Casting chlorobenzene

Crude sulfur vesicants are relatively stable and stability increases with purity Distilled materials show very little decomposition on storage. Solvents such as carbon tetrachloride and chlorobenzene have been added to enhance stability of crude material. Agents can be stored in glass or steel containers, although pressure may develop in steel containers. Sulfur vesicants rapidly corrode brass and cast iron, and permeate into ordinary rubber. 

Styrene-containing polymer is completely soluble in common solvents such as CHCI3, THF, xylene, or chlorobenzene and can be spin cast as thin films that are easily cross-linked... 

Materials. PVCz (Takasago International Co. Ltd.) was purified by several reprecipitations froa benzene-methanol solution. 1-Ethylpyrene (EPy) was recrystallized and sublined in vacuo before use. PMMA was reprecipitated twice froa tetrahydrofuran solution with nethanol. PVCz films were prepared by spin-coating a 10 wtX anisole solution of the polyner on a quartz plate. PMMA and EPy were dissolved in chlorobenzene and cast on quartz or sapphire plates. 

In contrast, the chlorobenzene-cast film contains structures with horizontal dimensions of the order of only 0.1 pm. This indicates a much more uniform mixing of the constituents. Furthermore, the toluene-cast film has height variations of the order of 10 nm, whereas the chlorobenzene-cast film is extremely smooth, with height variations of the order of 1 nm. This contrast in film morphologies is mainly attributed to the fact that PCBM is more than twice as soluble in chlorobenzene as in toluene. However, the solubility of the polymer in these two solvents also changes. 

At the Griesheim Woiks the following process was applied for nitrating chlorobenzene to o- mid p- chlorodinitrobenzenes. A cast iron nitrator is charged with 6530 kg of a nitrating mixture of the composition ... 

Technical Observations. Chlorobenzene is an important intermediate in the preparation of a whole series of other compounds (see Section 6 and Tables 1 to 5). It is produced in batches of 2000 kilograms or more in cast iron kettles equipped with agitators and reflux condensers. 

Three mixtures of CO-PNNA were blended together for analysis of lithographic performance. Compositions of 20, 33, and 50% CO by weight were blended by dissolution in THF to form a 13% (total solids) solution. Cyclohexanone was added to the blend to form a 7% solution to impart proper viscosity and volatility.for casting films. In the case of PNNA with N - 950 x 10, CO was dissolved in hot chlorobenzene and tnen mixed with PNNA (also in chlorobenzene). Solvent choice was a matter of convenience. 

Acridine and diphenyl butadiene were obtained from Aldrich poly (methylmethacrylate)(PMMA) from KTI Chemicals (as a 9 wt.% solution in chlorobenzene). Solutions for spin-casting were prepared as follows 1 ml of IM acridine (in 2-ethoxy ethyl acetate) in 9 ml of 9 wt.% PMMA (thus 16 wt.% acridine in film) 0.3 g diphenyl butadiene in 7 ml of 9% PMMA solution (thus 30 wt.% diphenyl butadiene)... 

Recently, uniform fdms with high concentrations of Cgo were cast from 1,2-di-chlorobenzene solutions containing up to 1 4 weight ratio MEH-PPV Cgo [110]. For devices made from these high concentration blends, charge collection efficiencies around 7 =26% (electron/incident photon) and power conversion efficiencies around 7e = 2.5% (electrical power out/incident light power) have been realized. 

Chlorination of benzene may lead to the formation of various chlorinated products. Commercial chlorination is generally carried out in tall cast-iron or steel tanks which have been lined with pure lead, then tile (55). The process is regulated so that chlorobenzene is the chief product. Wiegandt and Lantos (77) developed a process for improved yields of p-dichlorobenzene. Hexachlorocyclohexane is generally obtained by photochemical chlorination of benzene 40, 55). 

Two qualitative conclusions may be drawn from these fluorescence results. The first point is related to whether there is residual casting solvent that might affect the morphology of the film. It is not possible to comment on the presence of residual chlorobenzene or toluene from the results of this study because of the lack of any dramatic change in R or excimer band position upon annealing. No separate gravimetric studies of solvent evaporation were conducted in this work, although such experiments have been... 

Fig. 22 Optical transmission spectra of 100-nm-thick MDMO-PPV PCBM (1 4 by wt.) films spin cast onto glass substrates from either toluene (dashed line) or chlorobenzene (solid line) solutions (a). Incident photon to collected electron (IPCE) spectra (b) and current-voltage characteristics (c) for photovoltaic devices using these films as the active layer. (Reprinted with permission from [34], 2001, American Institute of Physics)...

Hoppe et al. studied MDMO-PPV PCBM solar cells for decoding the different nanophases within these MDMO-PPV PCBM blends cast from the two solvents (toluene and chlorobenzene) [55]. A large difference in the scale of phase separation could be identified as a major difference between toluene and chlorobenzene cast blends (see Fig. 23), but this could not directly explain the observed differences in photocurrent generation [55]. 

Fig. 23 Tapping mode AFM topography scans of MDMO-PPV PCBM 1 4 blended films, spin cast from a chlorobenzene and b toluene solution. Clearly a larger scale of phase separation is observed for the toluene cast film. (Reproduced from [55] with permission, 2004, Wiley-VCH)...

The commonly observed larger scale of phase separation of the toluene cast MDMO-PPV PCBM blends has generally been interpreted as the main reason for the reduced photocurrents in comparison to those of the chlorobenzene cast blends. It can then be expected that a lower charge carrier generation efficiency may result when exciton diffusion lengths of 10-20 nm are well exceeded by the PCBM cluster size (200-500 nm), since many exci-tons are generated within these clusters. Experimentally, it has been identified that indeed some unquenched photoexcitations give rise to residual PCBM photoluminescence in toluene cast blends, whereas in chlorobenzene cast... 

Deeper insight can be gained from a scanning near-field optical microscopy (SNOM) study by McNeill et al., who resolved the local photocurrent obtained on MDMO-PPV PCBM toluene cast blends [138]. The authors revealed that the photocurrent was considerably reduced on top of the small hUls caused by the PCBM clusters (Fig. 25), whereas it stayed nearly constant over the surface of chlorobenzene cast blends [ 138]. 

Fig. 36 XRD crystallinity (a) and absorption coefficient (b) of P3HT PCBM blends spin cast from either chlorobenzene (left) or chloroform (right) at various annealing temperatures. Interestingly, the increase in crystallinity is accompanied by a quantitatively correlated increase in optical absorption in the 2.0-2.5 eV region. (Reprinted from [183], 2006, with permission from Elsevier)...

Films of pure PMPS were cast from a 1% solution of the polymer in chloroform on the surface of sodium chloride plates. The solvent was allowed to evaporate at room temperature and the films finally dried for 1 hr at 110 C. Alternatively, films were spin coated from chlorobenzene solution onto silicon substrates which were undoped and polished on both sides. As such they are transparent in the IR down to 600 700 cm-1. 

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