Colourants organic

There are a number of particular technical advantages associated with the formation of coloured metal complexes. Commonly, the transition metal complexes of a coloured organic ligand exhibit lightfastness which is significantly better than that of the free ligand. An explanation that has been offered for this effect is that coordination with a transition metal ion... 

Figure 1.1 A silica sol precursor doped with a coloured organic molecule.

CD Muller, A Falcou, N Reckefuss, M Rojahn, V Wiederhirn, P Rudati, H Frohne, O Nuyken, H Becker, and K Meerholz, Multi-colour organic light-emitting displays by solution processing, Nature, 421 829-833, 2003. 

Redox proteins do not usually equilibrate with a platinum metal surface and, therefore, in order to establish thermodynamic equilibrium one must add a mixture of redox mediators to the solution. These are the same strongly coloured organic dyes... 

The photographs show the structures of coloured organic compounds. 

In those climatic regions where humus is developed, it is normally found in undisturbed forested areas above the normal mineral soil. Decomposed black coloured organic material (humus) should be sampled. 

You ve already met the orange pigment p-carotene. Eleven C=C double bonds make up most of its structure. Coloured organic compounds often contain chains of C=C double bonds like this. In Chapter 7 you will find out why this is so. 

Matthews, R. W. Photooxidative Degradation of Coloured Organics in Water Using Supported Catalysts. Ti02 on Sand, Wat. Res. 1991, 25, 1169-1176. 

Bousher, A., X. Shen, and R. G. J. Edyvean (1997). Removal of coloured organic matter by adsorption onto low-cost waste materials. Water Res. 31,8, 2084-2092. 

A further considerable decrease in the concentration of residual coloured organic substances is possible after sufficient time (approximately 24 hours) by doses of coagulant exceeding the optimum for the separation at t = 0 and t = 45 minutes. 

Iodide can be determined spectrophotometrically (after oxidation to iodine), either as the blue iodine-starch adsorption compound, or as coloured organic extracts containing iodine. Iodide is oxidized to iodine with nitrite or iron(III). 

R.W. Matthews, Photooxodative degradation of coloured organics in water using supported catalysts Ti02and sand . Water Research, 25,1169-1176, (1991). 

Dark colour, Organic Or soar, siOr clOr Requires special... 

Muller, C.D., A. Falcou, N. Reckefuss, M. Rojahn, V. Wiederhim, P. Rudati, H. Frohne, O. Nuyken, H. Becker, and K. Meerholz. 2003. Multi-colour organic fight-emitting displays by solution processing. Nature 421 (6925) 829-833. 

Removal of Coloured Organics from Aqueous Solutions... 

After sulphonation is complete, water is added to the acid products to achieve separation of the alkylbenzene sulphonic acid from sulphuric acid. The "spent acid" represents the lower (high gravity) phase and consists of 78% sulphuric acid, hi y coloured material and about 0.1 - 0.2% sulphonic acids. The separation is based on the principle that many sulphonic acids are relatively insoluble in sulphuric acid of intermediate strength (i.e. about 50 -80%) obtained by suitable dilution of the reaction mixture of sulphonic acid and sulphuric acid after sulphonation with 20% oleum or 100% sulphuric acid. This 70 - 80% sulphuric acid is unlike normal sulphuric acid especially with respect to colour, organic matter and viscosity. It has generally a dark brown/black colour and a strong odour of SO2. 

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