1.4- Dimethyl-naphthalene

Under the same conditions the even more reactive compounds 1,6-dimethylnaphthalene, phenol, and wt-cresol were nitrated very rapidly by an autocatalytic process [nitrous acid being generated in the way already discussed ( 4.3.3)]. However, by adding urea to the solutions the autocatalytic reaction could be suppressed, and 1,6-dimethyl-naphthalene and phenol were found to be nitrated about 700 times faster than benzene. Again, the barrier of the encounter rate of reaction with nitronium ions was broken, and the occurrence of nitration by the special mechanism, via nitrosation, demonstrated. 

Similar regiospecific syntheses employing PMBs and diaLkylnaphthalene have been used to prepare 2,6-dimethyl naphthalene [581-42-0] which is oxidized to the corresponding 2,6-naphthalenedicarboxyHc acid [1141-38-4] also used as a monomer for Hquid crystal polymers. 

The most recent researches of Capellos and Suryanarayana on the triplet excited states of 1,2- and 1,8-dinitronaphthalenes, and those of Capellos and Lang on the triplet excited states of 4-nitronaphthalene and 4-nitro-N, N -dimethyl-naphthalene have been accepted for publication by the International Journal of Chemical Kinetics Refs 1) G. Schultz K.L. Ganguly, Ber 56,... 

The UV spectrum of the chiral molecule 46 a differs from 2,6-dimethyl-naphthalene by a long-wave shift of the first absorption band and almost complete disappearance of the sharp vibration structure of the naphthalene spectrum. 

These conclusions were not applicable when sediment was the source of hydrocarbons. McCain et al. (5) studied the bioavailability of petroleum in sediment to English sole (Parophrys vetu-lus). Sediments rich in alkylated and non-alkylated benzenes and naphthalenes, together with fluorene and phenanthrene, were employed. After 11 days of exposure, samples of skin, muscle, and liver were examined. Fluorene and phenanthrene were not accumulated in the test fish however, significant concentrations of 1-methyl naphthalene, 2-methyl naphthalene, 2,6-dimethyl naphthalene and 1,2,3,4-tetramethylbenzene, were found in skin and liver (Table II) 1-methyl naphthalene and 2-methyl naphthalene were the major components of muscle. In each tissue examined, 1-methyl-naphthalene was the major component 1,2,3,4-tetramethylbenzene occurred in relatively low concentrations in skin and muscle in comparison to naphthalenes containing one and two alkyl groups. 

Kraikul, N., Rangsunvigit, P., and Kulprathipanja, S. (2005) Study on the adsorption of 1,5-1, 5- and 2,5-dimethyl-naphthalene on a series of alkaline and alkaline earth ion-exchanged faujasite zeolites. Adsorption, 12, 317. 

In additional experiments, HZSM-5 was precoked by converting methanol alone (into hydrocarbons) at 400 °C. Afterwards the zeolite was exposed to the 2-methylnaphtha-lene/methanol mixture, under the usual reaction conditions. The initial yield of 1-methylnaphthalene was significantly reduced (1.5 % compared to 4 % for the fresh catalyst, cf. Fig. 4). Furthermore, the initial content of 2,6- + 2,7-dimethylnaphthalene in the dimethyl-naphthalene fraction was 84 % instead of 70 % for the fresh catalyst. In another run, HZSM-5 was loaded with 0.5 wt.-% of Pt, and H2 was used as carrier gas instead of N2. Under these conditions, the formation of coke was avoided or at least drastically diminished. In-line with our model, no changes in the product yields and in the distribution of the dimethylnaphthalene isomers were observed with time on stream. 

M = Solvent Pyrene Paraffin oil 1-Methyl-naphthalene Ethanol 2-Methyl- naphthalene Ethanol 1,6-Dimethyl-naphthalene Ethanol 1-Methoxy- naphthalene Toluene 2-Methoxy- naphthalene Toluene... 

Copolynaphthalene ester films were prepared by transesterification/esterifi-cation of dimethyl naphthalene dicarboxylate and dimethyl isophthalate with aliphatic diols by Hebrink et al. (1) and used in optical polarizing films with color shifts. 

Voluminous studies have been made to distinguish the reactivity of singlet oxygen, triplet oxygen, and electron transfer-generated superoxide (228). For example, while superoxide gives both endoperoxide and side chain oxidation of 1,4-dimethyl-naphthalene, eq. 73 (229),... 

The reaction of nitronaphthalenes and nitroisoquinolines with dimethyl phosphite in MeONa/MeOH (equation 27), proceeded via nucleophilic substitution of hydrogen according to a redox stoichiometry and gave substituted dimethyl naphthalene- and isoquinoline-phosphonates and benzazepines.214... 

Experiments suggested a potential cesium-stripping problem in the CSSX process due to the presence of nitrite in the waste stimulant. The true reason for the cesium-stripping problem was, in fact, the presence of surfactant (sodium mono- and dimethyl naphthalene sulfonate) that can partition into the organic phase on extraction and then retain cesium upon stripping. To overcome this drawback, the authors proposed a caustic wash with a moderate concentration of sodium hydroxide sufficient to remove enough of these lipophilic anions to rejuvenate the solvent, therefore,... 

At concentrations normally encountered in environmental situations, sorption often has been observed to be relatively non-competitive. For example, Chiou et al. (1983, 1985) found no competition in the sorption of binary solutes m-dichlorobenzene and 1,2,4-trichlorobenzene and between parathion and lindane. MacIntyre and deFur (1985) measured the sorption of methyl and dimethyl naphthalene, individually and as components of JP-8 and synthetic jet fuel mixtures on two sediments and montomorillonite clay in water. The sorption coefficients of the naphthalenes generally varied by less than a factor of two. 

The main impurity in crude 78°C coal-tar naphthalene is sulfur that is present in the form of thionaphthene (1 to 3%). Methyl- and dimethyl-naphthalenes also are present (1 to 2%) with lesser amounts of indene, methylindenes, tar acids, and tar bases. 

Figure 1. Solubility of 2,3 dimethyl naphthalene (DMN) in supercritical carbon dioxide using the Redlich-Kwong...

Treatment Is 210°C, 4 hours. While more than sixty compounds were observed, only ten were identified by GC-MS using computer library searches as shown in Table I. The identified compounds include ionene, 2,6-dimethylnaphthalene, ethyltoluene, tetrahydro-dimethyl-naphthalene, butadienyl-trimethylcyclohexenone, dihydroactinidi-olide, 13-cyclocitral, trimethyl-cyclohexenyl-propenal, retinol and tetrahydro-trimethylbenzofuranone. 

We have described elsewhere the nature of the MI FTIR spectra of PAHs and their derivatives (1, 12, 13, 1J>, 18, 21-24) the following points are especially significant. First, FTIR spectra devoid of rotational structure and having individual bandwidths on the order of 2-7 cm are obtained both for PAHs and for polar derivatives thereof (such as nitrogen heterocycles) These spectra are sufficiently characteristic to enable identification of individual isomers to be made in mixtures [e.g., the six methylchrysenes (12) and the various mono- and dimethyl naphthalenes and biphenyls (24)]. Second, detection limits for individual PAHs can be as low as 50 ng, if special "micro samp ling 1 deposition apparatus is used (23) Third, Beer s law plots typically are linear over 1.5-2 decades in PAH concentration by the complementary use of two different deposition cells, linearity over 3 decades in PAH concentration for Beer s law plots can be approached (23). Finally, for both MI FTIR and MI fluorescence spectrometry, analytical precision of ca. 3-7 % relative standard deviation can be achieved. 

Recently there have been several observations of exciplex formation in the gas phase. Exciplexes between 9,10-dicyanoanthracene and 1,5-dimethyl-naphthalene (Itoh et ai, 1981) and 1,2-dimethoxybenzene, hexamethyl-benzene and 2,5-dimethylhexa-2,4-diene (Hirayama and Phillips, 1981) have been studied. The work of Hirayama and Phillips showed that the wavelength of exciplex emission in the gas phase is very similar to that obtained in cyclohexane solution. Measurement of wavelengths of exciplex emission in the gas phase enable one to probe solvent polarity properties using eqn (20) more accurately since Vq is now known. Here is the frequency of emission... 

SODIUM METHYLATE pN 1431) pop see SIK450 SODIUM (2-METHYL-4-CHLOROPHENOXpACETATE see SIL500 SODIUM MOLYBDATE see DXE800 SODIUM MOLYBDATE( T) see DXE800 SODIUM MONOCHLORACETATE see SFU500 SODIUM MONO- and DIMETHYL NAPHTHALENE SULFONATE see SIM400... 

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