Alkyl benzene standards

When alkylating benzene with dodecene, standard reaction conditions were a reaction temperature of 80°C and a catalyst ratio of 6 wt% catalyst over the total amount of reactants. Dodecene conversion reached 95 mol % with a selectivity of 98% towards monoalkylated products in the first 30 minutes of the reaction. In this case, benzene was used as solvent (molar ratio of benzene to dodecene = 10 1). 

Cyclic Hydrocarbons. Some of the cyclic hydrocarbons found in the CHX coal extracts are shown in Table V. They were tentatively identified by capillary GC/MS except for the naphthalenes, for which authentic standards were available. Selected ion profiles were used to detect sesquiterpenes (m/e 206, 191), sesquiterpanes (m/e 208), o alkanes (m/e 141), alkyl benzenes (m/e 191, 163), steranes (m/e 217),... 

In the early 1960s, over 19,000 municipal water systems had been identified. These systems drew surface waters for treatment into drinking water. At this time, however, federal water pollution control efforts revealed that chemical and industrial wastes had polluted many surface waterways. Thus, the 1962 standards provided the addition of more recommended maximum limiting concentrations for various substances such alkyl benzene sulfonate, barium, cadmium, carbon-chloroform extract, cyanide, nitrate, and silver. 

The percent nondistillable material was determined by using as an internal standard, an equal volume ixture of C to C n-alkyl-benzenes (See also reference 9). T-NMR spectra data were obtained as reported in reference (3). 

The analysis of BTEX and alkyl benzene compounds is performed on a GC-MS. The MSD is operated in the SIM mode. A fused-silica column with dimension of 30 m X 0.25 mm (i.e., 0.25-/rm film) is used. The temperature program used is the following 35°C for 2 min, ramp at 10°C/min to 300°C, and hold for 10 min. A standard solution composed of five BTEX compounds, six Ca-benzene compounds, two C4-, one C5-, and one Ce-benzene is used to determine the response factor relative to the internal standard dio-ethylbenzene for each target compound. 

Table 14-2. Values of Heats of Formation and of Standard Free Enerot of Formation for Several Alkyl Benzenes fob the Ideal Gaseous State ...

The coefficients of the individual groups were elose to 1. The order of the MIFS values was alltyl alcohols > alltyl benzenes > PAHs > alkanes. If the relationship between alkane log k values and their MIFS values is considered as the standard for in silica analysis and the retention is based on a hydro-phobic interaction, the retention of other types of eompounds should follow the relationship of the alkanes. The retention strength was as follows alkanes > PAHs > alkyl benzenes > alkanes, based on the MI energy values. The van der Waals energy values support the strength of hydrophobic retention. If their solvation mechanisms are the same, all eompounds should... 

N-Substituted amides can be N-alkylated by alkyl halides using a two-phase system of solid NaOH-KaCOs in refluxing benzene with tetra-n-butylammonium hydrogen sulphate as phase-transfer catalyst." This method works well for the limited range of compounds studied. Potassium t-butoxide in ether containing small amounts of a crown ether has similarly been used to N-alkylate some iV-arylbenzanilides." N-Aryl-jS-keto-amides can be N-alkylated under standard conditions (NaH-DMF-RX) after first blocking the sensitive jS-keto-amide function by formation of a difluoro-oxyborane complex with BFs-EtjO. ... 

The gas chromatographic oven was programmed from 50 to 200°C with a heating rate of 40°C min . Mixed alkyl lead standards in analytical grade benzene or methanol were added to blank traps which were run under identical conditions for calibration. 

Some of the common aromatics found in crude oil are the simple derivatives of benzene in which one or more alkyl groups (CHg) are attached to the basic benzene molecule as a side chain which takes the place of a hydrogen atom. These arenes are either liquids or solids under standard conditions. 

The equilibrium concentrations of many disubstituted benzenes (containing alkyl and halogen substituents) show that the meta isomer is in nearly all cases the most thermodynamically stable. It is not obvious why this should be so. Shine182 had discussed this problem in terms of the relative sizes of the standard enthalpy and entropy changes between any pair of isomers. 

Examples of the intermolecular C-P bond formation by means of radical phosphonation and phosphination have been achieved by reaction of aryl halides with trialkyl phosphites and chlorodiphenylphosphine, respectively, in the presence of (TMSlsSiH under standard radical conditions. The phosphonation reaction (Reaction 71) worked well either under UV irradiation at room temperature or in refluxing toluene. The radical phosphina-tion (Reaction 72) required pyridine in boiling benzene for 20 h. Phosphinated products were handled as phosphine sulfides. Scheme 15 shows the reaction mechanism for the phosphination procedure that involves in situ formation of tetraphenylbiphosphine. This approach has also been extended to the phosphination of alkyl halides and sequential radical cyclization/phosphination reaction. ... 

Fig. 2.1.2. Mass chromatograms in the SIM mode using protonated molecular ions of LAS trifluoroethyl esters, (a) LAS standard mixture and (b) LAS found in a sediment. Peak labels indicate the position of the benzene sulfonate moiety on the linear alkyl chain. Reproduced with permission from Ref. [18]. 1997 by American Chemical...

The competihve hydrogenation of alkyl-substituted arenes was also performed with lr(0) nanoparhcles [49]. Using toluene as a standard substrate, several toluene/ benzene and toluene/monoalkylbenzene hydrogenation experiments were conducted in order to determine the selectivity constants of the transition-metal nanoparticles. These selechvity constants can be used to predict the relative reactivity of any other couple of monoalkylbenzenes. A series of initial reaction... 

Figure 8.6 shows some data measured for benzene solubilized in hexadecyl pyridinium chloride. The abscissa in the figure shows the extent of solubilization expressed as moles of solubilizate per mole of surfactant. The ordinate values show shifts in the resonance frequencies from water taken as an internal standard. Shifts of peaks arising from protons in the pyridinium ring, in benzene, and in methylene groups in the alkyl tail are shown versus the extent of solubilization. 

Beside isopropyl benzene (IPB) a substantial amount of polyalkylates is formed by consecutive reactions, mostly as C6H5-(C3H7)2 (DIPB) with some C6H5-(C3H7)3 (TPB). The main reaction has a large exothermal effect, of-113kJ/mol in standard conditions. The alkylation reaction is promoted by acid-type catalysts. The synthesis can be performed in gas or liquid phase. Before 1990 gas-phase alkylation processes dominated, but today liquid-phase processes with zeolite catalysts prevail. Recent developments make use of reactive distillation. 

The synthesis of the derivatives (339)-(346) was carried out as shown in Scheme 28. Metalation of the acetal (336), followed by thiolation and alkylation, gave the ester derivative (337). Acetal deprotection to form (338) and subsequent treatment under Knoevenagel conditions with piper-idinium acetate in benzene afforded the desired ester (339). Reduction of compound (339) gave alcohol (340), which was converted to aldehyde (341) and protected as its acetal (342) under standard conditions. Deprotonation was effected by Bu"Li in THF at — 78 °C and subsequent conversion to the sulfonyl chloride was carried out by sequential treatment with sulfur dioxide and A-chloro-succinimide. Treatment of the sulfonyl chloride (343) with concentrated NH4OH in acetone provided the sulfonamide (344), which was deprotected (345) and subjected to reductive amination to provide compounds in the aminomethyl sulfonamide series (346). 

The alkylation reactions of toluene and benzene with dodecene were used as test reactions in order to evaluate the catalyst activity. It could be observed that the IL is catalytically activity after being immobilised. Moreover, due to the better dispersion of the solid catalyst in the reaction media, even the conversions obtained for the supported IL were better than for the pure IL. In the alkylation of toluene conversions reached at standard conditions were twice as high for the immobilised ILs, for benzene the difference was even bigger. 

Ionic liquids containing chloroaluminate anions are strong Lewis acids. This characteristic, coupled with the fact that they are relatively easy to handle, makes them attractive alternatives to standard Lewis and Bronsted acids such as HF. The IL can function both as a catalyst and a solvent for acid-catalyzed processes. Some of the first reactions studied in ILs were Friedel-Crafts alkylations and arylations. The [emim][Al2Cl7] affords complete conversion of benzene and acetyl chloride to acetophenone in less than 5 minutes at room temperature. 

The dipolar cycloaddition of an alkyl azide with an alkene to form an aziridine has been exploited in the total synthesis of the alkaloid ( )-aspidospermidine <20050BC213>. Enone 353 was prepared in 11 steps from 3-ethoxycyclohexenone and coupled to 2-iodo nitrobenzene under Ullman cross-coupling conditions. The acetate group of 354 was hydrolyzed and the resulting alcohol converted to an azide using standard conditions in 75% overall yield. The cycloaddition of the azide with the enone was conducted in refluxing benzene for 3 days. The fused-ring aziridine 355 was the only product isolated. None of the initial dipolar cycloadduct triazoline was observed. The... 

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