Carbonic acid palladium

Terephthalic acid (p-TA or TA), a raw material for polyethylene terephthalate (PET) production, is one of the most important chemicals in petrochemical industry. Crude terephthalic acid (CTA), commonly produced by homogeneous liquid phase p-xylene oxidation, contains impurities such as 4-carboxybenzaldehyde (4-CBA, 2000-5000 ppm) and several colored polyaromatics that should be removed to obtain purified terephthalic acid (PTA). PTA is manufactured by hydropurification of CTA over carbon supported palladium catalyst (Pd/C) in current industry [1]. 

Another example is the palladium catalyzed allylic substitution of 3-phenyl-2-propenyl-carbonic acid methyl ester to yield iV-(3-phenyl-2-propenyl)morpho-line reported by Reetz, Kragl and co-workers. This reaction was performed in the presence of phosphino-terminated amine dendrimers [17, 18] loaded with Pd11 cations as shown in Scheme 10. For this particular dendrimer with a molecular weight of 10 212 g/mol, a retention of 0.999 per residence time [35] was estimated in a membrane reactor with a SELRO MPF-50 membrane. It must be noted that a very high retention is a prerequisite for a continuous operating system, since a small leaching of the dendrimer leads to an exponential decrease in the amount... 

Formic acid, Palladium-carbon catalyst, 0418 Formic acid, Phosphorus pentaoxide, 0418 Furan-2-amidoxime, 1872... 

Two tests were used for the detection of glycolic acid the chromatropic acid test and the method whereby the glycolic acid is treated with sulfuric acid and the resulting carbon monoxide detected by phosphomolybdic acid-palladium chloride reagent (10, 12). 

The phosphomolybdic acid-palladium chloride test was used for the detection of carbon monoxide (25). 

Ammonia Hydrochloric acid Palladium on carbon Sodium hydroxide... 

Ethyl chloroformate Triethylamine Thioacetic acid Palladium on carbon Zinc... 

Acetic anhydride Oxalyl chloride Formic acid Palladium on carbon... 

Bromacetyl bromide Carbon disulfide Palladium on carbon Hydrochloric acid... 

The iodyl group (I02) is a good nucleofugue. Under mild conditions, the conversion of several iodylarenes into benzoic acids was realized in good yields, via carbonylation. Carbon monoxide was used at atmospheric pressure and 40-50°C, in aqueous sodium carbonate, with palladium catalysis [9] ... 

A modification of the Suzuki coupling reaction proved to be a clean and useful method for the preparation of monosubstituted arylferrocenes. Iodoferrocene was reacted with a series of substituted arylboronic acids in the presence of sodium carbonate and palladium acetate in aqueous ethanol at room temperature to produce a range of substituted monoarylfer-rocenes (Eq. (19)). A systematic investigation undertaken to determine the optimal reaction conditions indicated that scrupulous deoxygenation of the solvent is critical. The use of... 

These studies also revealed the formation of several other coupling products from which isomeric C9 y-lactones and isomeric octadienyl esters of nonatriene-carbonic acid have been isolated. A number of more and less effective variations of phosphine-palladium-based catalysts were reported [3e, f, 4, 8]. Efforts to establish an enantioselective catalytic synthesis of the 5-lactone by use of chiral coligands, remained unsuccessful however [8e, f]. 

Fonnic acid, Palladium-carbon catalyst, 0418 t Hydrogen (Gas), Acetylene, Ethylene, 4453 t Hydrogen (Gas), Catalysts, Vegetable oils, 4453 t Hydrogen (Gas), Ethylene. Nickel catalyst, 4453 t Hydrogen (Gas), Palladium, 2-Propanol, 4453... 

Asymmetric alkylations can be performed in the presence of catalytic amounts of chiral phase transfer catalysts or through the intermediacy of 7t-allyl-palladium complexes bearing chiral ligands. Both methods normally require relatively acidic carbon acids (pKa 5 17) such as (3-diketones, P-keto- or cyanoesters or malonic acid derivatives. 

A new development is biphasic hydrogenation using solvent-stabilized colloid (SSCs) catalysts [39-41]. Palladium colloid systems, especially, were proven to give high reactivity and selectivity. Best solvents are dimethylformamide and particularly the two cyclic carbonic acid esters, ethylene carbonate and 1,2-propene carbonate. In these solvents sodium tetrachloropalladate - stabilized by a sodium carbonate buffer - is reduced with hydrogen to yield the solvent-stabilized palladium colloid. Transmission electron microscopy of the palladium colloid demonstrates that the colloid particles are spherical with an average diameter of 4 nm. 

The propene carbonate-stabilized palladium colloid is an excellent catalyst for the hydrogenation of a great number of different fatty acids, fatty esters, and triglycerides. Table 2 gives a survey of results with sunflower, palm-kernel and rapeseed oils, acids, and esters. The yield of C18 1 products after hydrogenation is in the range of 86-93%. In all examples the reaction time is very short. 

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