Paraffins linear alkylbenzene production

Other sources of by-product HCl include allyl chloride, chlorobenzenes, chlorinated paraffins, linear alkylbenzene, siHcone fluids and elastomers, magnesium, fluoropolymers, chlorotoluenes, benzyl chloride, potassium sulfate, and agricultural chemicals. 

Linear paraffins in the C q to range are used for the production of alcohols and plasticizers and biodegradable detergents of the linear alkylbenzene sulfonate and nonionic types (see Alcohols Plasticizers Surfactants). Here the UOP Molex process is used to extract / -paraffins from a hydrotreated kerosine (6—8). 

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. 

The main use of n-paraffins is in the production of linear alkylbenzenes (90%) for the detergent industry. The other uses are solvents and lubricants (7%) and chlorinated paraffins (3%). 

In the mid-1960s, commercial processes were developed for the production of linear paraffins. These could be used as feedstock to produce linear alkylbenzene sulfonates (LAS), a biodegradable alternative to SDBS. " The majority of synthetic detergent plants built after the 1970s were for the production of LABs rather than DDB. Reformulation with LAS started the phaseout of DDB, and by the end of the 1990s, most DDB plants were no longer in operation or had been converted to production of LAB. 

Application Efficient low-cost recovery and purification processes for the production of linear alkylbenzene (LAB)-grade and/or high-purity normal-paraffin (n-paraffin) products from kerosine. 

During the early 1960s, linear aliphatic olefins, such as a olefins produced via ethylene oligomerization or linear internal olefins produced via catalytic dehydrogenation of linear paraffins, replaced the use of propylene tetramers ia iadustrialized countries, and production of more biodegradable linear alkylbenzene sulfonates (LABS) began (see ADSORPTION, LIQUID SEPARATION) (70). Except ia a few parts of the world, the use of DDES was phased out by 1980. 

The separation of linear and branched alkanes is also of importance in the process known as dewaxing, in which the removal of normal alkanes makes the product hydrocarbon less viscous and reduces the so-called pour point temperature. Such processes can be combined with catalytic isomerisations to optimise the value of oil fractions (Chapter 8). Linear paraffins are also separated using a zeolite-based process from kerosene fractions to give reactants for the synthesis of linear alkylbenzene sulfonate anionic surfactants, which are both cost effective and biodegradable. 

The use of highly branched olefins to alkylate benzene has totally given way to the production of (secondary) linear alkylbenzene (LAB), by alkylation with a linear olefin or a chlorinated paraffin, to achieve biodegradability. The LAB is subsequently sulphonated to produce a linear alkylbenzenesulphonate (LAS, as the sodium salt), the workhorse of the detergent market with a worldwide production of about 2 Mt per annum. 

Aikyiated Aromatics At present, the only products in this category are linear alky-benzenes. As is the case with the linear paraffins, they are high in purity and low in color and odor. They are less volatile and more compatible than the linear paraffins. They are also used to reduce the viscosity of plastisols. Because the viscosity of dode-cylbenzene is about four times that of a Cjs linear aliphatic hydrocarbon, it is about 25 percent less effective in reducing plastisol viscosity. Often, linear alkylbenzenes are available in blends with linear paraffins. 

In contrast to sulfation, sulfonation is not of great importance to RR-based products. Sulfoacids are made mainly from linear alkylbenzenes, paraffins and olefins, which are all important feedstocks for bulk - surfactants. 

Paraffin sulfonates, or secondary n-alkylsulfonates, are mostly a European product prepared by the sulfoxidation of paraffin hydrocarbons with sulfur dioxide and oxygen under ultraviolet irradiation. They are used in applications similar to those of the linear alkylbenzene sulfonates (LABS) discussed below. It has been suggested that the paraffin sulfonates have higher water solubility, lower viscosity, and better skin compatibility than do the LABS of comparable chain length, although any such direct comparison must be qualihed because of the distinctly different chemical and isomeric contents of the two classes of materials. 

The linear olefins are used in the production of biodegradable detergents. The Cq to cuts are fed to alkylation units where the olefins react with benzene to form alkylbenzenes which are subsequently sulphonated. The paraffins present in the feed pass through unconverted. These are then chlorinated and used as plasticizers. The linear olefins can also be converted to linear aldehydes and alcohols by hydroformylation. 

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