Benzene linear alkylbenzene from

Linear alkylbenzenes are made from -paraffms (Cio-Cu) by either partial dehydrogenation to olefins and addition to benzene with HF as catalyst (60%) or chlorination of the paraffins and Friedel-Crafts reaction with benzene and an aluminum chloride catalyst (40%). See Chapter 24 for more information. 

Linear alkylbenzenes are made from linear terminal olefins and benzene and are important precursors of biodegradable anionic surfactants (LAS, linear alkylbenzenesulfonates). The conventional catalyst is HF, first to be replaced by a fluorinated silica-alumina in the DETAL process. The DETAL process is safer than the HF process and also more cost-effective because no special metallurgy is required and no calcium fluoride waste stream exists.52 Zeolites such as Beta may come to the fore here because they display a higher selectivity to the desired 2-phenyl isomers.55... 

Application To produce linear alkylbenzene (LAB) from C10 to C14 linear paraffins by alkylating benzene with olefins made by the Pacol dehydrogenation and the DeFine selective hydrogenation processes. The alkylation reaction is carried out over a solid, heterogeneous catalyst in the Detal process unit. 

Friedel-Crafts technology and zeolite- or other solid catalyst-based processes are currently used for other aromatic alkylations, in particular for the manufacture of linear alkylbenzenes (LABs) made from C10-C14 olefins (Equation 8), or from the corresponding chloroparaffins and benzene, and also to make m- and p-cymene (isopropyltoluene Equation 9). LABs are used for the production of sulfonate detergents, while cymenes lead to m- and p-cresols through a procedure analogous to that used for the cumene-to-phenol process. 

Besides the production of cumene and ethylbenzene, there are a number of recent reports on the production of linear alkylbenzene, precursors to detergents, via the alkylation of benzene with C6-C18 olefins. One process uses suspension CD and essentially 100% conversion of olefin at low temperatures of 90-100°C was obtained. An HF-treated mordenite used in the alkylation of benzene and C10-C14 olefins was foimd to give a 74-84% selectivity to linear alkylbenzene containing 80% 2-phenyl isomer. A new patent on the alkylation of aromatic hydrocarbons such as benzene and cumene with straight-chain C6-C20 olefins on acidic catalyst such as zeolites or fluorine-treated zeolite catalyst packed in a Katamax-type packing was granted. A patent application on the manufacture of xylenes from reformate by RD also appeared and higher than equilibrium amounts of para-xylene were claimed. 

Linear alkylbenzene sulfonates are produced from the reaction of benzene and secondary monochloroparaffins the latter are obtained by chlorination of n-paraffins. A requirement of this process was the availability of pure n-paraffins, which was made possible by the introduction of molecular sieves. The n-paraffins can be separated with molecular sieves from kerosene or gas oil, since they have a smaller diameter (ca. 4.9 A) than the branched paraffins. 

Description. Today, the linear alkylbenzene sulfonate is the most important surfactant used. Linear chains are preferred over the branched ones due to their improved biodegradability. The reaction of linear olefins or chlorinated straight-chain paraffins with benzene in the presence of Friedel-Crafts-type catalysts (AICI3 or HF) yields linear alkylbenzene (LAB), the precursor of LAS this raw material can be procured under very attractive commercial conditions. The LAB isomer distribution depends on the type of catalyst selected. Isomers with the phenyl in the 2-position are present at about 20% and 30% in the mixture resulting from HF- and AlCls-catalyzed processes, respectively. 

Sulfonated surfactants are also powerful protease deactivators [67]. The presence of the sulfonate group on benzene makes sodium dodecyl benzene sulfonate, also called LAS (linear alkylbenzene sulfonate), more surface active than SDS. As a result, LAS is an even more efficient denaturant than SDS [27] and alcohol ethoxy sulfates [32]. For instance, in a 0.02% LAS solution, the activity of the protease from Bacillus stearothermophilus is reduced to 20% of its value in water [68]. Likewise, the subtilisin saturation by surfactants at pH 7.4 has been reported to occur at surfactant to enzyme ratios (w/w) of 6.3 (SDS) and 3.2 (LAS) [69]. 

Prior to 1965, alkylbenzene production was synthesized from petroleum tetrapropylene reacted with an aluminium chloride or hydrogen fluoride catalyst and benzene. The resultant alkylate was a hard branched-chain compound that was considered slowly biodegradable. A straight-chain alkylate, termed LAB (linear alkylbenzene), has been produced since 1965 in the United States. Extensive research has demonstrated biodegradation effectiveness in sewage treatment plants in excess of 95 percent. ... 

The linear alkylbenzene sulfonates (LABS) family is probably the world s most important surfactant family, taking into consideration their wide applicability, cost-effectiveness, and overall consumption levels. If raw-materials prices and availability (i.e., normal paraffins and benzene) remain stable, there is Utile reason to expect the situation to change in the near future. If feedstock prices increase significantly, however, alcohol sulfates and related materials derived from fat and vegetable sources may become attractive alternatives. 

Toluene in ambient air was detected using a crystal coated with carbowax 550 (35). The detector has a linear range of 30-300 ppm toluene with a relative standard deviation better than 4% and a response time of 30 sec and reversibility of less than 40 sec. No interferences were observed at 5% (v/v) level from benzene and other alkylbenzenes. Xnterfernce from water was suggested to be eliminated using nafion tubing. 

Like at low temperature coking occurs rapidly from olefins and from polyaromatics. However at high temperatures, alkylbenzenics (e.g. cumene) and branched alkanes crack rapidly, leading to olefins which are rapidly transformed into coke. Coking is slow only from the monoaromatics such as benzene or toluene and from the linear alkanes which crack slowly [10]. 

Figure 6. Log P and log k plot of alkylbenzenes and linear PAHs on a Sil-to-ODA , Sil-from-ODA , ODS-m columns for mobile phase methanol/water (90 lOv/v), flow rate 1.00 mL min, and column temperature 30 °C (1 benzene, 2 naphthalene, 3 anthracene, 4 naphthacene, 5 toluene, 6 ethylbenzene, 7 butylbenzene, 8 hexylbenzene, 9 octylbenzene, 10 decylbenzene, 11 dodecylbenzene).

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