Promotors

The catalyst of choice is cobalt iodide with various promotors from Group 15 elements. The process is mn at 140—200°C, 28—41 MPa (4,000—6,000 psi), and gives an 88% conversion with 90% selectively to acetaldehyde. Neither of these acetaldehyde syntheses have been commercialized. 

Reppe s work also resulted in the high pressure route which was estabUshed by BASF at Ludwigshafen in 1956. In this process, acetylene, carbon monoxide, water, and a nickel catalyst react at about 200°C and 13.9 MPa (2016 psi) to give acryUc acid. Safety problems caused by handling of acetylene are alleviated by the use of tetrahydrofuran as an inert solvent. In this process, the catalyst is a mixture of nickel bromide with a cupric bromide promotor. The hquid reactor effluent is degassed and extracted. The acryUc acid is obtained by distillation of the extract and subsequendy esterified to the desked acryhc ester. The BASF process gives acryhc acid, whereas the Rohm and Haas process provides the esters dkecdy. 

Fluorinated Acids. This class of compounds is characterized by the strength of the fluorocarbon acids, eg, CF COOH, approaching that of mineral acids. This property results from the strong inductive effect of fluorine and is markedly less when the fluorocarbon group is moved away from the carbonyl group. Generally, their reactions are similar to organic acids and they find apphcations, particularly trifluoroacetic acid [76-05-1] and its anhydride [407-25-0] as promotors in the preparation of esters and ketones and in nitration reactions. 

Many human diseases are caused when certain proteins are either over- or underexpressed. Eor example, breast cancer can be induced by overexpressing certain cellular oncogenes within mammary tissue. To study the disease, researchers produce a line of transgenic mice that synthesize an abnormal amount of the same protein. This leads to symptoms of the disease in mice that are similar to what is found in humans. A protein can be overexpressed by inserting a DNA constmct with a strong promotor. Conversely, underexpression of a protein can be achieved by inserting a DNA constmct that makes antisense RNA. This latter blocks protein synthesis because the antisense RNA binds and inactivates the sense mRNA that codes for the protein. Once a line of mice is developed, treatments are studied in mice before these therapies are appHed to humans. 

Mocimycin has been chemically converted to aurodox by protection of the 4-hydroxy group at the pyridone moiety as the benzoylformate, followed by /V-methylation and hydrolytic removal of the protective group (1,55). Whereas aurodox esters are active growth promotors in animals, goldinamines that are A/-acylated by acids other than goldinonic acid, such as acetic, benzoic, or arylsulfonic acids, lack useful antimicrobial or growth-promoting activity (1). 

The manner and rate of decomposition of hypohalous acids (and hypohalite ions) in solution are much influenced by the concentration, pH and temperature of the solutions, by the presence or absence of salts which can act as catalysts, promotors or activators, and by light quanta. The main competing modes of decomposition are ... 

The mechanism of the carhonylation reaction is thought to involve a frrst-step oxidative addition of the methyl iodide promotor to the Rh(I) complex, followed hy a carhonyl cis insersion step ... 

The final step is the reaction hetween acetyl iodide and methyl alcohol, yielding acetic acid and the promotor ... 

The catalyst is a cobalt carbonyl that is prepared in situ from cobaltous hydroxide, and nonylpyridine is the promotor. Oxidation of the aldehyde produces 3-hydroxypropionic acid. 1,3-Propanediol and 3-hydroxypropi-onic acid could also be produced from acrolein (Chaper 8). ... 

Similar 2,3-adducts form with chlorine or bromine in carbon tetrachloride when the reactions are carried out with an iodine promotor and in the presence of light [57FES930 60LA(631)194], More polar solvents... 

BID is a member oftheBcl-2 gene family, which encode proteins that function either to promote apoptosis or to inhibit apoptosis as in the proteins derived from Bcl-2. These proteins can exist as monomers or they can dimerize. For example, if two promoting Bcl-2 family proteins dimerize then apoptosis will be greatly enhanced. Conversely, if dimerization of an inhibitory and promotor protein occurs, then the effects are cancelled out. The Bcl-2 family of proteins are localized to the outer mitochondrial or outer nuclear membranes. 

It has been used to some extent as an ignition promotor for Diesel fuels, in insecticides, fungicides, as an accelerator in rubber vulcanization, and as an indicator in acid titrations (Refs 10 11)... 

H.-H. Hildenbrand, and H.-G. Lintz, Solid electrolyte potentiometry aided study of the influence of promotors on the phase transitions in copper-oxide catalysts under working conditions, Catalysis Today 9, 153-160 (1991). 

Studies on Trifluoroacetic Acid. Part I. Trifluoroacetic Anhydride as a Promotor of Ester Formation between Hydroxy-Compounds and Carboxylic Acids, E. J. Bourne, M. Stacey, J. C. Tatlow, and J. M. Tedder, J. Chem. Soc., (1949) 2976-2979. 

CATALYST PROMOTOR TEMP. °C PRESSURE (bar) CONV./SEL. (%) ADVANTAGE DISADVANTAGE... 

Scheme 26 Synthesis of 2-aikyl-4-halo-1 -tosyl-1,2,5,6-tetrahydropyridines from A-tosyl homopropargyl amine and aldehydes using FeX3 as promotor...

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