638-32-4Relevant articles and documents
Cp? versus Bis-carbonyl iridium precursors as CH oxidation precatalysts
Huang, Daria L.,Vinyard, David J.,Blakemore, James D.,Hashmi, Sara M.,Crabtree, Robert H.
, p. 199 - 206 (2017/11/27)
We previously reported a dimeric IrIV-oxo species as the active water oxidation catalyst formed from a Cp?Ir(pyalc)Cl {pyalc = 2-(2′-pyridyl)-2-propanoate} precursor, where the Cp? is lost to oxidative degradation during catalyst activation; this system can also oxidize unactivated CH bonds. We now show that the same Cp?Ir(pyalc)Cl precursor leads to two distinct active catalysts for CH oxidation. In the presence of external CH substrate, the Cp? remains ligated to the Ir center during catalysis; the active species-likely a highvalent Cp?Ir(pyalc) species-will oxidize the substrate instead of its own Cp?. If there is no external CH substrate in the reaction mixture, the Cp? will be oxidized and lost, and the active species is then an iridium-μ-oxo dimer. Additionally, the recently reported Ir(CO)2(pyalc) water oxidation precatalyst is now found to be an efficient, stereoretentive CH oxidation precursor. We compare the reactivity of Ir(CO)2(pyalc) and Cp?Ir(pyalc)Cl precursors and show that both can lose their placeholder ligands, CO or Cp?, to form substantially similar dimeric IrIV-oxo catalyst resting states. The more efficient activation of the bis-carbonyl precursor makes it less inhibited by obligatory byproducts formed from Cp? degradation, and therefore the dicarbonyl is our preferred precatalyst for oxidation catalysis.
PROCESSES FOR THE PRODUCTION OF HYDROGENATED PRODUCTS
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Page/Page column 7, (2011/10/13)
A process for making a hydrogenated product includes providing a clarified DAS-containing fermentation broth; distilling the broth under super atmospheric pressure at a temperature of >100° C. to about 300° C. to form an overhead that includes water and ammonia, and a liquid bottoms that includes SA, and at least about 20 wt % water; cooling the bottoms to a temperature sufficient to cause the bottoms to separate into a liquid portion in contact with a solid portion that is substantially pure SA; separating the solid portion from the liquid portion; recovering the solid portion; hydrogenating the solid portion in the presence of at least one hydrogenation catalyst to produce the hydrogenated product including at least one of THF, GBL or BDO; and recovering the hydrogenated product.
METHOD FOR PRODUCING ORGANIC ACID
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Page/Page column 35-36, (2008/06/13)
A novel method is provided whereby a free organic acid can be produced particularly from an ammonium salt of an organic acid having a high melting point obtainable by bioconversion of a carbon source in the presence of a neutralizing agent, efficiently at a low cost, and the used material for reaction and a byproduct can be recycled for reuse without being disposed. An ammonium salt of organic acid A such as a dicarboxylic acid, a tricarboxylic acid or an amino acid is subjected to reactive crystallization by means of acid B such as a monocarboxylic acid satisfying the following formula (1), to separate free organic acid A in solid form:pKa(A) ≦ pKa(B) where pKa(A) and pKa(B) represent ionization indices of organic acid A and acid B, respectively, provided that when they have plural values, they represent the minimum pKa among them. The crystallization mother liquor after precipitating and separating organic acid A is, after separating acid B and then an ammonium salt of acid B, recycled for use in the reactive crystallization step. The ammonium salt of acid B is decomposed into acid B and ammonia, which are recycled for use in the reactive crystallization step and as a neutralizing agent in the bioconversion step, respectively.
