Original sources of chemical information

Chemical Properties. Because no single source contains information on all relevant properties, information from a variety of sources is contained in these databases. Accordingly, all entries are referenced to the original source of the information. 

The use of seaweed as a source of chemicals needed by man is not recent. The practice originated as far back as the beginning of the eighteenth century. In more recent years. The Scottish Seaweed Association has sponsored extensive studies to provide basic information upon which an industry using seaweed as the raw material could be based (Woodward, 1951). 

The original sources of information on specific items can usually be located in Chemical Abstracts in which they are indexed under Carbon, active and also under Charcoal, active. 

The objective of the present review is to present an assessment of the sources of published thermodynamic data in order to decide on the most reliable values and their uncertainties that can be recommended for modelhng purposes. Experimental measurements pubhshed in the scientific literatrrre are the main somce for the selection of recommended data. Previous reviews are not neglected, since they form a valuable source of critical information on the qrrality of primary publications. When necessary, experimental source data are re-evalrrated by using chemical models which are either foimd to be more realistic than those used by the original author, or are consistent with subsequent information, or with side-reactiorts discussed in another section of the review (for example, data on carbonate and hydroxide solubilities might need to be reinterpreted to take into accormt the crystal stractrrre and particle size of the phases actually investigated). 

As quite a number of reactions are, like other chemical information, first, or only, published in patents, these are an important source of reaction information, even though one would normally assume that new synthetic methods would also be published in the journal literature. Since 1991, reactions taken from patents have been included in CASREACT patents comprise less than 10% of the CASREACT database in 1997, compared to about 16% of the CA database. CrossFire plus Reactions contains many reactions from patents registered before 1980, when Beilstein ceased to index patents. About 14% of the reactions in CRDS/JSM and 10% of those in ChemReact originate from patents CCR includes only US patents, which contribute about 10% of the reactions and Cheminform covers no patents at all. 

The principal source of structural information in high-resolution NMR spectroscopy is the chemical shift, which originates from the shielding of the spin nucleus from the external magnetic field by the small magnetic field induced by the motions of the electrons surrounding the nucleus. Thus, the nucleus experiences an effective field, B = (1 - c)Bq, where n, the shielding constant, is a dimensionless number, usually listed in parts per million. This leads to a small modification of the resonance condition in Equation 6.1 ... 

This chapter lists some representative examples of biochemicals and their origins, a brief indication of key techniques used in their purification, and literature references where further details may be found. Simpler low molecular weight compounds, particularly those that may have been prepared by chemical syntheses, e.g. acetic acid, glycine, will be found in Chapter 4. Only a small number of enzymes and proteins are included because of space limitations. The purification of some of the ones that have been included has been described only briefly. The reader is referred to comprehensive texts such as the Methods Enzymol (Academic Press) series which currently runs to more than 344 volumes and The Enzymes (3rd Edn, Academic Press) which runs to 22 volumes for methods of preparation and purification of proteins and enzymes. Leading referenees on proteins will be found in Advances in Protein Chemistry (59 volumes. Academic Press) and on enzymes will be found in Advances in Enzymology (72 volumes, then became Advances in Enzymology and Related Area of Molecular Biology, J Wiley Sons). The Annual Review of Biochemistry (Annual Review Inc. Patio Alto California) also is an excellent source of key references to the up-to-date information on known and new natural compounds, from small molecules, e.g. enzyme cofactors to proteins and nucleic acids. 

If you supply chemicals to others, whether you are a manufacturer or distributor, you obviously need to provide your customers with the data they need to safely handle any reactive materials. Do not use published data indiscriminately. If possible, track down and consider the original source. It may be necessary to have your own testing performed, if the available sources of data are questionable or your own experience indicates that testing may be warranted. Your customers may be looking to you as the first and best source of data and information on the reactive properties of your products. 

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