Of waxes

The characteristic properties of waxes and paraffins can be grouped in three classes... 

The mechanical properties of waxes and solid paraffins are of considerable importance for most applications and numerous tests have been developed for characterizing the hardness, the brittleness, and resistance to rupture. 

A separator is fed with a condensate/gas mixture. The condensate leaves the bottom of the separator, passes a flowmeter and is followed by a choke valve, after which the condensate is boiling. The flow can not be measured using the transit time method, due to the combination of short piping, the absence of a suitable injection point and the flow properties of the condensate, which is non-newtonian due to a high contents of wax particles The condensate can not be representatively sampled, as it boils upon depressuratioh... 

Fats and oils are one of the oldest classes of chemical compounds used by humans. Animal fats were prized for edibiUty, candles, lamp oils, and conversion to soap. Fats and oils are composed primarily of triglycerides (1), esters of glycerol and fatty acids. However, some oils such as sperm whale (1), jojoba (2), and orange roughy (3) are largely composed of wax esters (2). Waxes (qv) are esters of fatty acids with long-chain aUphatic alcohols, sterols, tocopherols, or similar materials. 

Recent advances in Eischer-Tropsch technology at Sasol include the demonstration of the slurry-bed Eischer-Tropsch process and the new generation Sasol Advanced Synthol (SAS) Reactor, which is a classical fluidized-bed reactor design. The slurry-bed reactor is considered a superior alternative to the Arge tubular fixed-bed reactor. Commercial implementation of a slurry-bed design requires development of efficient catalyst separation techniques. Sasol has developed proprietary technology that provides satisfactory separation of wax and soHd catalyst, and a commercial-scale reactor is being commissioned in the first half of 1993. 

A number of chemical products are derived from Sasol s synthetic fuel operations based on the Fischer-Tropsch synthesis including paraffin waxes from the Arge process and several polar and nonpolar hydrocarbon mixtures from the Synthol process. Products suitable for use as hot melt adhesives, PVC lubricants, cormgated cardboard coating emulsions, and poHshes have been developed from Arge waxes. Wax blends containing medium and hard wax fractions are useful for making candles, and over 20,000 t/yr of wax are sold for this appHcation. 

The use of the various tempera and of wax has been identified on objects dating back to ancient Egypt. The Eayum mummy portraits are beautiful examples of encaustic painting, ie, using molten wax as medium. A rather special variation was the technique used by the Romans for wall paintings. In these, the medium, referred to by Pliny as Punic wax, probably consisted of partially saponified wax. In Europe, wax ceased to be used by the ninth century. 

Pour-Point Depressants. The pour point of alow viscosity paraffinic oil may be lowered by as much as 30—40°C by adding 1.0% or less of polymethacrylates, polymers formed by Eriedel-Crafts condensation of wax with alkylnaphthalene or phenols, or styrene esters (22). As wax crystallizes out of solution from the Hquid oil as it cools below its normal pour point, the additive molecules appear to adsorb on crystal faces so as to prevent growth of an interlocking wax network which would otherwise immobilize the oil. Pour-point depressants become less effective with nonparaffinic and higher viscosity petroleum oils where high viscosity plays a dominant role in immobilizing the oil in a pour-point test. 

Another method of separating petrolatum from residua is by centrifuge dewaxing. In this process, the reduced cmde oil is dissolved in naphtha and chilled to —18° C or lower, which causes the wax to separate. The mixture is then fed to a battery of centrifuges where the wax is separated from the Hquid. However, the centrifuge method has been largely displaced by solvent dewaxing methods as well as more modem methods of wax removal. Similar use is... 

The different types of furniture pohshes include hquid or paste solvent waxes, clear oil pohshes, emulsion oil pohshes, emulsion wax pohshes, and aerosol or spray pohshes (3). Nonwoven wipes impregnated with pohsh ingredients have been targeted at consumers who do not wish to expend the time to dust before polishing (11). Compilations of representative formulas are given in References 3, 4, 12, and 13. Paste waxes contain ca 25 wt % wax, the remainder being solvent. Clear oil pohshes contain 10—15 wt % oil and a small amount of wax, the rest being solvent. Aerosol or spray products may contain 2—5 wt % of a sihcone polymer, 1—3 wt % wax, 0—30 wt % hydrocarbon solvent, and ca 1 wt % emulsifier. The remainder is water. 

Formulas for representative floor poHshes are Hsted in References 3, 12, 13, and 25. An aqueous formula may contain 0—12 wt % polymer, 0—12 wt % resin, 0—6 wt % wax, 0.3—1.5 wt % tris(butoxyethyl)phosphate, 1—6 wt % glycol ether, and 0—1 wt % zinc, with water filling the rest. Water-clear floor finishes contain Htfle or no wax, whereas buffable products contain relatively large amounts of wax. Sealers contain Htfle wax and relatively large amounts of emulsion polymers (28). For industrial use, sealers are appHed to porous substrates to fiH the pores and prevent poHshes that are used as topcoats from soaking into the floor. 

Several types of wax and wax—metal emulsions are water repeUents (30,31). Among these are wax dispersions without metal salts and wax dispersions containing aluminum or zirconium salts. The products that do not contain metal salts are anionic emulsions of wax, used alone or in combination with durable-press resins. Specific compositions are proprietary. Their chief use is on nylon, polyester, and acetate fabrics. 

Wax usually refers to a substance that is a plastic solid at ambient temperature and that, on being subjected to moderately elevated temperatures, becomes a low viscosity hquid. Because it is plastic, wax usually deforms under pressure without the appHcation of heat. The chemical composition of waxes is complex all of the products have relatively wide molecular weight profiles, with the functionaUty ranging from products that contain mainly normal alkanes to those that are mixtures of hydrocarbons and reactive functional species. 

The composition of montan wax depends on the material from which it is extracted, but all contain varying amounts of wax, resin, and asphalt. Black montan wax may be further processed to remove the resins and asphalt, and is known as refined montan wax. White montan wax has been reacted with alcohols to form esters. The wax component of montan is a mixture of long-chain (C24—C q) esters (62—68 wt %), long-chain acids (22—26 wt %), and long-chain alcohols, ketones, and hydrocarbons (7—15 wt %). Cmde montan wax from Germany typically has a melting point of 80°C, an acid number of 32, and a saponification number of 92. 

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