Naphthalene product ratio

Some data on the alkylation of naphthalene by 2-bromopropane using A1C13 under different conditions are given below. What factors are responsible for the differing product ratios for the two solvents, and why does the product ratio change with time ... 

The type of treatment applied significantly affected the benzene/naphthalene (B/N) product ratio (Fig. 6). Thus, treatment with oxalic and citric acids, steaming plus HC1 washing, and partial Cs-exchanged increased the B/N ratio with respect to the untreated sample. In the first three cases, this effect may be explained by a preferential removal of the acid sites at the external zeolite surface, where naphthalene is predominantly formed [6], The reason of the increased B/N ratio in the 3Mo/CsHZ5 sample still needs to be elucidated, but a decrease in surface acidity in combination with an enhanced shape selectivity effect due to presence of voluminous Cs+ cations inside the micropores (a decrease in Vmicrop was noticed in Table 1) may be hypothesized. 

Stuerga et al. [74] showed that, in the sulfonation of naphthalene, the ratio of the products, naphthalene-1- and 2-sulfonic acids, depends on the MW power applied. Higher powers, which cause higher heating rates, increase the proportion of the thermodynamically more stable product, naphthalene 2-sulfonic acid, in the product mixture. 

As is evident from the Table 2, zeolite H-beta is found to be the most active and selective catalyst in the conversion of benzylchloride and formation of 2-BN. The conversion of benzylchloride over H-beta, H-Y and AICI3 are found to be 32 2, 22.08 and 28.3 wt.% respectively. The corresponding product ratio of 2-BN/l-BN are 0.36, 0.28 and 0.28 respectively. These results show that the Lewis acid catalyst, AICI3 and H-Y do not possess shape-selectivity and naphthalene is attacked preferentially to yield higher amount of 1-BN because 1-position of naphthalene is more reactive than 2-position. Presumably, the higher activity of H-beta may be attributed to its stronger acid sites and stacking faults in the... 

Determining the thermal maturity of light oils and condensates can be difficult. Biomarker concentrations in crude oils are low and biomarker maturity parameters have limited applicability at high levels of thermal maturity (Peters and Moldowan, 1993). Light hydrocarbons (C6-C7) are volatile, susceptible to biodegradation and maturity parameters derived from these compounds may be unreliable. In this chapter, we report on the correlation of C4-benzene and C4-naphthalene compounds with thermal maturity in oil cracking pyrolysis products of a Western Canada Sedimentary Basin (WCSB) oil. The use of C4-benzene and C4-naphthalene compound ratios as thermal maturity indicators in natural systems was evaluated using crude oils from the Fort Worth Basin, Texas, USA. 

Moderate stereoselectivity is also seen in the addition of phenoxycarbene to cyclohexene, in which the product ratio is apparently influenced by steric factors that favor introduction of the larger group (PhO versus H) in the less crowded exoposition (Scheme 5.31). 1,6-Methanocyclodecapentaene is formally derived from naphthalene by addition of CH2 to the 1,2-bond of naphthalene (Scheme 5.32). 

Methylnaphthalenes are also found in petroleum-derived feedstocks, such as pyrolysis tar from ethylene production and cat-cracker residues (see Chapter 9.2.2). The l-/2-methylnaphthalene isomer ratio, which is around 1 2.5 for methyl-naphthalenes in coal tar, is higher in this case, because of the lower temperature exposition of the raw material, and is close to 1 1. Recovery of methylnaphthalenes from these sources is generally only carried out on a small scale, since it can be extremely intricate to separate co-boiling compounds petroleum-derived methylnaphthalenes has served as a feedstock for naphthalene production by dealkylation, especially in the USA in the 1960 s and 70 s. 

Kodomari et al. [8] report the chlorination of alkoxybenzenes in chlorobenzene with copper(II) chloride on neutral alumina. The reactions are typically carried out at 100°C within 3 h, giving excellent yields and para to ortho product ratios greater than 30. Higher substituted arenes have been chlorinated with sulfuryl chloride and silica gel in hexane at room temperature [9]. 1,2,4,5-Tetramethylbenzene yields 73% of the mono-chloro product and 10% of the dichloro product. The system has been applied to a wide range of substituted benzenes and naphthalenes. 

The last example in Table 6.13 is the Friedel-Crafts acylation of naphthalene (CioHg). Substitution is found at both C-1 (C-a) and C-2 (C-P). Presumably, these products form by pathways that are similar to those already examined. However, dramatic solvent effects on the product ratio have been reported and if the acylation is carried out in solvents that can form complexes with ethanoyl chloride (acetyl... 

Irradiation of 5-fluoro-l,3-dimethyluracil and various benzophenones gives rise to mixtures of oxetanes and [2 -f 2] uracil dimers. The product ratios (oxetanes to dimers) depend on the henzophenone triplet energy levels. Kinetic analysis shows that the rate constants of the two processes are comparable. When 5-fluoro-l,3-dimethyluracil is irradiated in the presence of methoxy- and dimethoxy-naphthalene derivatives, selective formation of conjugated (arylpropenylidene)-l,3-diazin-2-ones is observed, through a pathway involving an initial Paterno-Biichi photocyclisation. ... 

The unit Kureha operated at Nakoso to process 120,000 metric tons per year of naphtha produces a mix of acetylene and ethylene at a 1 1 ratio. Kureha s development work was directed toward producing ethylene from cmde oil. Their work showed that at extreme operating conditions, 2000°C and short residence time, appreciable acetylene production was possible. In the process, cmde oil or naphtha is sprayed with superheated steam into the specially designed reactor. The steam is superheated to 2000°C in refractory lined, pebble bed regenerative-type heaters. A pair of the heaters are used with countercurrent flows of combustion gas and steam to alternately heat the refractory and produce the superheated steam. In addition to the acetylene and ethylene products, the process produces a variety of by-products including pitch, tars, and oils rich in naphthalene. One of the important attributes of this type of reactor is its abiUty to produce variable quantities of ethylene as a coproduct by dropping the reaction temperature (20—22). 

Naphthalenesulfonic Acid. The standard manufacture of 2-naphthalenesulfonic acid involves the batch reaction of naphthalene with 96 wt % sulfuric acid at ca 160°C for ca 2 h (13). The product contains the 1- and 2-isomers in a ratio of ca 15 85. Because of its faster rate of desulfonation,... 

Sulfonation can be conducted with naphthalene—92 wt % H2SO4 in a 1 1.1 mole ratio with staged acid addition at 160°C over 2.5 h to give a 93% yield of the desired product (20). Continuous mono sulfonation of naphthalene with 96 wt % sulfuric acid in a cascade reactor at ca 160°C gives... 

Polynuclear Aromatics. The alkylation of polynuclear aromatics with olefins and olefin-producing reagents is effected by acid catalysts. The alkylated products are more compHcated than are those produced by the alkylation of benzene because polynuclear aromatics have more than one position for substitution. For instance, the alkylation of naphthalene [91-20-3] with methanol over mordenite and Y-type zeoHtes at 400—450°C produces 1-methylnaphthalene [90-12-0] and 2-methylnaphthalene at a 2-/1- ratio of about 1.8. The selectivity to 2-methylnaphthalene [91-57-6] is increased by applying a ZSM-5 catalyst to give a 2-/1- ratio of about 8 (102). 

Figure 4.48 Product spectra and isomer ratios for the nitration of naphthalene with HNOj in micro reactors from different suppliers [98],...

Table IV shows the proton ratios obtained from the nmr spectra on the original fractions A, B and C and all the bottoms products. The proton ratios for the bottoms products have been adjusted to eliminate absorptions due to residual naphthalene. Note that the original fractions contained hydrogen present from combined phenol. Most of this hydrogen appears as monoaromatic hydrogen, but when the phenol-OH is still intact, one proton will appear as OH hydrogen.

The partial reduction of 9,10-dimethylanthracene gave rise to two isomers in a 6 1 ratio. The major product was the ds-isomer, and the minor product the trans-isomer. The system is not suitable for the reduction of simple aromatics such as benzene or naphthalene. The yields there were quite low with 2% and 15%, respectively. 

Because anti/syn ratios in the product can be correlated to the E(0)/Z(0) ratio of the involved boron enolate mixture,10b initial experiments were aimed at the preparation of highly E(0)-enriched boron enolate. The E(0)/Z(0) ratio increases with the bulk of the alkanethiol moiety, whereas the formation of Z(O) enolates prevails with (S )-aryl thioates. (E/Z = 7 93 for benzenethiol and 5 95 for 2-naphthalene thiol esters). E(O) reagent can be formed almost exclusively by reaction of (5)-3,3-diethyl-3-pentyl propanethioate 64 with the chiral boron triflate. High reactivity toward aldehydes can be retained in spite of the apparent steric demand (Scheme 3-22).43... 

Interpretation/report The GC retention time of a naphthalene standard and the mass spectrum of this peak confirm its presence. Because of the complexity of the chromatograms of the petroleum products and the pesticide sample, you find it impossible to examine the chromatogram of each. However, a comparison of the GC fingerprints (i.e., the matching of chromatographic peaks and comparison of peak ratios) clearly shows that the sample consists of naphthalene dissolved in kerosene. 

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