ORGANICS CHARACTERISATION

Hummel T., Kiihnau D., Knecht M., Abolmaali N. and Huttenbrink K.B. (1999). The anatomy of the vomeronasal organ characterisation by means of nasal endoscopy and magnetic resonance imaging. Chem Senses 24, abs. 365. 

Rejection of natural organics by UF membranes has been discussed briefly in the natural organics characterisation and size fractionation by UF section of Chapter 2. The MWCO ranges from 0.5 to 300 kDa in UF and this governs retention of natural organics. 

Mallevialle et al. (1989) described a range of surface analytical techniques that are available for foulant identification. Many techniques that are currently being used for organics characterisation (see Chapter 2) can potentially be used for membrane deposit characterisation. 

Further characterisation is reported in the organics characterisation section below. An overview over some characteristics is also shown in Chapter 2. The organics were prepared as 100 mgL organic carbon stock solutions by mixing the dry powder with MilliQ water without increasing the pH. The solutions were stored at 4 C in the dark. The amount of powder required for 100 mL stock solution was 18.4 mg, 18.6 mg and 200 mg for HA, FA and NOM respectively. This reflects the carbon content of the organics. 

An extensive literature review on organics characterisation lead to the conclusion that a combination of MF and RO followed by freeze drying is the state of the art technique to concentrate surface water to produce a stock of natural organic matter (NOM). This technique was applied to concentrate 5000 L of a local Australian surface water. Further, model compounds of the surface water systems to be examined were selected. These are well characterised and purified organics (IHSS FA FIA), and inorganic colloids (40 - 500 nm in diameter) in a carbonate buffer system containing mono- and multivalent cations. 

Hydrazine and its alkylated derivatives are used as rocket fuels in organic chemistry, substituted phenylhydrazines are important in the characterisation of sugars and other compounds, for example aldehydes and ketones containing the carbonyl group C=0. 

Phenylhydrazine on exposure to light slowly darkens and eventually becomes deep red in colour salts of the base share this property but to a lesser degree, the sulphate and acetate (of the common salts) being most stable to light. Phenylhydrazine is largely used in organic chemistry to characterise aldehydes and ketones as their phenyl-hydrazones (pp. 342, 345), and carbohydrates as their osazones (pp. 136-140). It is readily reduced thus in the process of osazone formation some of the phenylhydrazine is reduced to aniline and ammonia. On the... 

The number of quinones normally encountered in routine quahtative organic analysis is very limited the following notes will be found useful for their detection and characterisation. 

The experimental details already given for the detection and characterisation of aliphatic esters (determination of saponification equivalents h3 diolysis Section 111,106) apply equally to aromatic esters. A sfight modification in the procediu-e for isolating the products of hydrolysis is necessary for i)henolic (or phenyl) esters since the alkaline solution will contain hoth the alkali phenate and the alkali salt of the organic acid upon acidification, both the phenol and the acid will be hberated. Two methods may be used for separating the phenol and the acid ... 

In addition to inorganic radicals, which profoundly modify the properties of a paraflSn hydrocarbon residue, there is a whole series of organic groupings which are distinguished by exceptional reactivity, for example, the ethylene and acetylene groupings, and the phenyl and naphthyl radicals. Thus the characterisation of unsaturated hydrocarbons and their derivatives, e.g., the aromatic compounds, becomes possible. 

In addition to water and ether, the following reagents are employed as solvents for the characterisation of organic compounds 5 per cent, aqueous solutions of hydrochloric acid and of sodium hydroxide, and also concentrated sulphuric acid. 

The methods of preparation of some of the more important derivatives of a number of classes of organic compounds are described in the various Sections dealing with their reactions and characterisation. These Sections conclude with tables incorporating the melting points and boiling points of the compounds themselves, and also the melting points of selected derivatives. For convenience, the references to the various tables are collected below. 

The beneficial effect of water in the arene - arene interaction can be explained by the fact that this solvent is characterised by a low polarisability so that interactions of the aromatic rings with water are less efficient than with most organic solvents. Also the high polarity of water might lead to a polarisation of the aromatic rings, thereby enhancing electrostatic interactions. Finally, hydrophobic interactions may be expected to play a modest role. 

Organosols (Mix B, Table 12.5) are characterised by the presence of a volatile organic diluent whose function is solely to reduce the paste viscosity. After application it is necessary to remove the diluent before gelling the paste. Organosols are therefore restricted in use to processes in which the paste is spread into a thin film, such as in the production of leathercloth. Because of the extra processes involved, organosols have not been widely used, in Europe at least. 

The ceramic membrane has a great potential and market. It represents a distinct class of inorganic membrane. In particular, metallic coated membranes have many industrial applications. The potential of ceramic membranes in separation, filtration and catalytic reactions has favoured research on synthesis, characterisation and property improvement of inorganic membranes because of their unique features compared with other types of membrane. Much attention has focused on inorganic membranes, which are superior to organic ones in thermal, chemical and mechanical stability and resistance to microbial degradation. 

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