Processes paraffin/olefin process chemistry

Petrochemical-derived alcohols use a wider range of chemistry but, in each case, an olefin is the starting point. The olefins maybe derived from n-paraffins which give internal olefins, or more linear a-olefins from ethylene oligomerisation. The olefins are converted to alcohols using the oxo process (see Figure 4.16). 

Here we will describe the main aspects of the chemistry involved in selected zeolite-catalyzed processes in the field of oil refining and petrochemistry, such as short paraffin aromatization, skeletal isomerization of n-paraffins and n-olefins, isoparaffin/olefin alkylation, and catalytic cracking. 

The SMB technology was developed by UOP and its major field of application is in the area of binary separations. For example, SMB has been used in the chemical industry for several separations known as SORBEX processes [1-3], which include, among others, the PAREX process for p-xylene separation from a Cs aromatic fraction [4], the OLEX process for the separation of olefins from paraffins, the SAREX process to separate fructose from glucose [4] and the MOLEX process [5]. Simulated moving bed is being used particularly for separation of enantiomers from racemic mixtures or from the products of enantioselective synthesis [6,7]. It has been used for the production of fine chemicals, and petrochemical intermediates, such as Cg-hydrocarbons [8], food chemistry such as fatty acids [2], or certain sugars from carbohydrate mixtures [8] and protein desalination [9]. 

Multitubular reactors are mainly used in gas-phase partial oxidation processes, such as the air oxidation of light olefins, paraffins, and aromatics. Examples of chemistries where these reactors are used include the partial oxidation of methanol to formaldehyde, ethylene to ethylene oxide, ethylene and acetic acid to vinyl acetate, propylene to acrolein and acrylic acid, butane to maleic anhydride, isobutylene to methacrolein and methacrylic acid, and o-xylene to phthalic anhydride. An overview of the multitubular reactor process for the partial oxidation of n-butane to maleic anhydride is given here. 

Dimethyl sulfoxide is a favored solvent for displacement reactions in synthetic chemistry. The rates of reaction in DMSO are many times faster than in an alcohol or aqueous medium [6]. Dimethyl sulfoxide is the solvent of choice in reactions where proton (hydrogen atom) removal is the rate determining step. Reactions of this type include olefin isomerizations and reactions where an elimination process produces an olefin. Another application that uses DMSO is its use as an extraction solvent to separate olefins from saturated paraffins [7]. Several binary and ternary solvent systems containing DMSO and an amine (e.g., methylamine), sulfur trioxide, carbon disulfide/ amine, or sulfur trioxide/ammonia are used to dissolve cellulose, and act as spinning baths for the production of cellulose fibers [8,9]. Organic fungicides, insecticides, and herbicides are readily soluble in DMSO. Dimethyl sulfoxide is used to remove polymer residues from polymerization reactors. 

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