Alkylnaphthalenes

Pour-Point Depressants. The pour point of alow viscosity paraffinic oil may be lowered by as much as 30—40°C by adding 1.0% or less of polymethacrylates, polymers formed by Eriedel-Crafts condensation of wax with alkylnaphthalene or phenols, or styrene esters (22). As wax crystallizes out of solution from the Hquid oil as it cools below its normal pour point, the additive molecules appear to adsorb on crystal faces so as to prevent growth of an interlocking wax network which would otherwise immobilize the oil. Pour-point depressants become less effective with nonparaffinic and higher viscosity petroleum oils where high viscosity plays a dominant role in immobilizing the oil in a pour-point test. 

This article deals mainly with naphthalene [91-20-3]. The hydrogenated naphthalenes, the alkylnaphthalenes (particularly methyl- and isopropylnaphthalenes), and acenaphthene also are discussed (see also Naphthalenederivatives). 

Isopropylnaphthalenes produced by alkylation of naphthalene with propjdene have gained commercial importance as chemical intermediates, eg, 2-isopropylnaphthalene [2027-17-OJ, and as multipurpose solvents, eg, mixed isopropylnaphthalenes. Alkylation of naphthalene with alkyl haUdes (except methyl hahdes), acid chlorides, and acid anhydrides proceeds in the presence of anhydrous aluminum chloride by Friedel-Crafts reactions (qv). The products are alkylnaphthalenes or alkyl naphthyl ketones, respectively (see Alkylation). 

All lnaphthalenesulfonic Acids. The aLkyLnaphthalenesulfonic acids can be made by sulfonation of aLkyLnaphthalenes, eg, with sulfuric acid at 160°C, or by alkylation of naphthalenesulfonic acids with alcohols or olefins. These products, as the acids or their sodium salts, are commercially important as textile auxiUaries, surfactants (qv), wetting agents, dispersants (qv), and emulsifying aids, eg, for dyes (qv), wettable powder pesticides, tars, clays (qv), and hydrotropes. 

In 1994 estimated naphthalene consumption in western Europe and Japan for the production of alkylnaphthalene sulfonates, naphthalene sulfonate formaldehyde condensates, and synthetic tanning agents was... 

Nevertheless, a number of gas chromatographic applications exist, epecially those for the determination of crude oil indicators. Such indicators are used as geochemical parameters for the thermal history of the crude as well as to indicate the possible relationship between crudes from different wells. These indicators comprise a number of isomeric aromatic species, such as the individual alkylnaphthalenes (44, 45), the individual Cio-mono-aromatics or the individual C9-mono-aromatics. The ratio between these isomers gives a definite indication of the crude oil. In general, these systems use a Deans switching unit to make a heart-cut, which then is focused, reinjected and separated on a second column with a different polarity. 

R. G. Schaefer and J. Holtkemeier, Direct analysis of alkylnaphthalenes in cmde oils by two-dimensional capillary gas cliromatography , Chromatographia 26 311-315 (1988). 

Characteristic fragment ions of alkylnaphthalenes are m/z 141 and 115. Using the GC conditions mentioned previously, most of the... 

The potential of MIL-47 and MIL-53(A1) for adsorption of other types of aromatic adsorbates has also been explored, for instance, of dichlorobenzene, cresol, or alkylnaphthalene isomers [17, 98]. The removal of sulfur-containing aromatics from fuels via physisorption on MOFs has been investigated on several instances in literature, for instance, via the selective removal of thiophene from a stream of methane gas by MIL-47 [99], the removal of tetrahydrothiophene from methane by... 

Determination of degradation by measurement of loss may be ambiguous since this fails to take into account transformation to metabolites. At field sites, loss by other processes such as volatilization is difficult to assess, but may be inferred, for example, from low concentrations of the more volatile alkylnaphthalenes. The use of stable isotopes is discussed in Chapter 13. 

Phousongphouang, P.T., Arey J. (2002) Rate constants for the gas-phase reactions of a series of alkylnaphthalenes with the OH radicals. Environ. Sci. Technol. 36, 1947-1952. 

AT-Alkyl methanesulfonamides, 23 685 Alkyl monoperoxycarbonic acid, 18 466 Alkylnaphthalenes, 17 84-85 dispersant moieties, 8 706t Alkyl naphthalene sulfonates, 24 146 Alkylnickel, re-complexes of, 17 116 Alkyl nitrites, formation of, 17 165-166 Alkylonium salt hydrates, 14 171... 

Differences in polynuclear aromatic hydrocarbons (PAHs) are shown as bar diagrams in Figure 4.17a and b. The high abundance of alkylbenzenes and alkylnaphthalenes... 

Choose alkylnaphthalene sulfonates and sulfosuccinate esters as hydrotropes in formulations where foaming needs to be controlled, as they enhance solubility of anionic surfactants without increasing foam amount [20],... 

The alkyl-substituent pattern for some PAHs series (e.g., alkylnaphthalenes, phenanthrene/anthracene, pyrene/fluoranthene, m/z 228 and m/z 252) are shown in Figs. 6-9, respectively. The parent PAHs and their alkylated homologs are determined in GC-MS data by monitoring their corresponding molecular weights. For example, for the naphthalene series the ions at m/z 128,142 methyl-naphthalenes, 156 C2-naphthalenes, 170 C3-naphthalenes, and 184 C4-naphtha-lenes are monitored (Fig. 6). The GC elution orders of the C2-naphthalene and C3-naphthalene isomers have been reported [144,145]. 

There are indications that pure naphthalene (a constituent of mothballs, which are, by definition, toxic to moths) and alkylnaphthalenes are from three to 10 times more toxic to test animals than are benzene and alkylbenzenes. In addition, and because of the low water solubility of tricyclic and polycyclic (polynuclear) aromatic hydrocarbons (i.e., those aromatic hydrocarbons heavier than naphthalene), these compounds are generally present at very low concentrations in the water-soluble fraction of oil. Therefore, the results of this smdy and others conclude that the soluble aromatics of crude oil (such as benzene, toluene, ethylbenzene, xylenes, and naphthalenes) produce the majority of its toxic effects in the enviromnent. 

Shape Selective Reactions of Alkylnaphthalenes in Zeolite Catalysts... 

A cracking process, the dealkylation of alkylbenzenes, became an established industrial synthesis for aromatics production. Alkylbenzenes (toluene, xylenes, tri-methylbenzenes) and alkylnaphthalenes are converted to benzene and naphthalene, respectively, in this way. The hydrodealkylation of toluene to benzene is the most important reaction, but it is the most expensive of all benzene manufacturing processes. This is due to the use of expensive hydrogen rendering hydrodealkylation too highly dependent on economic conditions. 

Studies of Lewis acid-catalyzed isomerization of alkylnaphthalenes were carried out by Olah and Olah in connection with alkylation of naphthalene with alkyl halides.88 Methyl-, ethyl-, isopropyl- and ferf-butylnaphthalene readily undergo isomerization with A1C13 in CS2 solution. The rate of isomerization and the equilibrium concentration of the p isomer were found to increase with increasing branching of the alkyl substituent (Table 4.3). 

Alkylation with isobutylene under similar conditions167 and alkylation with propylene catalyzed by perfluorosulfonic acids,168 in turn, lead to 2-substituted naphthalenes. As was shown by Olah and Olah,169 the kinetic alkylation of naphthalene, even in case of rm-butylation, gives preferentially the 1-isomers, which, however, isomerize very fast to the thermodynamically preferred 2-alkylnaphthalenes. Great care is therefore needed to evaluate kinetic regioselectivities. 

Alkylnaphthalenes are more reactive than alkylbenzenes and react at temperatures as low as 90°C. Sodium is a selective catalyst for side-chain monoalkylation. More elevated temperatures and prolonged reaction times allow the replacement in ethylation of all a-hydrogen atoms of alkylnaphthalenes with high selectivity.238... 

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