Cyclohexane production figures

Figure 5.2-44. Cyclohexane production-UOP process (after Chauvel et al. [63]).

The Amano researchers found not just drastically different enantiomeric excesses in the Pseudomonas sp. (Amano AH) lipase-catalyzed hydrolysis of methylene-oxypropionyl or -pivaloyl diesters, but a near-total reversal of specificity. Whereas in cyclohexane the different esters yielded half-esters with 88.8-91.4% e.e. -specificity for a triple mutant ( FVL ) of Amano PS lipase, the same transformation with the same enzyme in diisopropyl ether (DIPE) yielded between 68.1 and > 99% e.e. of the S-product (Figure 12.10) (Hirose, 1992,1995). 

In addition several other materials have been reported by industrial companies, but have not at the time of writing been commercialised. These include the product of condensation of 2,2-bis-(p-aminocyclohexyl)propane (VI) (Figure 18.28) with a mixture of adipic and azelaic acid (Phillips Petroleum), a research material produced in the old German Democratic Republic obtained by melt condensation of /ranj -cyclohexane-l,4-dicarboxylic acid (VII) (Figure 18.28) and the two trimethylhexamethylenediamine isomers used in the manufacture of Trogamid T, and another amorphous material (Rilsan N by Ato Chimie). 

Older methods use a liquid phase process (Figure 10-11). ° New gas-phase processes operate at higher temperatures with noble metal catalysts. Using high temperatures accelerates the reaction (faster rate). The hydrogenation of benzene to cyclohexane is characterized by a highly exothermic reaction and a significant decrease in the product volume... 

No hypotheses can be advanced for the sequences involved in the oxidation of cyclohexanepentols which react even more slowly with periodate than does (+)-quercitol. For instance, when the all-trans l 3, 5/2, 4-cyclohexanepentol (33) is oxidized (Figure 6), production of malonaldehyde starts very early and the time curve of periodate reduction indicates a very complex reaction. Nor is it possible to analyze satisfactorily the curves obtained with (1 l)-1, 2, 4/3, 5-cyclohexane-pentol (34) or with dl-1, 2, 3, 4/5-cyclohexanepentol (35) [this is the configuration predicted for the (1 D)-entantiomorph (41)]. 

Another reaction which enjoys much commercial interest is the production of adipic acid from cyclohexane oxidation. The two types of processes that are employed commercially are outlined in Figure 24. 

The influence of the lipophilic external phase on the production of xylan-based microparticles by interfacial cross-linking polymerization has been investigated (Nagashima et al., 2008). Three different external phases were investigated a 1 4 (v/v) chloroform cyclohexane mixture, soybean oil, and a medium chain triglyceride, with viscosities below 1, 24, and 52 cP, respectively. It was observed that the use of these different lipid phases results in different macroscopic and microscopic aspects of the system (Figure 10). 

Figure 3. Radioactivity in products. n-Hexane- C/ Cyclohexane/H2 over Te-NaX at 450 C.

Figure 7.7 STM images of Pt(lll) at 300K (a) (75 x 75) A2, 20 mTorr cyclohexene plus 20mTorr H2 no catalytic products formed (b) (50x 50)A2, 200 mTorr H2, 20 mTorr of cyclohexene, disordered surface and cyclohexane formed (c) (90 x 90) A2, CO added, no catalytic activity. (Reproduced from Ref. 11).

The spray paint can was inverted and a small amount of product was dispensed into a 20 mL glass headspace vial. The vial was immediately sealed and was incubated at 80°C for approximately 30 min. After this isothermal hold, a 0.5-mL portion of the headspace was injected into the GC/MS system. The GC-MS total ion chromatogram of the paint solvent mixture headspace is shown in Figure 15. Numerous solvent peaks were detected and identified via mass spectral library searching. The retention times, approximate percentages, and tentative identifications are shown in Table 8 for the solvent peaks. These peak identifications are considered tentative, as they are based solely on the library search. The mass spectral library search is often unable to differentiate with a high degree of confidence between positional isomers of branched aliphatic hydrocarbons or cycloaliphatic hydrocarbons. Therefore, the peak identifications in Table 8 may not be correct in all cases as to the exact isomer present (e.g., 1,2,3-cyclohexane versus 1,2,4-cyclohexane). However, the class of compound (cyclic versus branched versus linear aliphatic) and the total number of carbon atoms in the molecule should be correct for the majority of peaks. 

Co-condensation of tungsten atoms with a mixture of cyclohexane and PMe3 gives a mixture a products shown in Figure 6 12 6). The identity of the... 

Incorporation of the carboxylic acid group into the substrate also had an effect on the stereochemistry of the Alder-ene products. Trost and Gelling60 observed diastereoselectivity in the palladium-catalyzed cycloisomerization of 1,7-enynes when the reactions were conducted in the presence of A,A-bis(benzylidene)ethylene diamine (BBEDA, Figure 2). They were able to synthesize substituted cyclohexanes possessing vicinal (Equation (53)) and... 

The prototype reaction was the hydroformylation of oleyl alcohol (water insoluble) with a water-soluble rhodium complex, HRh(C0)[P(m-C6H4S03Na)3]3 (Figure 6.5). Oleyl alcohol was converted to the aldehyde (yield = 97%) using 2 mol % Rh with respect to the substrate and cyclohexane as the solvent, at 50 atmospheres CO/H2, and 100°C. The SAPCs were shown to be stable upon recycling, and extensive work proved that Rh is not leached into the organic phase. Since neither oleyl alcohol nor its products are water soluble, the reaction must take place at the aqueous-organic interface where Rh must be immobilized. Also, if the metal catalyst was supported on various controlled pore glasses with... 

Adipic acid is produced by oxidizing cyclohexane. The two-step process shown in Figure 18—1 is used for almost ail production. Cyclohexane is oxidized with air over a cobalt naphthenate catalyst to give a mixture of... 

The reaction of AsPhs with Ni/AhOs in n-heptane solution, under hydrogen (12 bar) at between 25 and 200 °C, only takes place on the nickel surface and is characterized by benzene (and cyclohexane, secondary product) evolution [135]. At 80 °C, saturation of the nickel surface has been reached with a ratio As/Nis of 1. At 100 °C, arsenic migration from the nickel surface to the core of the particle is observed. This migration is characterized by a rapid decrease in ferromagnetism of the nickel particles, reaching zero for an As/Ni ofO.45. At 170 °C, NiAs alloy formation has been highlighted by its X rays diffraction pattern (Figure 2.18). 

Figure 11.2 shows a cyclohexane oxidation reactor. The further oxidation of the ketone and alcohol to adipic acid is very complex but occurs in good yield, 94%, despite some succinic and glutaric acid by-products being formed because the adipic acid can be preferentially crystallized and centrifuged. 

For a given surfactant, the ability to form a single-phase w/o microemulsion is a function of the type of oil, nature of the electrolyte, solution composition, and temperature (54-58). When microemulsions are used as reaction media, the added reactants and the reaction products can also influence the phase stability. Figure 2.2.4 illustrates the effects of temperature and ammonia concentration on the phase behavior of the NP-5/cyclohexane/water system (27). In the absence of ammonia, the central region bounded by the two curves represents the single-phase microemulsion region. Above the upper curve (the solubilization limit), a water-in-oil microemulsion coexists with an aqueous phase, while below the lower curve (the solubility limit), an oil-in-water water microemulsion coexists with an oil phase. It can be seen that introducing ammonia into the system results in a shift of the solubilization... 

The key intermediates in the process are the silylenes and the radical fragments, both of which should be amenable to trapping experiments. With this in mind, two representative, polysilane derivatives 6 and 9, were irradiated (254 nm) in the presence of excess triethylsilane, and the results of this experiment are shown in Figure 6. Since the polysilane 9 was not soluble in the trapping reagent, it was dissolved in cyclohexane which contained a 100 fold molar excess of triethylsilane. In each case, the major isolable volatile products... 

The fact that the catalyst can promote dehydrogenation as well as isomerization is shown in Figure 5, where the weight per cent benzene in the products of experiments on dehydrogenation of cyclohexane is shown plotted against the reaction temperature. These results are compared to Von Muffling s (7) calculated equilibrium line. The... 

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