Gasoline, polymer

When water is removed from a strong aqueous solution of phosphoric acid, (H3PO4), some dehydration of the acid takes place, and some pyrophosphoric acid is formed  

So-called 100% acid is a mixture comprising 88% orthophosphoric acid, 6% pyrophosphporic acid and 6% water. The optimum catalyst for the alkylation reaction contains 102% phosphoric acid and therefore contains an even higher concentration of pyrophosphoric acid. 

There is a small loss of water during reaction, and this must be replaced continuously by addition of water to the feed gases to maintain catalyst performance. The specifications for early polymerization catalysts are given in Table 6.2. Total phosphoric acid (wt%) is the amount of acid that has combined with the support and that cannot be extracted with cold water. The specifications of two typical dehydrogenation catalysts are given in Table 6.3 

The olefin polymerization reaction is exothermic and the reactor design depends on the olefin content of feed gas. For polygasoline production the olefin content is usually in the range 50-60% and a tube-cooled reactor is used. Temperature control is important because phosphate esters can form at temperatures below about 150°C, while at temperatures above about 230 C, thermal cracking or gum forming reactions are likely. In both cases the catalyst loses activity (Table 6.4). 

Isobutylene polymerization (solid phosphoric acid) catalyst  

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Polymer electrolyte Polymer electrolytes Polymer emulsions Polymer flocculation Polymer gasoline... 

Polymerization. In the petroleum iadustry, polymerization is the process by which olefin gases are converted to higher molecular weight Hquid products which may be suitable for gasoline (polymer gasoline) or other Hquid fuels. 

Examples of commercial metal deactivators used in polymers, gasoline, and foods are oxalyl bis(bensyhdene)hydraside [6629-10-3] (28). 

Polymer Gasoline. Refinery trends tend to favor alkylation over polymerisation. Unlike the alkylation process, polymerisation does not require isobutane. The catalyst is usually phosphoric acid impregnated on kieselghur pellets. Polymerisation of butylenes is not an attractive alternative to alkylation unless isobutane is unavailable. The motor octane number of polymer gasoline is also low, and there is considerable shrinkage ia product volume. The only commercial unit to be built ia recent years is at Sasol ia South Africa. The commercial process was developed by UOP ia the 1940s (104). 

Most of the propylene polymerized by this process is used in motor gasoline ("Polymer Gasoline"). However, an appreciable portion of the C7, C, and C,2 olefins find use as feedstocks for production of Oxo alcohols. 

This process produces polymer gasoline with a high octane. Dimerization was first used (1935) to dimerize isobutylene to diisobutylene, constituted of 2,4,4-trimethyl-1-pentene (80%) and 2,4,4-trimethyl-2-pentene (20%). Both phosphoric and sulfuric acid were used as catalysts. 

After bauxite treatment the product was fractionated to produce C3-C4 and naphtha (C5-204°C) fractions. The C3-C4 olefin-rich gas was oligomerized over a solid phosphoric acid (SPA) catalyst to produce an unhydrogenated polymer gasoline with a research octane number (RON) of 95 and MON of 82.21 The bauxite-treated FT motor gasoline (RON of 87, MON of 76) was mixed with the polymer gasoline and some natural gas condensates (and crude-oil-derived naphtha) to produce the final motor gasoline product. In this respect it is noteworthy that the Fe-HTFT-derived material was the high-octane-blend stock. 

Hydropol A process for co-hydrogenating u-butenes with olefinic gasoline fractions. Developed by the Institut Frangais du Petiole as part of its polymer gasoline process. Hydrocarbon Process., 1980, 59(9), 219. 

Selectopol A process for converting isobutene into polymer gasoline, i.e. a mixture of branched-chain C6 - C12 hydrocarbons, using an acid catalyst. Offered for license by the Institut Frangais du Petiole. 

Polymer fume fever, 18 304 Polymer gasoline, 4 423 propylene in, 20 782-783 Polymer gels, smart, 22 718 Polymer-grade ethylene, specification for, 10 624t... 

Polymer gasoline a gasoline produced by polymerization of low-molecular-weight hydrocarbons such as ethylene, propane, and butanes. It is used in small amounts for blending with other gasoline to improve its octane number. 

Ci and lighter gas Debutanized polymer gasoline Debutanized thermal reformate Residuum Product recovery... 

Polymer gasoline yields were estimated for each of the test periods, using recoveries of 70 and 95% for the C3 and C4, respectively, and a polymerization conversion of 90%. The estimated yield-octane relationship for the combination of thermal reforming and catalytic polymerization is represented by the broken line in Figures 3 and 4. 

Table I. Inspection of Typical Thermal Polymer Gasolines...

Heptenes. Heptenes, C7FL 7, are used for the preparation of isooctyl alcohol [26952-21-6] by hydroformylation (see Oxo process). The heptenes are prepared by very carefully controlled fractionation of polymer gasoline. Specifications generally call for >99.9% C content (including some paraffin that is also formed) to simplify processing. 

Refiners have a choice of using either alkylation or polymerization to synthesize gasoline from lower molecular weight hydrocarbons. Almost without exception in the last two decades, alkylation has been chosen because it produces a superior gasoline product. Alkylate does not contain olefins which require gum inhibitors or hydrogenation to improve stability, and it has a higher RON and MON than polymer gasoline. 

Polymer gasoline the product of polymerization of gaseous hydrocarbons to hydrocarbons boiling in the gasoline range. 

Ipatieff, V. N. and Egloff, G. Polymer gasoline has higher blending value than pure isooctane. Oil Gas J., 33, 1935, 31-32. 

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