Carbon under high pressure

S. I. Hirano, K. Shimono, and S. Naka, Diamond formation from glassy carbon under high pressure and temperature conditions. J. Mater. Sci., 17, 1856-1862, 1982. 

Most of the diamonds used around the world have been mined from the Earth s crust. However, artificial diamonds can be made by heating other forms of carbon under high pressure. Artificial diamonds are too small to be used for jewellery but they can be used for drill tips. 

Under high pressures and temperatures, iodine reacts with oxygen to form iodine pentoxide [12029-98-0] (44). The reaction of iodine with carbon monoxide under acidic conditions is catalyzed by palladium salts (45). Phosphorous vapor and iodine react to form phosphoms trHodide [13455-01 -17, PI (46). 

Fischer-Tropsch Waxes. Polymethylene wax [8002-74-2] production is based on the Fischer-Tropsch synthesis, which is basicaHy the polymerisation of carbon monoxide under high pressure and over special catalysts to produce hydrocarbons (see Fuels, synthetic-liquid fuels). 

Low Oxidation State Chromium Compounds. Cr(0) compounds are TT-bonded complexes that require electron-rich donor species such as CO and C H to stabilize the low oxidation state. A direct synthesis of Cr(CO)g, from the metal and CO, is not possible. Normally, the preparation requires an anhydrous Cr(III) salt, a reducing agent, an arene compound, carbon monoxide that may or may not be under high pressure, and an inert atmosphere (see Carbonyls). 

This will generally be tr-ue as we proceed to look at other alkanes as the number of carbon atoms increases, so does the boiling point. All the alkanes with four car bons or less are gases at room temperature and atmospheric pressure. With the highest boiling point of the three, propane is the easiest one to liquefy. We are all faniliar- with propane tanks. These are steel containers in which a propane-rich mixture of hydrocar bons called liquefied petroleum gas (LEG) is maintained in a liquid state under high pressure as a convenient clean-burning fuel. 

Bhattachaijee et al. [98] reported that nitrile rubber can be selectively hydroformylated in the presence of RhH(CO)(PPh3)3 and RhCl(CO)(PPh3)2 under high pressure of carbon monoxide and hydrogen. They found that RhH(CO)(PPh3)3 was more efficient than RhCl(CO)(PPh3)2. However, both catalysts offered se-... 

Cycloaddition reactions of (E)-l-acetoxybutadiene (18a) and (E)-l-methoxy-butadiene (18b) with the acrylic and crotonic dienophiles 19 were studied under high pressure conditions [9] (Table 5.1). Whereas the reactions of 18a with acrylic dienophiles regioselectively and stereoselectively afforded only ortho-enJo-adducts 20 in fair to good yields, those with crotonic dienophiles did not work. Similar results were obtained in the reactions with diene 18b. The loss of reactivity of the crotonic dienophiles has been ascribed to the combination of steric and electronic effects due to the methyl group at the )S-carbon of the olefinic double bond. 

Carbon dioxide can be liquefied under high pressure (supercritical CO2). Several reactions have been done using supercritical CO2 as the medium, but special apparatus is required. This medium offers many advantages," and some disadvantages, but is an interesting new area of research. 

Products Obtained by Electrochemical Reduction of Carbon Dioxide under High Pressure of 10 kg/cm2 Gagea... 

H. Sumiya and T. Irifune, Hardness and Deformation Microstructures of Nanopolycrystalline Diamonds Synthesized from Various Carbons under Hig Pressure and High Temperature , J. Mater. Res., 22 (8), 2345 (2007). 

U.D. Venkateswaran, A.M. Rao, E. Richter, M. Menon, A. Rinzler, R.E. Smalley, P.C. Eklund, Probing the single-wall carbon nanotube bundle Raman scattering under high pressure. Phys. Rev. B 59, 10928-10934 (1999). 

A new heterocyclic system, 3 ,4-dihydro-3//-benzo[4,5]imidazo[l,2-f]oxazol-l-one 462, was synthesized by reaction of 4,4-dimethyl-5-methylene-l,3-dioxolan-2-one with o-phenylenediamine in the presence of copper bromide as catalyst in carbone dioxide at 60-80 °C under high pressure (Equation 217) <1999CHC216>. 

Sugar allyltins (mentioned already in 2.2.3.) were used for the preparation of higher carbon sugars. This may be illustrated by reaction of the furano-side 99 with di-O-isopropylidene-D-arabinose performed under high pressure, which provided compound 100 (Fig. 33).43,48... 

High-pressure experiments promise to provide insight into chemical reactivity under extreme conditions. For instance, chemical equilibrium analysis of shocked hydrocarbons predicts the formation of condensed carbon and molecular hydrogen.17 Similar mechanisms are at play when detonating energetic materials form condensed carbon.10 Diamond anvil cell experiments have been used to determine the equation of state of methanol under high pressures.18 We can then use a thermodynamic model to estimate the amount of methanol formed under detonation conditions.19... 

Fullerenes are the third natural form of carbon. These have been found to exist in interstellar dust and in geological formations on Earth, but only in 1985 did Smalley, Kroto and co-workers discovered this class of carbon solids and their unusual properties [447, 448]. It has been shown that Ceo, the most common fullerene, could be transformed under high pressure into the other forms of carbon, diamond, and graphite [449] or, at moderately high pressures and temperatures, into new various metastable forms [450 53]. Ceo crystals, fullerites, have/cc structure with weak van der Waals interactions. This structure is stable at ambient temperature up to 20 GPa and at ambient pressure up to 1800 K [454, 455]. 

S.P. Chan, G. Chen, X.G. Gong, Z.F. Liu, Chemisorption of hydrogen molecules on carbon nanotubes under high pressure. Phys. Rev. Lett. 87 (2001) 20. 

Formylation of arenes using carbon monoxide and hydrogen chloride in the presence of aluminum chloride under high pressure. 

M S. Zhurko, F.V. (2006a). Formation and decomposition of ethane, propane, and carbon dioxide hydrates in silica gel mesopores under high pressure. J. Phys. Chem. B, 110 (39), 19717-19725. 

Molybdenum hexacarbonyl usually is made by treating molybdenum pen-tachloride with zinc dust in carbon monoxide under high pressure (90 to 120 atm). Also, it can be prepared by direct combination of molybdenum metal powder with carbon monoxide under pressure. 

Pyrrole and its simple derivatives do not react easily as dienes. Pyrrole itself only combines with dimethyl acetylenedicarboxylate (DMAD, dimethyl but-2-ynedicarboxylate) under high pressure and then it is by C-2 substitution. However, A-acylpyrroles, such as A-acetyl- and N- tert-butoxycarbonyl)pyrrole, do undergo Diels-AIder addition reactions. Here, internal resonance within the acyl group reduces the availability of the lone-pair electrons, formally on nitrogen, to delocalize into the ring, thus making the carbon unit more diene-like (Scheme 6.12). 

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