Solid paraffin test

The oil must pass the solid paraffin test at 0°C (this is essentially a cloud point test) by remaining clear at this temperature. This is established in the dewaxing step. 

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. 

If an individual generator is desired, a Pyrex test-tube (150 x 20 mm) charged with Aitch-tu-ess or an equivalent mixture (essentially an intimate mixture of a solid paraffin hydrocarbon, sulphur, and asbestos) is utilized this yields hydrogen sulphide when heated by a micro burner and the evolution of gas ceases (but not usually abruptly) when the source of heat is removed. The test-tube type of generator is depicted in Fig. 11.28. The small hole (vent) is covered... 

Fatty Oil, etc.—Mixtures of colophony (or other resin, especially copal) with resinates, oleates and linseed oil are sold for the preparation of varnishes, and mixtures of colophony with mineral oils, resin oils, fatty oils, solid fats, paraffin wax, ceresine or wax for use as brewers pitch. For the recognition of such mixtures, the following tests may be made. 

The stability of the Pu product was tested by dividing the solution into two equal portions, washing one portion with 1 vol % n-paraffin, and leaving the other untreated. Within 24 hr, solids formed in the unwashed portion of solution. No solids formed in the n-paraffin washed portion for more than a month. The solids were not analyzed, but are believed to be Pu DBP compounds formed by radiolytic decomposition of dissolved and entrained TBP. 

NOTES.—(d) When aromatic compounds bum they produce a large amount of soot. Soot is also formed when unsaturated compounds and paraffin derivatives which contain alkyl radicals with four or more carbon atoms are burned. The simpler paraffin derivatives do not produce soot on burning. The behavior of an unknown substance on ignition is frequently determined as a preliminary test in its identification. The test is best made by putting some of the liquid or solid on a small roll of copper gauze, to which a piece of wire is attached to serve as a handle. 

The cloud point (ASTM D-2500, IP 219) of lubricating oil is the temperature at which paraffinic wax, and other components that readily solidify, begin to crystallize out and separate from the oil under prescribed test conditions. It is of importance to know when narrow clearances might be restricted by accumulation of solid material (for example, oil feed lines or filters). 

Fibreboard kegs can be used for solid bulk drug, bulk tablet, or bulk excipient containment and transport. These are made up of multiple plies of test or Kraft liner board, convolutedly wound on a mandrel and bonded with sodium silicate adhesive between the plies. There may be an LDPE or other inside liner and the exterior may also be varnished. The base could be of either metal or plain thick board, the latter waterproofed by dipping into paraffin wax. 

FIGURE 8.8 Critical surface tensions of wetting of the solids polyfmethyl methacrylate) (o) and paraffin wax ( ) using test liquids of various surface tensions y -. According to Wu the maximum of corresponds to the surface tension of the solid. (Adapted from Wu, S., Polymer Interface and Adhesion, Marcel Dekker, New York, Chapter 5, 1982.)... 

Tests for the quality of the solid lubricants can be conveniently carried out by flow adsorption microcalorimetry whereby the ratio of the basal planes to the polar sites can be determined, and the affinity of the basal planes for n—paraffins, as well as the affinity for transition metal ions can both be confirmed. The samples with excessive amounts of edge sites are not likely to be acceptable for lubrication [51, 52]. 

Severe paraffin and asphaltene damage may require repeated treatment or sequences of treatment and flowback. This is because dissolution of deposited solids may be inefficient or slow, requiring repeated efforts. Also, a soak time ranging from 2 to 24 hours may be required in order to slowly solubilize deposits effectively before flowing back. Typical soak periods are from 4 to 8 hours. The higher the temperature is, the less soak time will be required. Laboratory testing can be performed to determine the necessary soak time. 

This test method covers the determination of total sulfur in liquid petroleum products and in solid petroleum products that can be liquefied with moderate heating or dissolved in a suitable organic solvent. The applicable concentration range will vary to some extent with the instrumentation used and the nature of the sample. Optimum conditions will allow the direct determination of sulfur in essentially paraffinic samples at concentrations exceeding 0.0010 mass %. 

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