127-00-4Relevant articles and documents
Influence of the metal (Al, Cr, and Co) and substituents of the porphyrin in controlling reactions involved in copolymerization of propylene oxide and carbon dioxide by porphyrin metal(III) complexes. 3. Cobalt chemistry
Chatterjee, Chandrani,Chisholm, Malcolm H.,El-Khaldy, Adnan,McIntosh, Ruaraidh D.,Miller, Jeffrey T.,Wu, Tianpin
, p. 4547 - 4553 (2013)
A series of cobalt(III) complexes LCoX, where L = 5,10,15,20- tetraphenylporphyrin (TPP), 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (TFPP), and 2,3,7,8,12,13,17,18-octaethylporphyirn (OEP) and X = Cl or acetate, has been investigated for homopolymerization of propylene oxide (PO) and copolymerization of PO and CO2 to yield polypropylene oxide (PPO) and polypropylene carbonate (PPC) or propylene carbonate (PC), respectively. These reactions were carried out both with and without the presence of a cocatalyst, namely, 4-dimethylaminopyridine (DMAP) or PPN+Cl- (bis(triphenylphosphine)iminium chloride). The PO/CO2 copolymerization process is notably faster than PO homopolymerization. With ionic PPN+Cl- cocatalyst the TPPCoOAc catalyst system grows two chains per Co center and the presence of excess [Cl-] facilitates formation of PC by two different backbiting mechanisms during copolymerization. Formation of PPC is dependent on both [Cl-] and the CO2 pressure employed (1-50 bar). TPPCoCl and PO react to form TPPCo(II) and ClCH2CH(Me)OH, while with DMAP, TPPCoCl yields TPPCo(DMAP)2+Cl-. The reactions and their polymers and other products have been monitored by various methods including react-IR, FT-IR, GPC, ESI, MALDI TOF, EXAFS, and NMR (1H, 13C{1H}) spectroscopy. Notable differences are seen in these reactions with previous studies of (porphyrin)M(III) complexes (M = Al, Cr) and of the (salen)M(III) complexes where M = Cr, Co.
Lipase-mediated partial resolution of 1,2-diol and 2-alkanol derivatives: Towards chiral building-blocks for pheromone synthesis
Izquierdo, Isidoro,Plaza, Maria T.,Rodriguez, Miguel,Tamayo, Juan
, p. 1749 - 1756 (2000)
1,2-Propanediol 5, 1-chloro-2-propanol 8 and its related 2-O-acetate 9 were partially resolved by chemoenzymatic acetylation and deacetylation, in the presence of Pseudomonas fluorescens lipase (Amano P.; PFL), to (R)-(-)-1- acetoxy-2-propanol 6, (R)-(+)-2-acetoxy-1-chloropropane 9 and (R)-(-)-1- chloro-2-propanol 8, respectively. On the other hand, treatment of (2RS)-2 with vinyl acetate in ether and Chirazyme L-2 gave 2-O-acetyl-1,3,4- trideoxy-5,6:7,8-di-O-isopropylidene-β-D-manno-non-5-ulo-5,9-pyranose 1 and 1,3,4-trideoxy-5,6:7,8-di-O-isopropylidene-β-D-gluco-non-5-ulo-5,9-pyranose 11, respectively. Compound 10 was subsequently deacylated to 12. Both alcohols 11 and 12 were treated with Me2CO/H+ to cause their rearrangement to (2S,5R,8R,9R,10S)-10-hydroxy-8,9-isopropylidenedioxy-2-methyl-1,6- dioxaspiro[4.5]decane 3 and its (2R)-epimer 4, which closely matched the skeleton of the odour bouquet minor components of Paravespula vulgaris (L.). (C) 2000 Elsevier Science Ltd.
Primary Alcohols via Nickel Pentacarboxycyclopentadienyl Diamide Catalyzed Hydrosilylation of Terminal Epoxides
Lambert, Tristan H.,Steiniger, Keri A.
supporting information, p. 8013 - 8017 (2021/10/25)
The efficient and regioselective hydrosilylation of epoxides co-catalyzed by a pentacarboxycyclopentadienyl (PCCP) diamide nickel complex and Lewis acid is reported. This method allows for the reductive opening of terminal, monosubstituted epoxides to form unbranched, primary alcohols. A range of substrates including both terminal and nonterminal epoxides are shown to work, and a mechanistic rationale is provided. This work represents the first use of a PCCP derivative as a ligand for transition-metal catalysis.
Hydrogen-Catalyzed Acid Transformation for the Hydration of Alkenes and Epoxy Alkanes over Co-N Frustrated Lewis Pair Surfaces
Deng, Qiang,Deng, Shuguang,Gao, Ruijie,Li, Xiang,Tsang, Shik Chi Edman,Wang, Jun,Zeng, Zheling,Zou, Ji-Jun
, p. 21294 - 21301 (2021/12/17)
Hydrogen (H2) is widely used as a reductant for many hydrogenation reactions; however, it has not been recognized as a catalyst for the acid transformation of active sites on solid surface. Here, we report the H2-promoted hydration of alkenes (such as styrenes and cyclic alkenes) and epoxy alkanes over single-atom Co-dispersed nitrogen-doped carbon (Co-NC) via a transformation mechanism of acid-base sites. Specifically, the specific catalytic activity and selectivity of Co-NC are superior to those of classical solid acids (acidic zeolites and resins) per micromole of acid, whereas the hydration catalysis does not take place under a nitrogen atmosphere. Detailed investigations indicate that H2 can be heterolyzed on the Co-N bond to form Hδ-Co-N-Hδ+ and then be converted into OHδ-Co-N-Hδ+ accompanied by H2 generation via a H2O-mediated path, which significantly reduces the activation energy for hydration reactions. This work not only provides a novel catalytic method for hydration reactions but also removes the conceptual barriers between hydrogenation and acid catalysis.
One-Pot Biocatalytic Double Oxidation of α-Isophorone for the Synthesis of Ketoisophorone
Tavanti, Michele,Parmeggiani, Fabio,Castellanos, J. Rubén Gómez,Mattevi, Andrea,Turner, Nicholas J.
, p. 3338 - 3348 (2017/09/13)
The chemical synthesis of ketoisophorone, a valuable building block of vitamins and pharmaceuticals, suffers from several drawbacks in terms of reaction conditions and selectivity. Herein, the first biocatalytic one-pot double oxidation of the readily available α-isophorone to ketoisophorone is described. Variants of the self-sufficient P450cam-RhFRed with improved activity have been identified to perform the first step of the designed cascade (regio- and enantioselective allylic oxidation of α-isophorone to 4-hydroxy-α-isophorone). For the second step, the screening of a broad panel of alcohol dehydrogenases (ADHs) led to the identification of Cm-ADH10 from Candida magnoliae. The crystal structure of Cm-ADH10 was solved and docking experiments confirmed the preferred position and geometry of the substrate for catalysis. The synthesis of ketoisophorone was demonstrated both as a one-pot two-step process and as a cascade process employing designer cells co-expressing the two biocatalysts, with a productivity of up to 1.4 g L?1 d?1.
Method for preparing halogen propanol and epoxypropane
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Paragraph 0086; 0087-0099; 0104; 0105; 0112-0115; 0118-0130, (2017/05/19)
The invention provides a method for preparing halogen propanol. The method comprises the following steps (1) halogen alcoholization: adding halogen hydride, H2O2, propylene and an HTS molecular sieve into a reaction device, and carrying out halogen alcoholization reaction to obtain the halogen propanol. The invention also provides a method for preparing epoxypropane with a halogenohydrin method. The method comprises the following steps: (1) halogen alcoholization: adding halogen hydride, H2O2, propylene and an HTS molecular sieve into the reaction device, and carrying out the halogen alcoholization reaction to obtain halogen propanol; (2) saponification: carrying out saponification reaction on halogen propanol and a hydroxide of alkali metal in step (1), and separating to obtain the epoxypropane and alkali halide metal salt; optionally (3) electroosmosis: carrying out bipolar membrane electroosmosis on the alkali halide metal salt obtained in step (2) to obtain the hydroxide of alkali metal and the halogen hydride. According to the methods, the halogen propanol or the epoxypropane can be prepared at extremely high selectivity and yield, and the discharging of waste water and waste residues can be drastically lowered.
PROCESS FOR HYDROGENATING DICHLOROISOPROPYL ETHER
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Page/Page column 5, (2016/04/20)
Convert dichloroisopropyl ether into a halogenated derivative by contacting the dichloroisopropyl ether with a source of hydrogen and a select heterogeneous hydrogenation catalyst under process conditions selected from a combination of a temperature within a range of from 50 degrees centigrade (oC) to 350 oC, a pressure within a range of from atmospheric pressure (0.1 megapascals) to 1000 pounds per square inch (6.9 MPa), a liquid feed volume flow to catalyst mass ratio between 0.5 and 10 L/Kg*h and a volume hydrogen / volume liquid ratio between 100 and 5000 ml gas/ ml liquid. The halogenated derivative is at least one of 1-chloro-2-propanol and 1,2-dichloropropane 1, and glycerin monochlorohydrin.
Facile Protocol for Catalytic Frustrated Lewis Pair Hydrogenation and Reductive Deoxygenation of Ketones and Aldehydes
Mahdi, Tayseer,Stephan, Douglas W.
supporting information, p. 8511 - 8514 (2015/11/27)
A series of ketones and aldehydes are reduced in toluene under H2 in the presence of 5 mol % B(C6F5)3 and either cyclodextrin or molecular sieves affording a facile metal-free protocol for reduction to alcohols. Similar treatment of aryl ketones resulted in metal-free deoxygenation yielding aromatic hydrocarbons.
Enabling catalytic ketone hydrogenation by frustrated lewis pairs
Mahdi, Tayseer,Stephan, Douglas W.
supporting information, p. 15809 - 15812 (2015/02/19)
Hydrogenation of alkyl and aryl ketones using H2 is catalytically achieved in 18 examples using 5 mol % B(C6F5)3 in an ethereal solvent. In these cases the borane and ether behave as a frustrated Lewis pair to activate H2 and effect the reduction.
A convenient method for producing mono- and dichlorohydrins from glycerol
Giomi, Donatella,Malavolti, Marino,Piccolo, Oreste,Salvini, Antonella,Brandi, Alberto
, p. 46319 - 46326 (2015/02/19)
A new method for the transformation of glycerol into mono- and dichlorohydrins has been studied. With trimethylchlorosilane as chlorinating agent and acetic acid as catalyst, mono- and dichlorohydrins have been obtained in high yields and selectivity. In fact, under different reaction conditions, the synthesis of α-monochlorohydrin (3-chloropropan-1,2-diol) or α,γ-dichlorohydrin (1,3-dichloropropan-2-ol) as predominant product has been achieved. This process was also exploited for the valorisation of the crude mixture of glycerol and monochlorohydrin (glyceric mixture), a by-product from an earlier BioDiesel production. A reaction mechanism has been proposed based on investigations on the chlorination of different alcohols.
