White seal

Several historic wax samples were analysed successfully with GALDI-MS. It was found that a group of eighteen white seals from medieval documents (thirteenth to fourteenth century) from the archive of the Canton of Lucerne (Switzerland) all mainly consisted of beeswax. For example, the mass spectrum of a white seal from 1377 (inventory no. URK636/12663) is shown in Figure 5.14b. The typical pattern of beeswax, as described for the reference sample, can be clearly recognised. An additional peak at m/z 303 may be caused by abietic acid in the form of the molecule cation (C2oH3o02, MW 302), as found for rosin (see Section 5.3.2). This hints at the use of a diterpenoid resin, which was a common hardener for beeswax. A more detailed discussion of the composition of medieval white wax seals has been published elsewhere [57]. 

Classification based on color codes is common in Europe, but is of limited value. Manufacturers have their own standards. In general, the terms silver seal and white seal indicate category A, and red seal category B. 

Normally manufactures have their own standards. The terms gold seal, silver seal, red seal, green seal and white seal are still common in Europe. 

OZIDE OZLO PASCO PERMANENT WHITE PHILOSOPHER S WOOL PROTOXTYPE 166 RED-SEAL-9 SNOW WHITE WHITE SEAL-7 ZINCITE... 

Grade American process, lead-free French process lead-free green seal red seal white seal (according to fineness) leaded (white lead sulfate) USP single crystals. 

Figure 6. Correlation images of manufactured pipe with defect, under pressure changes of (a) 20psi, (b) 30psi and (e) 40psi. The sealing rule lies to the left of the pipe and the defect zone is highlighted by the white arrow.

White C A, Johnson B G, Gill P M W and Head-Gordon M 1994 The fast multipole method Chem. Phys. Lett. 230 8-16 White C A, Johnson B G, Gill P M W and Head-Gordon M 1996 Linear sealing density funetional ealeulations via the eontinuous fast multipole method Chem. Phys. Lett. 253 268-78... 

Platinum is a beautiful silvery-white metal, when pure, and is malleable and ductile. It has a coefficient of expansion almost equal to that of soda-lime-silica glass, and is therefore used to make sealed electrodes in glass systems. The metal does not oxidize in air at any temperature, but is corroded by halogens, cyanides, sulfur, and caustic alkalis. 

In concrete, triethanolamine accelerates set time and increases early set strength (41—43). These ate often formulated as admixtures (44), for later addition to the concrete mixtures. Compared to calcium chloride, another common set accelerator, triethanolamine is less corrosive to steel-reinforcing materials, and gives a concrete that is more resistant to creep under stress (45). Triethanolamine can also neutralize any acid in the concrete and forms a salt with chlorides. Improvement of mechanical properties, whiteness, and more even distribution of iron impurities in the mixture of portland cements, can be effected by addition of 2% triethanolamine (46). Triethanolamine bottoms and alkanolamine soaps can also be used in these type appUcations. Waterproofing or sealing concrete can be accompUshed by using formulations containing triethanolamine (47,48). 

Triethylphosphine [554-70-1] M 118.2, b 100"/7mm, 127-128"/744mm, (I4 0.812, n D 1.457, pK 8.69 (also available as a l.OM sola in THF). All operations should be carried out in an efficient fume cupboard because it is flammable, toxic and has a foul odour. Purified by fractional distn at atm pressure in a stream of dry N2, as it is oxidised by air to the oxide. In 300% excess of CS2 it forms Et3PCS2 (m 118-120" cryst from MeOH) which decomposes in CCI4 to give Et3PS as a white solid m 94" when recryst from EtOH. [Sorettas and Isbell 7 Org Chem 27 273 1962 J Am Chem Soc S2 5791 I960, pK Henderson and Streuli 7 Am Chem Soc S2 5791 I960, see also trimethylphosphine.] Store in a sealed vial under N2. 

Tri-n-octylphosphine oxide [78-50-2] M 386.7, m 59.5-60°, pK jt <0. Mason, McCarty and Peppard [J Inorg Nuclear Chem 24 967 7962] stirred an O.IM solution in benzene with an equal volume of 6M HCl at 40° in a sealed flask for 48h, then washed the benzene solution successively with water (twice), 5% aq Na2C03 (three times) and water (six times). The benzene and water were then evaporated under reduced pressure at room temperature. Zingaro and White [J Inorg Nucl Chem 12 315 7960] treated a pet ether solution with aqueous KMn04 (to oxidise any phosphinous acids to phosphinic acids), then with sodium oxalate, H2SO4 and HCl (to remove any manganese compounds). The pet ether solution was slurried with activated alumina (to remove phosphinic acids) and recrystd from pet ether or cyclohexane at -20°. It can also be crystd from EtOH. 

The earliest preparation of cellulose acetate is credited to Schiitzenberger in 1865. The method used was to heat the cotton with acetic anhydride in sealed tubes at 130-140°C. The severe reaction conditions led to a white amorphous polymer but the product would have been severely degraded and the process difficult to control. Subsequent studies made by Liebermann, Francimont, Miles, the Bayer Company and by other workers led to techniques for controlled acetylation under less severe conditions. 

A. Triphenylmethylphosphonium bromide. A solution of 55 g. (0.21 mole) of triphenylphosphine dissolved in 45 ml. of dry benzene is placed in a pressure bottle, the bottle is cooled in an ice-salt mixture, and 28 g. (0.29 mole) of previously condensed methyl bromide is added (Note 1). The bottle is sealed, allowed to stand at room temperature for 2 days, and is reopened. The white solid is collected by means of suction filtration with the aid of about 500 ml. of hot benzene and is dried in a vacuum oven at 100° over phosphorus pentoxide. The yield is 74 g. (99%), m.p. 232-233°. 

Coloured smoke devices Sealed table bombs White smoke devices... 

A reaction vessel explosion at BASF s resins plant in Cincinnati (July 19, 1990) killed one and injured 71. The BASF facility manufactures acrylic, alkyd, epoxy, and phenol-formaldehyde resins used as can and paper-cup liner coatings. The explosion occurred when a flammable solvent used to clean a reaction vessel vented into the plant and ignited. The cleaning solvent that was not properly vented to a condenser and separator, blew a pressure seal, and fdled the 80-year-old building with a white vapor cloud. 

Dodge, F. T., White, R. E., and Bankler, T. 1998. Risk Assessment of Liquid Seals in Marine Vapor Control Systems. Final Report, SWRl Project No. 04-8954, Southwest Research Institute, San Antonio, TX (June 1998). 

Oxoacid salts of Ge are usually unstable, generally uninteresting, and commercially unimportant. The tetraacetate Ge(OAc)4 separates as white needles, mp 156°, when GeCl4 is treated with TlOAc in acetic anhydride and the resulting solution is concentrated at low pressure and cooled. An unstable sulfate Ge(S04)2 is formed in a curious reaction when GeCl4 is heated with SO3 in a sealed tube at 160° ... 

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