Pure organic compound

Separations based upon differences in the physical properties of the components. When procedures (1) or (2) are unsatisfactory for the separation of a mixture of organic compounds, purely physical methods may be employed. Thus a mixture of volatile liquids may be fractionally distilled (compare Sections 11,15 and 11,17) the degree of separation may be determined by the range of boiling points and/or the refractive indices and densities of the different fractions that are collected. A mixture of non-volatile sohds may frequently be separated by making use of the differences in solubilities in inert solvents the separation is usually controlled by m.p. determinations. Sometimes one of the components of the mixture is volatile and can be separated by sublimation (see Section 11,45). 

The common gray, brown, or black flint result from admixed iron oxides or organic compounds. Pure quartz is usually colorless and transparent. The conchoidal fracture typical of flint was a boon to primitive humans, who desired clean, smooth, sharp edges that were not susceptible to uniform wear. This physical attribute and the densities of flint reflect the patterns of aggregation of its fibrous constituents. 

For pedagogical reasons, we deal only with pure organic compounds. Pure in this context is a relative term, and all we can say is the purer, the better. A good criterion of purity for a sufficiently volatile compound (no nonvolatile impurities present) is gas chromatographic homogeneity on both polar and nonpolar substrates in capillary columns. Various forms of liquid-phase chromatography (adsorption and liquid-liquid columns, thin layer) are applicable to less volatile compounds. The spectra presented in this book were obtained on purified samples. 

Ml6. McCapra, F., The chemiluminescence of organic compounds. Pure Appl. Chem. 24,611-629 (1970). 

PAC410 lUPAC Commission on the Nomenclature of Organic Compounds Pure Appl. Chem., 1983,... 

D. Bonchev, Prindples of a Novel Nomendature of Organic Compounds, Pure Appl. Chem. 55 (1983), 221-8. 

It should be noted that the bibliography refers principally to organic compounds. Purely inorganic substances such as inorganic carbides, carbonyls, carbonates, cyanides, thiocyanates are excluded even though they contain carbon. Polymers and high molecular weight compounds like proteins are excluded. 

Timmermans, J. "Physical-Chemical Constants of Pure Organic Compounds," Vol. 1-2, Elsevier, Amsterdam, 1950-65. 

Table 5.2 lists NHV values for a certain number of pure organic compounds while Table 5.3 gives values of NHVj and NHV for conventional motor and heating fuels. 

Weight net heating values NHV of pure organic compounds at 25°C and I bar abs. Sources for hydrocarbons TRC, for others DIPPR (see chapter 4). 

A further advancement in organic synthesis was the accomplishment of multi-step syntheses comprising 20 and more steps and the synthesis of rather unstable organic compounds. It was now feasible to do an experiment on a milligram scale and to separate and identify products from by-products in order to analyze them separately. The application of selective reagents or reaction conditions allowed the synthesis of enantiomerically or diastereomerically pure compounds. 

Solid organic compounds when isolated from organic reactions are seldom pure they are usually contaminated with small amounts of other compounds ( impurities ) which are produced along with the desired product. Tlie purification of impure crystalline compounds is usually effected by crystallisation from a suitable solvent or mixture of solvents. Attention must, however, be drawn to the fact that direct crystallisation of a crude reaction product is not always advisable as certain impurities may retard the rate of crystallisation and, in some cases, may even prevent the formation of crystals entirely furthermore, considerable loss of... 

It consists in treating a solution of sodium iodide in pure acetone with the organic compound. The reaction is probably of the S 2 type involving a bimolecular attack of the iodide ion upon the carbon atom carrying the chlorine or bromine the order of reactivities of halides is primary > secondary > tertiary and Br > Cl. 

MuUiken, Ideniification of Pure Organic Compounds, Volumes I-IV, 1904-1922 (J. Wiley this work is difficult to obtain in Great Britain). Huntress - MuUiken, Identification of Pure Organic Compounds, Order I, 1941 (J. Wiley Chapman and HaU). 

Some neutral compounds (e.g., methyl alcohol) cannot be salted out with potassium carbonate distillation of the saturated aqueous potassium carbonate solution frequently yields the organic compound in a comparatively pure state, or at least in sufllciently concentrated a form to enable certain derivatives to be prepared. 

Mulliken, Identification of Pure Organic Compounds, Volumes I-IV, 1904-1922 (J. WUey). 

NMR IR UVVIS and MS) were obtained using pure substances It is much more common however to encounter an organic substance either formed as the product of a chemical reaction or iso lated from natural sources as but one component of a mixture Just as the last half of the twentieth cen tury saw a revolution in the methods available for the identification of organic compounds so too has it seen remarkable advances in methods for their separation and purification... 

Isopropyl group (Section 2 13) The group (CH3)2CH— Isotactic polymer (Section 7 15) A stereoregular polymer in which the substituent at each successive chirality center is on the same side of the zigzag carbon chain Isotopic cluster (Section 13 22) In mass spectrometry a group of peaks that differ in m/z because they incorporate differ ent isotopes of their component elements lUPAC nomenclature (Section 2 11) The most widely used method of naming organic compounds It uses a set of rules proposed and periodically revised by the International Union of Pure and Applied Chemistry... 

References D. D. Wagman, et ah, The NBS Tables of Chemical Thermodynamic Properties, in J. Phys. Chem. Ref. Data, 11 2,1982 M. W. Chase, et ah, JANAF Thermochemical Tables, 3rd ed., American Chemical Society and the American Institute of Physics, 1986 (supplements to JANAF appear in J. Phys. Chem. Ref. Data) Thermodynamic Research Center, TRC Thermodynamic Tables, Texas A M University, College Station, Texas I. Barin and O. Knacke, Thermochemical Properties of Inorganic Substances, Springer-Verlag, Berlin, 1973 J. B. Pedley, R. D. Naylor, and S. P. Kirby, Thermochemical Data of Organic Compounds, 2nd ed.. Chapman and Hall, London, 1986 V. Majer and V. Svoboda, Enthalpies of Vaporization of Organic Compounds, International Union of Pure and Applied Chemistry, Chemical Data Series No. 32, Blackwell, Oxford, 1985. 

A 101.3-mg sample of an organic compound known to contain Cl is burned in pure O2 and the combustion gases collected in absorbent tubes. The tube used to trap CO2 increases in mass by 167.6 mg, and the tube for trapping H2O shows a 13.7-mg increase. A second sample of 121.8 mg is treated with concentrated HNO3 producing CI2, which subsequently reacts with Ag+, forming 262.7 mg of AgCl. Determine the compound s composition, as well as its empirical formula. 

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