyclopropane 75 proceeds smoothly above 100 °C under pressure, yielding the five-membered ring lactone 76. The regiocheraistry of this reaction is different from that of above-mentioned diphenyl-substituted methylenecyclopropanes 66 and 67[61], This allylic lactone 76 is another source of trimethylenemethane when it is treated with Pd(0) catalyst coordinated by dppe in refluxing toluene to generate 77, and its reaction with aldehydes or ketones affords the 3-methylenetetrahy-drofuran derivative 78 as expected for this intermediate. Also, the lactone 76 reacts with a, /3-unsaturated carbonyl compounds. The reaction of coumarin (79) with 76 to give the chroman-2-one derivative 80 is an example[62]. 

A solution of trifluoroacetic acid in toluene was found to be advantageous for cydization of pyruvate hydrazoncs having nitro substituents[4]. p-Toluene-sulfonic acid or Amberlyst-15 in toluene has also been found to give excellent results in preparation of indole-2-carboxylale esters from pyruvate hydra-zoiies[5,6J. Acidic zeolite catalysts have been used with xylene as a solvent to convert phenylhydraziiies and ketones to indoles both in one-flask procedures and in a flow-through reactor[7]. 

The classification of hydrocarbons as aliphatic or aromatic took place m the 1860s when It was already apparent that there was something special about benzene toluene and their derivatives Their molecular formulas (benzene is CgHg toluene is C7Hj ) indicate that like alkenes and alkynes they are unsaturated and should undergo addition reac tions Under conditions m which bromine for example reacts rapidly with alkenes and alkynes however benzene proved to be inert Benzene does react with Bi2 m the pres ence of iron(III) bromide as a catalyst but even then addition isn t observed Substitu tion occurs instead ... 

An older route is based on just toluene and ammonia in the absence of air with separate catalyst regeneration (77). 

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