1.0 Introduction 1
2.0 Literature review 6
3.0 Materials and preparation 17
4.0 Result 22
References 26
CHAPTER ONE
1.0 INTRODUCTION
The tissue of wood, bark and leaves of trees contain a great variety of chemical substances of considerably scientific interest and some of the practical values. Tannin is a generic name for widely occurring group of substances of vegetable origin.
Tannins from the bark, wood and leaves of certain species of plants is one of the most important commercial extractives which also form the basis of some important industries. The main local source of obtaining industrial vegetable tannin in Acacia nilotica pods, obtained principally around Kano and Maiduguir. Due to ever increasing demand for this materials by the producers of particle boards and leathers, there has grown a scarcity which normally manifest itself in the cost of materials.
Even in the southern parts of Nigeria where new leather industries are developing, the problem of obtaining transporting and storing these pods cannot for too long be over – looked there is therefore the need for a search into other alternatives in order to avoid a heavy drain on foreign exchange because of the importation of synthan (synthetic phenolic polymers).
Again the mangrove (Rhizophora species) found largely in most tropical coast lines contain reasonable amount of tannin. But when used in the heavy tanning industries. They a re known to produce an extract which has the major set back because of its hard red colour, which is prone to further darkening on exposure to sunlight during drying Fasina (1974) suggested that after full tannage is achieved, that the leather or particle board is bleached and then retanned using a light coloured fast penetrating vegetable tannin extract. But one cannot over look here, the cost factor, since an industry is usually profit motivated.
This project is therefore an investigation carried out the determine other sources of vegetable tannin of commercial importance and which can sustain the available tanners industries in the country that is the species (bark and leaves) investigated were Pterocarpus Osun Pterocarpus Soyaureii. Burkea africana and Khaya senegalensis.
1.1 STATEMENT OF PROBLEM
For too long, there has been the importation of synthan (synthetic phenolic polymers) which is a heavy drain on foreign exchange. The importation adds much to the cost factors of the materials which tannin can be used for, thereby decreasing the profits of the products. This factor lowers the growth of some tanning industries, since industries are usually profit oriented.
Again, mangroves Rhizophora species contain a reasonable amount of tannin which has a major set back, even cacia nilotica pod is a good source of tannin but it is very for away. That is Kano and Maidguri.
Due to ever increasing demand for this material (tannin) by t
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