2-Chloroethane properties

Alcohols and phenols are quite different from the hydrocarbons and alkyl halides we ve studied thus far. Not only is their chemistry much richer, their physical properties are different as well. Figure 17.1, which provides a comparison of the boiling points of some simple alcohols, alkanes, and chloroalkanes, shows that alcohols have much higher boiling points. For example, 1-propanol (MW = 60), butane (MW - 58), and chloroethane (MW = 65) have similar molecular weights, yet 1-propanol boils at 97"C, compared to 0.5°C tor the alkane and 12.5°C for the chloroalkane. 

Trithiadiazepine (21) was obtained with spontaneous loss of hydrogen chloride, in 30% overall yield, from l-chloroethane-l,2-bis(sulfenyl chloride) and sulfurdiimide as before (Equation (20)) <85CC396, 87JCS(Pl)21l>. The spectral properties and x-ray diffraction of (21) support a fully delocalized structure. 

Property Methylene Chloride Perchloro- ethylene 1,1,1-Tri- chloroethane Trichloro- ethylene Trichlorotri- fluoroethane... 

Properties Lt. straw clear to hazy liq. sol. in IPA, ethanol, 1,1,1-chloroethane, xylene, toluene disp. in min. spirits, hydrocarbon and chlorinated hydrocarbon soivs. insol. in water m.w. 11,500 sp.gr. 1.03 dens. 8.5 Ib/ l vise. 6500 cSt f.p. -50 F b.p. > 200 C flash pt. (PMCC) > 93 C nonionic 100% act., 31% silicone Toxicology Essentially nontoxic may cause temper eye discomfort, mild redness, dryness on direct contact no injury likely from relatively short exposure by inh. swallowing Ig. amts, may cause digestive discomfort TSCA listed... 

The term S) represents the absolute configuration seen in 8 and the term R) represents the absolute configuration seen in 9. Which structure is ( ) -1-bromo-l-chloroethane, 8 or 9 Given only the name, it is impossible to know The names R) and (S) are determined by an arbitrary (but universally accepted) set of rules. The (+) or (-) label is the specific rotation, a physical property. Therefore, if only the names R or S) are given, that information does not allow one to correlate the structure with the sign of the specific rotation. It is necessary to identify 8, isolate it, put it into a polarimeter, and then determine its specific rotation. Alternatively, the same can be done for 9. Only after the physical measurement of each named compound can specific rotation of an enantiomer be correlated with the absolute configuration of that enantiomer. This is a very important lesson for this chapter. 

The PHB is soluble in organic solvent this property leads to the effective and higher PHB extraction from cells. Several solvents such as chloroform, dichloroethane, tri-chloroethane, ethylene, hexane propanol, and acetone alcohol have been in use for isolation and purification of PHB to solubilize the PHB. The treatment of methanol or acetone to biomass, before the solvent extraction leads to denature low molecular weight proteins which enhance the purity of PHB. 

The physical properties of alcohols are quite different from the physical properties of alkanes or alkyl hahdes. For example, compare the boiUng points for ethane, chloroethane, and ethanol. 

Application of the tables - to calculate thermodynamic contributions requires knowledge of molecular geometry to determine the appropriate reduced moment of inertia. In cases where the potential barrier height is known from spectroscopic measurements, the tables may be used directly to calculate thermodynamic properties. Examples of molecules for which this procedure has been used include methanol, methanethiol, fluoroethane, 1,1-difluoroethane, 1,1,1-trifluoroethane, pentafluoro-chloroethane, chloroethane, 1,1,1,2-tetrachloroethane, pentachloro-... 

Table 7 Calculated and observed thermodynamic properties of chloroethane ...

In 1939, P. Muller discovered the insecticidal properties of dichloro-diphenyl-tri-chloroethane (DDT). High insecticidal toxicity and low mammalian toxicity made it worldwide the most successful insecticide for years. P. Muller was awarded the Nobel Prize for Medicine in 1948. Within a few years the production grew to more than 100 000 tonnes per year. It was used in huge quantities against moths, lice, mosquitos, flies, etc., many of them transmitters of diseases such as malaria, typhus, cholera. These diseases could be reduced drastically. 

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