Decalins aromatization

The following solvents generally contain peroxides light petroleum, petrol (U.S. gas), decalin, aromatic hydrocarbons containing side chains (xylene, cumene), tetralin, all ethers. 

It is a typically aromatic compound and gives addition and substitution reactions more readily than benzene. Can be reduced to a series of compounds containing 2-10 additional hydrogen atoms (e.g. tetralin, decalin), which are liquids of value as solvents. Exhaustive chlorination gives rise to wax-like compounds. It gives rise to two series of monosubstitution products depending upon... 

CoF is used for the replacement of hydrogen with fluorine in halocarbons (5) for fluorination of xylylalkanes, used in vapor-phase soldering fluxes (6) formation of dibutyl decalins (7) fluorination of alkynes (8) synthesis of unsaturated or partially fluorinated compounds (9—11) and conversion of aromatic compounds to perfluorocycHc compounds (see Fluorine compounds, organic). CoF rarely causes polymerization of hydrocarbons. CoF is also used for the conversion of metal oxides to higher valency metal fluorides, eg, in the assay of uranium ore (12). It is also used in the manufacture of nitrogen fluoride, NF, from ammonia (13). 

At room temperature, HDPE is not soluble in any known solvent, but at a temperature above 80—100°C, most HDPE resins dissolve in some aromatic, aflphatic, and halogenated hydrocarbons. The solvents most frequently used for HDPE dissolution are xylenes, tetralin, decalin 1,2,4-trimethylbenzene, o-dichlorobenzene, and 1,2,4-ttichlorobenzene. 

Chemical Properties and Reactivity. LLDPE is a saturated branched hydrocarbon. The most reactive parts of LLDPE molecules are the tertiary CH bonds in branches and the double bonds at chain ends. Although LLDPE is nonreactive with both inorganic and organic acids, it can form sulfo-compounds in concentrated solutions of H2SO4 (>70%) at elevated temperatures and can also be nitrated with concentrated HNO. LLDPE is also stable in alkaline and salt solutions. At room temperature, LLDPE resins are not soluble in any known solvent (except for those fractions with the highest branching contents) at temperatures above 80—100°C, however, the resins can be dissolved in various aromatic, aUphatic, and halogenated hydrocarbons such as xylenes, tetralin, decalin, and chlorobenzenes. 

Above 100°C, most polyolefins dissolve in various aHphatic and aromatic hydrocarbons and their halogenated derivatives. For example, polybutene dissolves in benzene, toluene, decalin, tetralin, chloroform, and chlorobenzenes. As with other polyolefins, solubiHty of PB depends on temperature, molecular weight, and crystallinity. 

Chemical Designations - Synonyms Bicyclo [4.4.0] Decane Naphthalane Perhydronaphthlene Dec Decalin De Kalin Naphthane sic- or trans-Decahydronaphthalene Chemical Formula CjoHu. Observable Characteristics - Physical State (as normally shipped) Liquid Color Colorless Odor Aromatic, like turpentine mild, characteristic. 

In alicyclic hydrocarbon solvents with aromatic solutes, energy transfer (vide infra) is unimportant and probably all excited solute states are formed on neutralization of solute cations with solute anions, which are formed in the first place by charge migration and scavenging in competition with electron solvent-cation recombination. The yields of naphthalene singlet and triplet excited states at 10 mM concentration solution are comparable and increase in the order cyclopentane, cyclohexane, cyclooctane, and decalin as solvents. Further, the yields of these... 

Naphthalene itself is solid at ambient temperatures (m.p. 80.5°C) but is dissolved easily in aromatic compounds such as toluene (refer Table 13.1) [10,12], so that the oily mixture can be handled as a "naphthalene oil." The naphthalene oil is catalytically hydrogenated to decalin and methylcyclohexane simultaneously. Decalin and methylcyclohexane are converted into hydrogen and naphthalene oil again by dehydrogenation catalysis. From the handling viewpoint, the naphthalene oil may be deemed as a preferential and practical material for hydrogen storage and transportation. 

Dehydrogenation activities, compared for tetralin and decalin [5,12] under the same superheated liquid-film conditions over the same Pt/C catalyst, exhibited around 3.9-63 times preference of tetralin (Table 13.3), which can certainly be ascribed to advantageous adsorption due to the a-bonding capability of its aromatic part [17-19]. It was, thus, confirmed experimentally that tetralin is superior to decalin as the organic hydrogen carrier for stationary applications in terms of rapid hydrogen supply or power density, provided that the density of fuel storage is unimportant. 

Because the cis-decalin molecule extends its two methine carbon-hydrogen bonds on the same side in contrast to frans-decalin, the carbon-hydrogen bond dissociation of adsorbed decalin would be advantageous to the cis-isomer on the catalyst surface (Figure 13.17). A possible reaction path by octalin to naphthalene in dehydrogeno-aromatization of decalin will be favored to the cis-isomer, since its alkyl intermediate provides the second hydrogen atom from the methine group to the surface active site easily. 

Takaiwa, S., S. Hodoshima, H. Arai, and Y. Saito, Liquid-phase dehydrogeno-aromatization catalysis of decalin for pure hydrogen/air fuel cell. /. Hydrogen Energy Syst. Soc. Jpn., 26(2), 44-49 (2001). 

Unlike the ring opening of decalin, the RO of naphthenic compounds containing at least one benzene ring (i.e. tetralin, naphthalene, etc.) are much slower due to the presence of aromatic rings. Corma et al.A1 has reported differences in activity... 

HP-6 Reference to aromatic systems stability, orientation rules and their relationship with more or less unsaturated cyclohexane rings and decalin systems. 

Bhattacharyya et al. reported the first total synthesis of clausenalene (90) to establish its structure (99). This total synthesis uses Japp-Klingemann and Fischer-Borsche reactions as key steps. The phenyl hydrazone 1000 required for the transformation to 1-0x0-tetrahydrocarbazole 1001 under Fischer-Borsche conditions was obtained by condensation of 2-hydroxymethylene-5-methylcyclohexanone (999) with diazotized 3,4-methylenedioxyaniline (998) using Japp-Klingemann conditions. Wolff-Kishner reduction of 1001 furnished 3-methyl-6,7-methylenedioxy-l,2,3,4-tetrahydrocarbazole (1002), which, on aromatization wifh 10% Pd/C in decalin, afforded clausenalene (90) (99) (Scheme 5.143). 

Though safer than the decomposition of pure, solid diazonium tetrafluoroborates, dediazoni-ation of these compounds mixed with inert solid salts cannot be scaled up to a large extent since heat exchange through large quantities of powdered solids rapidly becomes difficult. Thus, dediazoniation of arenediazonium tetrafluoroborates suspended in inert fluids is an alternative proposition.13105 141 175-219 220 In addition to the safety improvement, lower quantities of tar are formed using this technique. The inert fluid can be ligroin,143 petroleum ether,147 Decalin,3 or simple aromatic compounds,1-3,5,131-221 such as toluene, xylene, biphenyl, nitrobenzene,177 or quinoline. Simple esters have also been used as solvents in the dediazoniation... 

Table 2.2, which shows results for some polyolefines, indicates for these polymers a similar insensitivity of the stress-optical coefficinet to molecular weight and concentration as Table 2.1 for polystyrene. A typical solvent effect is noticed for all the three types of polyolefins, viz. that the stress-optical coefficient in decalin is considerably smaller than that in aromatic solvents. This effect was discovered by Garmonova (71). 

Reduction of arenes.1 Raney nickel (Mozingo type) in combination with 2-propanol (reflux) effects reduction of aromatic rings in 2-18 hours. Naphthalene is reduced in 18 hours to tetralin (90% yield) and cis- and frans-decalin (10% yield). Anisole is reduced in 110 hours to cyclohexyl methyl ether (90% yield). Nitrobenzene is reduced quickly to aniline and then further to cyclohexylamine and cyclohexylisopropylamine. 

Tetralin. The presence of an aromatic ring in the molecule induces important changes with respect to the saturated homologue (decalin). Firstly, the photochemical oxidation (i.e. in the absence of titania) is very important (see Fig. 1) as expected from the absorption spectrum it produces principally 2-tetralone as the main product and 1 -tetralone. Secondly, the photocatalytic oxidation occurs principally at position 1 (see. Fig. 1 and the following scheme). Note that this scheme refers to both photocatalytic and photochemical products however, because of the role of inner filter played by Ti02, the former products should be predominant. 

---