Freezing and

HOCHj CHjOH. Colourless, odourless, rather viscous hygroscopic liquid having a sweet taste, b.p. 197 C. Manufactured from ethylene chlorohydrin and NaHC03 solution, or by the hydration of ethylene oxide with dilute sulphuric acid or water under pressure at 195°C. Used in anti-freezes and coolants for engines (50 %) and in manufacture of polyester fibres (e.g. Terylene) and in the manufacture of various esters used as plasticizers. U.S. production 1979 1 900 000 tonnes. 

CH3 CH0H CH20H, a colourless, almost odourless liquid. It has a sweet taste, but is more acrid than ethylene glycol b.p. 187. Manufactured by heating propylene chlorohydrin with a solution of NaHCO under pressure. It closely resembles dihydroxyethane in its properties, but is less toxic. Forms mono-and di-esters and ethers. Used as an anti-freeze and in the preparation of perfumes and flavouring extracts, as a solvent and in... 

At a given temperature and pressure, a pure compound can exist in one, two or three states. The compound exists at three different states at the triple point and at two different states along the curves of vaporization, freezing and sublimation. Refer to Figure 4.6. 

B. Widom, Interfacial Phenomena, in Liquids, Freezing and Glass Transition, Les Houches Session LI, 1989, Elsevier, 1991, pp. 507-546. 

D. W. Oxtoby, Liquids, Freezing and the Glass Transition, in Les Houches Session 51, J. P. Hansen, D. Levesque, and J. Zinn-Justin, eds., Elsevier, New York, 1990. 

Lynden-Bell R M, van Duijneveldt J S and Frenkel D 1993 Free-energy changes on freezing and melting ductile metals Mol. Phys. 80 801-14... 

Pusey P N 1991 Colloidal suspensions Liquids, Freezing and Giass Transition ed J P Hansen, D Levesque and J Zinn-Justin (Amsterdam Elsevier) pp 763-942... 

Lewis L J, Jensen P and Barrat J L 1997 Melting, freezing and coalescence of gold nanoclusters Phys. Rev. B 56 2248... 

The literature states that if one uses ice cold, concentrated sulfuric acid on a terminal alkene (a.k.a. allylbenzene) an alcohol (OH) intermediate will form Markovnikoviy on the secondary carbon (don t ask). What does this mean Let s take an example. Say one has some elemi oil and wants that elemicin that is in it. What one can do is chili, say, 500mLs of the oil to freezing and do the same for about 100-200mLs of concentrated sulfuric acid (at least 90% cone.). Next, one just mixes the two together for about 5 min. What will happen is that the cold H2SO4 will make a hydrogen... 

National Institute of Standards and Technology (NIST). The NIST is the source of many of the standards used in chemical and physical analyses in the United States and throughout the world. The standards prepared and distributed by the NIST are used to caUbrate measurement systems and to provide a central basis for uniformity and accuracy of measurement. At present, over 1200 Standard Reference Materials (SRMs) are available and are described by the NIST (15). Included are many steels, nonferrous alloys, high purity metals, primary standards for use in volumetric analysis, microchemical standards, clinical laboratory standards, biological material certified for trace elements, environmental standards, trace element standards, ion-activity standards (for pH and ion-selective electrodes), freezing and melting point standards, colorimetry standards, optical standards, radioactivity standards, particle-size standards, and density standards. Certificates are issued with the standard reference materials showing values for the parameters that have been determined. 

Halides and Oxyhalides. Vanadium(V) oxytrichloride is prepared by chloriaation of V20 mixed with charcoal at red heat. The tetrachloride (VCl is prepared by chlorinating cmde metal at 300°C and freeing the Hquid from dissolved chlorine by repeated freezing and evacuation. It now is made by chlorinating V20 or VOCl ia the presence of carbon at ca 800°C. Vanadium trichloride (VCl ) can be prepared by heating VCl ia a stream of CO2 or by reaction of vanadium metal with HCl. 

Chromium compounds number in the thousands and display a wide variety of colors and forms. Examples of these compounds and the corresponding physical properties are given in Table 1. More detailed and complete information on solubiUties, including some solution freezing and boiling points, can be found in References 7—10, and 13. Data on the thermodynamic values for chromium compounds are found in References 7, 8, 10, and 13. 

Bubble-Tube Systems The commonly used bubble-tube system sharply reduces restrictions on the location of the measuring element. In order to ehminate or reduce variations in pressure drop due to the gas flow rate, a constant differential regulator is commonly employed to maintain a constant gas flow rate. Since the flow of gas through the bubble tube prevents entiy of the process liquid into the measuring system, this technique is particularly usefiil with corrosive or viscous liquids, liquids subjec t to freezing, and hquids containing entrained solids. 

Tanks cool, contents partially freeze, and solids drop to bottom or rise to top. This case requires a two-step calculation. The first step is handled as in case 1. The second step is calculated by assuming an isothermal system at the freezing point. It is possible, given time and a sufficiently low ambient temperature, for tank contents to freeze solid. 

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