Alkylation and Polymerization

In polymerization an olefin can react with another olefin to generate dimers, trimers, and tetramers of the olefin. As a simple example, isobutylene reacts to give a highly branched Cg olefin. 

In general, polymerization gives an average RON of 94 alkylation gives 95. 

A simplified schematic for natural gas separation is given here and consists of the following steps. 

Dehydration by passing through diethylene glycol, in which water is very soluble. 

Elimination of hydrogen sulfide and carbon dioxide with aqueous mono- or diethanolamine. 

Alkylation generates relatively low volumes of wastewater, primarily from water washing of the liquid reactor products. Wastewater is also generated from steam strippers, depropanizers, and debutanizers, and can be contaminated with oil and other impurities. Liquid process waters (hydrocarbons and acid) originate from minor undesirable side reactions and from feed contaminants, and usually exit as a bottoms stream from the acid regeneration column. The bottoms stream is an acid-water mixture that is sent to the neutralizing drum. The acid in this liquid eventually ends up as insoluble calcium fluoride. 

A basic step in hydrofluoric acid manufacture is the reaction of sulfuric acid with fluorspar (calcium fluoride) to produce hydrogen fluoride and calcium sulfate. Spent alumina is also generated by the defluorination of some hydrofluoric acid alkylation products over alumina. It is disposed of or sent to the alumina supplier for recovery. Other solid residuals from hydrofluoric acid alkylation include any porous materials that may have come in contact with the hydrofluoric acid. 

---

To obtain light ends conversion, alkylation and polymerization are used to increase the relative amounts of liquid fuel products manufactured. Alkylation converts olefins, (propylene, butylenes, amylenes, etc.), into high octane gasoline by reacting them with isobutane. Polymerization involves reaction of propylene and/or butylenes to produce an unsamrated hydrocarbon mixture in the motor gasoline boiling range. 

The cat products become feed to other units, such as alkylation and polymerization plants. High boiling liquid products are used to make lubes, and the gas goes into the refinery fuel systems. Cat cracking feed stocks come from atmospherie and vacuum stills, phenol extraction plants, hydrotreaters, deasphalters and cokers. 

Through the 19.30s, Ipatieff led UOP in its effort to develop two catalytic processes for the production of high-octane fuel alkylation and polymerization— the first, a reaction of a hydrocarbon with an olefin (double-bonded compound) the second, the formation of long molecules from smaller ones. Both processes produce high-octane blending compounds that increase the quality of cracked gasoline. 

Catalytic conversion processes include naphtha catalytic reforming, catalytic cracking, hydrocracking, hydrodealkylation, isomerization, alkylation, and polymerization. In these processes, one or more catalyst is used. A common factor among these processes is that most of the reactions are initiated hy an acid-type catalyst that promotes carhonium ion formation. 

Catalyst in alkylation and polymerization reactions Additives to liquid rocket fuels Uranium refining Cyclosarin (GF) 9.01... 

Fluorosulfonic acid can be used in fluorination reactions, and it functions as a catalyst in reactions such as alkylation and polymerization. One of the most important uses of FS03H and C1S03H is as sulfonating agents to introduce the -S03H group into various organic materials. 

Propylene is manufactured by steam cracking of hydrocarbons as discussed under ethylene. The best feedstocks are propane, naphtha, or gas oil, depending on price and availability. About 50-75% of the propylene is consumed by the petroleum refining industry for alkylation and polymerization of propylene to oligomers that are added to gasoline. A smaller amount is made by steam cracking to give pure propylene for chemical manufacture. 

Much of the propylene is consumed by the petroleum refining industry for alkylation and polymerization to oligomers that are added to gasoline. A smaller amount is used for chemical manufacture. 

Hydrogen chloride is an important industrial chemical. The anhydrous form is used in making alkyl chlorides and vinyl chloride from olefins and acetylene, respectively, and in hydrochlorination, alkylation, and polymerization reactions (Sax and Lewis 1987). The hydrated form of hydrogen chloride is hydrochloric acid, which also is used in idustrial processes. 

Liquid-liquid systems with mechanical agitation are widely employed by the chemical industry to carry out chemical reactions like nitration, alkylation, and polymerization to prepare emulsions and to perform a variety of extraction, washing, and other operations involving transfer of material from one liquid phase to another. The literature on these systems is limited, and the many different liquids used by different investigators make it difficult to compare the published studies. As in the... 

As the ion concentration in the acid grows toward a steady state value, alkylation and polymerization-cracking reactions occur which generate a distribution of C5" " to Cg" " ions in the acid. An estimate of this "homogeneous" alkylate distribution in the bulk acid can be made from the product distribution at the earliest times shown in Figures 8 to 11. 

There is some disagreement as to how firmly metal alkyls are adsorbed on titanium trichloride. Keii et al. [112] state that AlEtj is removed by washing with hydrocarbon solvent with loss of polymerization activity which is restored by the addition of further AlEts- Natta [81] found that washed catalyst contained substantial amounts of adsorbed aluminium alkyl and retained its polymerization activity. Chien [86] likewise concluded that treatment of TiCl3 with AlEtjCl resulted in surface alkylation. With the precipitates from TiCl4 and aluminium alkyls there are similar discrepancies. Most data (Table 1) show the presence of substantial amounts of adsorbed alkyl, but Saltman et al. [41] and Tepenitsyna et al. [225] both reported that washing with hydrocarbon solvent removed adsorbed aluminium alkyl and polymerization activity. ... 

The regenerated carbonium ion can of course continue the process, a key feature being that under alkylation conditions this active species is formed from saturated alkane, not an olefin as required by polymerization. Different alkenes, such as propylene, 1-butene, or the 2-butenes may also form carbonium ions in a similar manner to the process of Eq. 18.25. However, neither /7-butane nor /7-pentane can replace an isoalkane for the hydride transfer since an /7-alkane is not capable of forming a stabilized carbonium ion. Nevertheless, this is one advantage that the alkylation process has over polymerization as a route to gasoline it is able to use both light hydrocarbon alkanes (as long as they are branched) and alkenes. Alkylation and polymerization both produce branched products, but the alkylation products are saturated (Table 18.5) whereas the polymerization products are alkenes. 

Because of its electron-accepting power, boron trifluoride is an excellent catalyst for many reactions such as alkylations and polymerizations. It is prepared in considerable quantities for use in the petroleum and synthetic organic chemical industries. 

The papers of Whitmore ( ) proposed a carbonium ion as the intermediate in low-temperature acid-catalyzed reactions such as alkylation and polymerization the same intermediate could perhaps be involved in catalytic cracking. 

The manufacturing process for partially alkylated amino formaldehyde resins consist of two consecutive reactions. The first reaction is the methylolation (hydroxy-methylation) of an amino compound such as urea, melamine, or benzoguanamine with formaldehyde and can be carried out under basic or acidic conditions. Hydroxy-methylation under acidic conditions leads to simultaneous alkylation and polymerization of the amino resin. The second reaction, alkylation (or etherification), is carried out under acidic conditions. 

The fully alkylated amino resin is characterized by its degree of alkylation and polymerization, and its residual hydroxymethyl and amino content, all of which can significantly affect physical and chemical properties. 

Combining processes. Two processes, alkylation and polymerization, are used to produce gasoUne-blending stocks from the gaseous hydrocarbons formed during cracking processes. 

---