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Other Feedstocks—Coal, Oil Shale, and Biomass
Published in James G. Speight, Handbook of Petrochemical Processes, 2019
Other uses are in the preparation of 2-β-methoxyethyl pyridine (known as Promintic, an anthelmintic for cattle) and in the synthesis of a 2-picoline quaternary compound (Amprolium) which is used against coccidiosis in young poultry. Beta-picoline (3-picoline; 3-methylpryridine) can be oxidized to nicotinic acid, which with the amide form (nicotinamide), belongs to the vitamin B complex; both products are widely used to fortify human and animal diets. γ-Picoline (4-picoline, 4-methylpyridine) is an intermediate in the manufacture of isonicotinic acid hydrazide (Isoniazide) which is a tuberculostatic drug. The 2,6-Lutidine (2,6-dimethylpyridine) can be converted to dipicolinic acid, which is used as a stabilizer for hydrogen peroxide and peracetic acid.
Organic and Inorganic Supramolecular Catalysts
Published in Jubaraj Bikash Baruah, Principles and Advances in Supramolecular Catalysis, 2019
Conversion of water to oxygen is one of the highly sought-after reactions. The mononuclear complex [Ru(H2O)(NPM)(pic)2]2+ (NPM = 4-t-butyl-2,6-di-(1′,8′- naphthyrid-2′-yl)-pyridine, pic = 4-methylpyridine) (2.47a) is a catalyst for water splitting. The water ligand has a role in the activation process. Similar to such an observation, the complex [Ru(tda)(py)2] (tda = 2,2′:6′,2′′-terpyridine- 6,6′′-dicarboxylate, py = pyridine) 2.47b shows high catalytic activity with turnover frequency 5 × 105 sec−1 at pH 10. This complex has a free carboxylate group on the ligand. The free carboxylate group serves as activating site; it hydrogen bonds with the water molecule and brings it close to the active site. On the other hand, the sulphonate groups on the ligand of [Ru(tpy)(bpyms)(OH2)] (bpyms = 2,2′-bipyridine-5,5′-bis(methanesulfonate) 2.47c are at the appropriate location in the coordination sphere to anchor cerium (IV) hydroxide. The complex shows higher water-splitting ability in the presence of cerium (IV) ions than a complex without the cerium ion. These examples are explicit demonstrations of ligands controlling catalytic activity through supramolecular interactions (Figure 2.47).
Crystallization Basics
Published in John J. McKetta, Unit Operations Handbook, 2018
In 1962 Cosden Petroleum Co. of fered for sale 95% pure w-xyIene made by a process using a Werner-type complex to clathrate μ-xylene. The process was licensed from Union Oil Co. and the flow scheme for the process is probably similartothatdescribed in U.S.Patents2,798,103and 2,951,104andshown in Fig. 23. As depicted in this figure, a solvent is used to dissolve thecomplex, the clathrate is precipitated at a lower temperature, and theμ-xylene is recovered from the clathrate by dissolving in a solvent. In a typical version of the process, the w, p-xylene mixture is contacted with a Werner complex at 25°C. The Werner complex is prepared by adding 4 mol of μ-picoline to 1 mol of nickel dithiocyanate to yield tetra(4-methylpyridine) nickel thiocyanate. The mole ratio of this complex to p-xylene in the feed to the clathration step is about 1.12. The economics of the process is greatly affected by the method of decomposing the clathrate. During the decomposition step, conditions are adjusted to decompose the clathrate and to minimize the destruction of the Werner complex.
Effects of a triangular nanocage structure on the binding of neutral and anionic ligands to CoII and ZnII porphyrins
Published in Journal of Coordination Chemistry, 2022
P. Thomas Blackburn, Mark C. Lipke
Unless otherwise specified, commercially available chemicals and solvents were used as received from (1) Fisher: acetonitrile, pyridine (py); (2) Acros Organics: ammonium hexafluorophosphate, zinc acetate dihydrate, tetrabutylammonium hydroxide 40 wt% (1.5 M) aqueous solution; (3) Cambridge Isotopes: acetonitrile-d3 (CD3CN, D-99.8%); (4) TCI Chemicals: 4-methylpyridine (4-MePy); (5) Ambeed: 3,5-di-tert-butylbenzoic acid. (6) Alfa Aesar: 3-methylpyridine (3-MePy), 3,5-dimethylpyridine (3,5-Me2Py); (7) Accela: 4-tert-butylpyridine (4-tBuPy). Nanocages Co3-1 and Zn3-1, and porphyrins Co-2 and [tetra(N-methyl-3-pyridinium)porphyrin]·4PF6 (2) were prepared as we have previously described [34, 47]. Tetrabutylammonium benzoate ([TBA][BzO]) and 4-(4′-methoxyphenyl)pyridine (4-ArPy) were prepared following literature procedures [48, 49].
The effect of structure and isomerism on the vapor pressures of organic molecules and its potential atmospheric relevance
Published in Aerosol Science and Technology, 2019
Caroline Dang, Thomas Bannan, Petroc Shelley, Michael Priestley, Stephen D. Worrall, John Waters, Hugh Coe, Carl J. Percival, David Topping
Secondly, the effects of positional isomerism are apparent for the measured methylpyridine carboxylic acids, but effects of isomerism are poorly accounted for in most models. The Nannolal method shows changes in vapor pressure as a function of isomerism for the methylpyridine carboxylic acid isomers. Using Nannolal vapor pressure/Nannolal boiling points, predictions for 2,3/2,4/3,2, and 4,2 methylpyridine carboxylic acids follow the same trend as the KEMS subcooled vapor pressures, where 2-methylpyridine-3-carboxylic and 2-methylpyridine-4-carboxylic values are approximately a factor of 1.4 to 1.8 larger than 3-methylpyridine-2-carboxylic and 4-methylpyridine-2-carboxylic acid, respectively. This does not hold for the remaining 4,3/5,3 and 6,2 methylpyridine-carboxylic acids, however. None of the estimation methods predict a change in vapor pressures due to nitro-cresol functional group positioning, while the experimental data shows more than an order of magnitude difference in vapor pressures based on functional group positioning- for example from 2-nitro-p-cresol (5.97E-04) to 3-nitro-p-cresol (4.85E-03). The Nannoolal method has parameters to deal with ortho, meta and para isomerism in aromatic rings with two functional groups, but has no parameters to account for higher functional aromatics like those with three functional groups such as the nitrocresols studied here. This is why the Nannoolal based methods predict different vapor pressures for the cresols but not for the nitrocresols.
Synthesis and catalytic performance of 2-ferrocenylpyridine palladacycle complexes
Published in Journal of Coordination Chemistry, 2019
Ligang Yan, Limin Han, Ruijun Xie
Synthesis of the 2-ferrocenylpyridine palladacycles (1–7) were carried out under an atmosphere of purified argon using standard Schlenk techniques and monitored with thin-layer chromatography (TLC). Solvents were freshly dried and distilled. 2-FcPy, 4-FcPy, and Li2PdCl4 were prepared according to previously reported methods [25, 26]. PPh3, NaOAc, 4-iodotoluene, phenylboronic acid, pyridine, 4-phenylpyridine, 4-tert-butylpyridine, 4-methylpyridine, 4-methoxypyridine, and K3PO4 were purchased from Alfa-Aesar Chem and used as received. Column chromatographic separations and purifications were performed on 100–200 mesh silica gel. 1H, 13C, and 31P NMR spectra were recorded on an Agilent Technologies-500 MHz spectrometer. FT-IR spectra were measured on a Nexus-870 FT-IR spectrometer. Elemental analyses were carried out on an Elementarvar III-type analyzer.