Carbon monoxide high pressure

Exposure of the Baylis-Hillman adduct 178 to a high-pressure carbon monoxide atmosphere in the presence of a cyclopentadienyliron dicarbonyl dimer (Fp2) catalyst unexpectedly gives small quantities of the A -formylindoline and indolecarboxylate (Equation 114) <2003T747>. 

This mode of reaction was substantiated by further investigations of cobalt carbonyl with nitrogen (137, 229) and oxygen (229, 237) bases. With high-pressure carbon monoxide (201) cobalt carbonyl appeared to incorporate an extra molecule of carbon monoxide to form, most probably, the penta-carbonylcobalt carbonylcobaltate, in line with base reactions. 

Eq. 4.54 shows the reaction of n-heptanol (151) with Pb(OAc)4 under high-pressured carbon monoxide with an autoclave to generate the corresponding 8-lactone (152). This reaction proceeds through the formation of an oxygen-centered radical by the reaction of alcohol (151) with Pb(OAc)4,1,5-H shift, reaction with carbon monoxide to form an acyl radical, oxidation of the acyl radical with Pb(OAc)4, and finally, polar cyclization to provide 8-lactone [142-146]. This reaction can be used for primary and secondary alcohols, while (3-cleavage reaction of the formed alkoxyl radicals derived from tertiary alcohols occurs. 

High-pressure carbon monoxide (10 MPa) is dangerous and the equipment must be constructed with special care. 

The preparation of single-walled nanotubes succeeds more easily by the so-called HiPCo-process that was published for the first time in 1998. The name is deduced from high-pressure carbon monoxide and signifies a crucial aspect of the method Here the carbon source is not a hydrocarbon, but carbon monoxide that does not suffer pyrolysis at the relevant temperatures. The formation of carbon material is based on the Boudouard equilibrium (3.9) ... 

Other procedures for the synthesis of CNTs use a gas phase for introducing the catalyst, in which both the catalyst and the hydrocarbon gas are fed into a furnace, followed by a catalytic reaction in the gas phase. The method is suitable for large-scale synthesis, because nanotubes are free from catalytic supports and the reaction can be operated continuously. A high-pressure carbon monoxide reaction method, in which the CO gas reacts with iron pentacarbonyl to form SWNTs, has been developed [38]. SWNTs have been synthesized from a mixture of benzene and ferrocene in a hydrogen gas flow [55]. In both methods, catalyst nanoparticles are formed through thermal decomposition of organometallic compounds, such as iron pentacarbonyl and ferrocene. 

In the same line, high-Pressure carbon monoxide (HiPco) SWCNTs were functionalized along their sidewalls with hydroxyalkyl groups using a radical addition scheme.These moieties were found to be active in the polymerization of acrylic acid from the surface of the nanotubes by a redox radical mechanism. In Figure 9.4 (left-hand panel) the Raman response of pristine, ethanol-treated and polymer-modified samples is illustrated. Compared with... 

CNTs can be obtained by electric arc discharge, laser ablation, high-pressure carbon monoxide, and catalyzed chemical vapor deposition. The multiple synthesis methods for CNTs are outside the scope of this chapter and had been extensively reviewed elsewhere [26-28]. The first three methods produce a large amount of by-products such as graphitic debris, metallic NPs, and fullerenes. On the contrary, CNTs obtained by chemical vapor deposition are highly crystalline and have low defect densities, although a minimal amount of amorphous content and NPs is present [27]. 

Blocky VA/AA copolymer (Fig. 4.6.5) was sonicated with high-pressure carbon monoxide based single-walled carbon nanombes (HiPco SWCNT) in THF (Caneba... 

CNTs can be made by means of arc-discharge, laser ablation, high pressure carbon monoxide decomposition (HiPCO), and chemical vapor decomposition (CVD) processes. The HiPCO process delivers high quality SWCNTs but the upscaling is difficult. Arc-discharge, laser ablation and CVD systems are currently used to produce SWCNTs as well as MWCNTs in laboratory scales. However, until now only CVD processes have been upscaled successfully to produce MWCNTs in commercially relevant amounts. For this purpose the synthesis is usually performed in fluidized beds [10-12]. Currently (2011), industrial grades of MWCNTs can be purchased for less than 130 USD/kg. 

While both SWNT and MWNT existed in small quantities from the first wood fires at the dawn of Earth s history, their discovery and methods of preparation are only recent, as described above. Briefly, some synthetic methods include nickel catalyzed pyrolysis of methane at bOO C (64) for MWNT, and the so-called HiPCO (high pressure carbon monoxide) process for SWNT.This latter involves thermal decomposition of iron pentacarbonyl in a flow of CO at 800-1200°C (65). 

CNT s are fabricated by a number of different methods including arc discharge, CVD, high pressure carbon monoxide (HiPco), and laser ablation. Laser ablation mainly produces SWNTs but is more expensive than the CVD and arc discharge techniques [51]. Alternatively, CVD methodology allows... 

Fe(CO)s is a stable compound. It does not react with air at room temperatures and under light irradiation Fc2(CO)9 gradually increases. Fe(CO)5 [Pg.307]

Acronyms and variables cold crystalhzation (CC) cobalt molybdenum catalyst (CoMoCAT) chemical vapor deposition (CVD) dichlorobenzene (DCB) high-pressure carbon monoxide (HiPCO) isotactic polypropylene (iPP) melt crystalhzation (MC) melt flow index (MFl) poly( -caprolactone) (PCL) polydispersity index (PDD polyethylene (PE) polyethylene oxide (PEO) poly (ethylene-propylene-diene) [P(E-PP-diene)] poly(ethylene 2,6-naphthalate) (PEN) poly(ethylene terephthalate (PET) poly(L-lactic acid) (PLLA) poly(trimethylene terephthalate (PTMT) poly(vinyl alcohol) (PVA) 1,1,2,2-tetrachloroethane (TCE) tetrahydrofuran (THE) weight-average molecular weight = ] number-average molecular weight Avrami exponent for neat polymer = Avrami exponent for CNT composite = Avrami rate constant for neat polymer = Avrami exponent for composite = neat polymer crystalhzation... 

SWNTs for the flammability study of PMMA-SWNT nanocomposites were synthesized by the high-pressure carbon monoxide method (HiPCO) and the coagulation method was used to produce PMMA-SWNT nanocomposites in... 

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