Linear alkylbenzene alkylation

Nevertheless, such reactions catalyzed by zeolites have been discussed in the review of 2001 (1) isomerization (double-bond shift, isomerization of tricyclic molecules, like synthesis of adamantane, isomerization of terpenes, diverse rearrangements, conversion of aldehydes into ketones), (2) electrophilic substitution in arenes (alkylation of aromatics, including the synthesis of linear alkylbenzenes, alkylation and acylation of phenols, heteroarenes and amines, aromatics nitration and halogenation), (3) cyclization, including the formation of heterocycles, Diels-Alder reaction, (4) nucleophilic substitution and addition,... 

The following HF alkylation reactions are based on straight-chain olefins. A similar chemistry can be written for the branched-chain process. The main reaction is the alkylation of benzene with the straight-chain olefins to yield a linear alkylbenzene ... 

Alkylation of benzene using alpha olefins produces linear alkylbenzenes, which are further sulfonated and neutralized to linear alkylbenzene sulfonates (LABS). These compounds constitute, with alcohol ethoxy-sulfates and ethoxylates, the basic active ingredients for household detergents. Production of LABS is discussed in Chapter 10. 

Figure 10-9. The UOP (Detal) process for producing linear alkylbenzene (1) pacol dehydrogenation reactor, (2) gas-liquid separation, (3) reactor for converting diolefins to monoolefins, (4) stripper, (5) alkylation reactor, (6,7,8) fractionators.

Typical properties of detergent alkylate are shown in Table 10-2. Detergent manufacturers buy linear alkylbenzene, sulfonate it with SO3, and then neutralize it with NaOH to produce linear alkylbenzene sulfonate (LABS), the active ingredient in detergents ... 

Not only the linear Cl0-Cl8 a-olefins but also the linear C10-Cl8 olefins with internal double bonds, the so-called -v /-olefins, are of great importance in surfactant chemistry, n-a-Olefins and n-y-olefins have the same suitability for the manufacture of linear alkylbenzenes, the most important synthetic anionic surfactants, by alkylation of benzene. Nowadays medium molecular weight n- /-olefins are industrially produced by two processes the catalytic dehydrogenation of the corresponding n-alkanes [4,28] and the cometathesis of low and high molecular weight n-v /-olefins, obtained by double-bond isomerization of the isomeric n-a-olefins [29]. 

Table 1 shows the carbon chain distributions for several typical commercial alkylates. The carbon chain distributions for linear alkylbenzene (LAB) samples A, C, and E are determined by the distillation cut of n-paraffins used to make the LAB. LAB samples B and D represent blended alkylates made by mixing samples such as A and E in different ratios. This provides to the customer LAB products with a wide variety of molecular weights and improves the utilization of the fl-paraffin feedstocks. 

Table 3.5 Formation of linear alkylbenzene by Friedel Crafts alkylation.

The formation of linear alkylbenzene (LAB) by Friedel-Crafts alkylation is strongly influenced by homogeneous or heterogeneous reaction conditions (Table 3.5).7 The steric bulk of silica reduces over-alkylation and shelf life. Silica also catalyses the formation of ethers. 

Linear alkylbenzene (LAB) is produced by alkylating benzene with either alkylhalides or mono-olefins, the second option being the most widely used in commercial processes. The characteristics of final LAB, namely the isomer distribution, depend on the alkylation catalyst used HF catalyst produces a LAB known a Low 2-phenyl with a 2-phenyl isomer content around 17%, while fixed bed and A1C13 processes produce a High 2-phenyl LAB, which consists of approximately 30% of this isomer. Commercial LAB is a mixture of Ci0, Cu, C12 and Ci3 homologues with all positional isomers except the terminal one... 

Commercial linear alkylbenzene sulfonates (LAS) contain mixtures of several alkyl chain homologues each with a variable number of... 

A broad range of information pertaining to the toxicity of several classes of surfactants including anionic (linear alkylbenzene sulfonates (LAS), alkylether sulfates (AES), alkyl sulfates (AS), non-ionic (alkylphenol ethoxylates (APEO)), cationic (ditallow dimethyl ammonium chloride (DTDMAC)—a group of quaternary ammonium salts of distearyl ammonium chloride (DSDMAC)) and amphoteric surfactants (alkyl-betaines) is available. Several reviews of the scientific literature have been published [3-5,20]. 

Surfactants elimination via bile is faster in fed than in unfed fish [12,40], due to the higher secretion of bile into the digestive tract when fed. The fastest and slowest surfactants excreted were the linear alkylbenzene sulphonates (C12) and the alkyl sulphates (especially the C12-15) [12], respectively. Depuration of NP is quite rapid, 1.8-20 days in fathead minnows [32] and 4 days in the Atlantic salmon [41]. Within the same organism, differences in tissues were observed, with values of 20 h for adipose tissue and 18.5 h for muscle of rainbow trout [24]. The elimination rate of non-ionic surfactants is directly proportional to the ethoxylate unit number and inversely proportional to the alkyl chain length [33]. Average elimination rates (k2) of NPE02.8 and NP in clams were 1.8 and 1.4 per day, respectively [21], and decreasing k2 values from 0.19 to 0.001 per day were obtained from butylphenol to dodecylphenol in salmon [42]. 

Linear alkylbenzene sulfonate (LAS) and the sodium salt Na-LAS (P550), alkyl sulfate (AS) Ci2-Ci4, alkylether sulfate (AES), alcohol ethoxylate (AE) 1012/60, methylester sulfonate (MES) Ci6-Ci8, Na-lauryl sulfate, 1-octane sulfate Na, 1-decan sulfonate Na, 1-hexadecan sulfonate Na, Laurie alcohol, 1-octanol (A. Caprilico), 1-nonanol, n-decyl-alcohol, 1-undecanol, 1-tridecanol, miristic alcohol (1-tetradecanol), 1-pentadecanol, cetyl-alcohol (1-hexadecanol), 1-hep-tadecanol, estearil alcohol (1-octadecanol), nonadecanol, araquidil alcohol (1-ecosanol), heneicosanol, behenil alcohol (1-docosanol),... 

Ethylbenzene (Ethylene Alkylation), Cumene and Detergent Linear Alkylbenzene... 

Zeolite based catalysts for linear alkylbenzene production dehydrogenation of long chain alkanes and benzene alkylation. Catal. Today, 38, 243-247. 

The major uses of linear alkylbenzenes are in the manufacture of linear alkyl sulfonates, LAS, for laundry (70%), light duty dishwashing liquids (15%), industrial cleaners (12%), and household cleaners (3%). 

Doe P, El-Emary M, Wade WH, Schechter RS (1977) Surfactants for producing low interfacial tension II. Linear alkylbenzene sulfonates with additional alkyl groups. J Am Oil Chem Soc 54 570... 

Sulfated zirconia catalysts showed selectivities comparable to those of AICI3 in the alkylation of benzene with 1-alkenes to linear alkylbenzenes.396 The mesopor-ous sulfated zirconia sample could be regenerated by solvent extraction or thermal treatment. Phosphotungstic acid supported on sulfated zirconia doped with Fe proved to be very active and highly selective in the alkylation of benzene with propylene at 100-150°C to produce cumene both monoalkylation and cumene formation have better than 90% selectivity.397 It can be regenerated at moderate temperature (350°C). 

---