Some organic compounds

Organisms are composed of mixtures of organic and inorganic compounds. The inorganic materials have been addressed in the Chapter 2. The following is a brief introduction to organic compounds. 

Carbon atoms form bonds readily with hydrogen, oxygen, and nitrogen. Carbon also may combine with halogen elements (fluorine, chlorine, bromine, iodine), with phosphorus and sulfur, and, less often, with other elements. 

Hydrocarbons are those molecules that contain only carbon and hydrogen. This term is also used sometimes to describe any simple organic molecule, possibly with additional elements such as nitrogen, phosphorus, or oxygen. 

There are four basic kinds of organic molecules that exist in large quantities in organisms or living systems carbohydrates, lipids, proteins, and nucleotides. These combine with water, which makes up between 50 and 95% of the volume of most cells. 

Cellulose is a polysaccharide, a polymer made of glucose molecules. It is the principal structural molecule in all plants. It makes up the fibrous part of the plant s cell walls. Cellulose is flexible in young plants, which allows their cells to grow. In dead plant cells, it is usually the only compound left after dehydration. Wood is about 50% cellulose, while cotton is pure cellulose. 

A brief report of ND work on an add yttrium oxalate, Y(H502KQ04) ,-H2O, reveals a truly remarkable structure, which includes an H5O2 ion with dyad symmetry. The symmetrical hydrogen bond has O H O = 2.436(3), and 2.446(4) A in the deuteriated crystal. The absence of significant change supports the idea that the hydrogen nucleus moves in a symmetrical potential with a sin e minimum.  

Another crystal to have been studied by Y-rays and ND is gjycollic P.-G. Jonsson, Acta Cryst., 1971, B27, 893. 

A ND analysis of the complex [Ni (CsHuN20)aH ]+ Cl, HjO, which contains the cation (3) is important because of its bearing on the theory of the very short O H O bond. The intramolecular hydrogen bond is 

Cyanuric acid is another structure which has been precisely studied by. y-rays and ND. It is referred to on p. 228. 

Salicylic acid and a-resorcinol are classically important compounds in the history of X-ray crystallography. Full ND data have been collected by Bacon and Jude for the former and partial data for the latter, and the structures analysed.  

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Nitro derivatives. No general experimental details for the preparation of nitro derivatives can be given, as the ease of nitration and the product formed frequently depend upon the exact experimental conditions. Moreover, some organic compounds react violently so that nitrations should always be conducted on a small scale. The derivatives already described are usually more satisfactory for this reason the nitro derivatives have been omitted from Table IV,9. 

Table 7.16 Fluorescence Spectroscopy of Some Organic Compounds Table 7.17 Fluorescence Quantum Yield Values...

Others would include the addition of materials aimed at increa sing the bioavailabiUty of the contaminant to the degrading organisms. The most studied compounds are surfactants, but cations have been reported to increase the bioavailabiUty of some organic compounds, and sorbents and clays are also considered. The dispersion of spilled oil on water by the appHcation of dispersants is perhaps the major commercial use of this idea. 

Flame letaidancy can be impaited to plastics by incorporating elements such as bromine, chlorine, antimony, tin, molybdenum, phosphoms, aluminum, and magnesium, either duriag the manufacture or when the plastics are compounded iato some useful product. Phosphoms, bromine, and chlorine are usually iacorporated as some organic compound. The other inorganic flame retardants are discussed hereia. 

Adducts of BF and some organic compounds having labile hydrogen atoms in the vicinity of the atom bonding to the boron atom of BF may form a derivative of BF by splitting out HF. For example, P-diketones such as acetylacetone or benzoylacetone react with BF in benzene (38) ... 

Chemical Treatment. Some organic compounds are attacked by chemical reagents such as potassium permanganate, sodium hydroxide, calcium hypochlorite, and o2one (29,30). 

Scheme 1.1. Dipole Moments for Some Organic Compounds "...

Some organic compounds can be in solution with water and the mixture may still be a flammable mixture. The vapors above these mixtures such as ethanol, methanol, or acetone can form flammable mixtures with air. Bodurtha [39] and Albaugh and Pratt [47] discuss the use of Raoult s law (activity coefficients) in evaluating the effects. Figures 7-52A and B illustrate the vapor-liquid data for ethyl alcohol and the flash point of various concentrations, the shaded area of flammability limits, and the UEL. Note that some of the plots are calculated and bear experimental data verification. 

In general, near-neutral aqueous products are without action except for possible sulphide staining or, when there are dissolved salts present, some local corrosion. The slight acidity which may develop in solutions of some organic compounds such as formaldehyde or alcohols can be tolerated. 

Why are some organic compounds colored while others aren t /3-Carotene, the pigment in carrots, is purple-orange, for instance, while cholesterol is colorless. The answer involves both the chemical structures of colored molecules and the way we perceive light. 

Table 22.1 Acidity Constants for Some Organic Compounds...

Appendix A Nomenclature of Polyfunctional Organic Compounds A-1 Appendix B Acidity Constants for Some Organic Compounds A-8 Appendix C Glossary A-10 Appendix D Answers to In-Text Problems A-30... 

Whilst some organic compounds can be investigated in aqueous solution, it is frequently necessary to add an organic solvent to improve the solubility suitable water-miscible solvents include ethanol, methanol, ethane-1,2-diol, dioxan, acetonitrile and acetic (ethanoic) acid. In some cases a purely organic solvent must be used and anhydrous materials such as acetic acid, formamide and diethylamine have been employed suitable supporting electrolytes in these solvents include lithium perchlorate and tetra-alkylammonium salts R4NX (R = ethyl or butyl X = iodide or perchlorate). 

As we have seen, the primary sources of hydrocarbons are the fossil fuels petroleum and coal. Aliphatic hydrocarbons are obtained primarily from petroleum, which is a mixture of aliphatic and aromatic hydrocarbons, together with some organic compounds containing sulfur and nitrogen (Fig. 18.15). Coal is another major source of aromatic hydrocarbons. 

Charykov, A. K. Tal nikova, T.V., pH-metric method of determining the solubility and distribution ratios of some organic compounds in extraction systems, J. Anal. Chem. USSR 29, 818-822 (Engl.) (1974). 

Certain physical or chemical characteristics of the wastestream may limit the application of precipitation. For example, some organic compounds (as well as cyanide or other ions) may form organometallic complexes with metals, decreasing the precipitation potential. 

The Langmuir model has been used to describe adsorption behavior of some organic compounds at near-surface conditions.137 However, three important assumptions must be made ... 

Kuzmina and Struchkov 37) reported the structure of some organic compounds of transition metals, including triphenylstannyl derivatives of 2-dimethylamino-... 

For some organic compounds, such as phenols, aromatic amines, electron-rich olefins and dienes, alkyl sulfides, and eneamines, chemical oxidation is an important degradation process under environmental conditions. Most of these reactions depend on reactions with free-radicals already in solution and are usually modeled by pseudo-first-order kinetics ... 

The discovery of high conductivity in some organic compounds has initiated a whole era of research. The first and most used acceptor molecule is 7,7,8,8-tetracyanoquinomethane. A selenophene analog has been prepared starting from 2,5-dibromoselenophene (118) as shown in Eq. (41).151 Data for the solution electrochemistry and ESR spectroscopy of 119 and other acceptors containing dicyanomethylene units have been determined.152 In an attempt to correlate oxidation potentials with LUMO energies no obvious... 

Dreisbach, R.R., Shrader, A.A.I. (1949) Vapor pressure-temperature data on some organic compounds. Ind. Eng. Chem. 41, 2879-2880. 

Table III. Nonlinear coefficients of some organic compounds ...

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