Tuesday, January 26, 2016

Hobby Pays Off For W.F. Pond, Member #13

Many people who come to love the hobby of wood collecting have professional backgrounds in which a knowledge of wood science is tangential to their work. Here's an example of how one such early member of IWCS used his knowledge of wood chemistry to drive the development of a new product for his company. By William F. Pond, from Volume 2, Number 11 (1949) of the Bulletin of the Wood Collectors Society.

Several people have asked me at times; "Bill, what pleasure can you get out of collecting a few old sticks of wood?" They do not know of the intense pleasure of collecting a "few old sticks of wood." If they did, I might wake up some morning and find my holly, mimosa, and dogwood trees had been cut during the night. Neither do these people know how my knowledge of trees and wood, meager as it is, was recently of the utmost value to me in my daily work.

Last year, it was found, quite by accident, that a certain inorganic chemical we manufacture when used in conjunction with certain of the natural tannins and saponins, greatly reduced the deposition of scale in boilers in condenser tubes. Scale is the enemy of efficient boiler operation. The typical boiler scale consists largely of calcium sulfate, calcium carbonate, magnesium sulfate, magnesium carbonate, along with some silica, and the oxides of iron and manganese. Deposited as a hard, tenacious scale, this pest results in lowered heat transfer, more fuel consumption, not to mention corrosion.

The discovery seemed so fraught with possibilities, it was assigned to my department as a research project. Several hundred gallons of various hard waters were obtained for this study. These waters were notoriously bad actors. Several of the various tannins and saponins were obtained and the study started.

A period of eight months was spent on this study, during which period some three hundred laboratory experiments were carried out. Many gallons of water containing various combinations of chemicals were greatly reduced in volume by boiling and the nature of the scale examined. At the end of the eight months period, the outlook was very favorable, so operations were started on a pilot plant scale, which confirmed the favorable results obtained in the laboratory. Naturally, our thoughts next turned toward a patent, and here especially, is where my smattering of botany came to the rescue. Before we cover this, however, let's take a look and see how botany, (especially dendrology) entered the picture from the first.

The tannins are astringent, aromatic compounds, acid in character. These tannins precipitate the alkaloids, mercuric chloride, and the heavy metals. Added to solutions of ferric compounds, they form black or blue inks. Dissolved in strong alkalies, as caustic potash, they are excellent oxygen absorbers. The best known and commonest tannin is tannic acid, which chemically, is penta-digalloyl glucose, C14H10O9. Gallotannic acid, C76H52O46 is a closely related body. The list of tannins is quite lengthy; a few more may now be mentioned:

di-beta-resorcylic acid
hamamelitannin
ipecacuanhic acid
fraxitannic acid
m-digallic acid
Maclurin
Quercin

Chemically, these tannins are therefore compounds, containing several benzol rings hooked up with a monosaccharide. The chemistry of the tannins is far from complete and frequently new data becomes available.

The saponins are glucosides of the type formula C32H54O18. Glucosides, incidentally, are chemical compounds which on hydrolysis yield an acid and a monosaccharide, mostly of the type glucose or maltose. The plant world is full of glucosides. Amygdalin is found in the bark of Prunus serotina. Salicin is found in certain species of Salix and Populus. The saponins are white powders, soluble in water, the solution foaming like soap when stirred or shaken. They are toxic and have antiseptic properties. Sasanqua saponin, C73H118O22 ' 3H20 from Camelia sasanqua is a typical one.

With the information our research had yielded, we found it would be necessary to know the botanical sources of these tannins and saponins. Knowing that I dabbled in botany and particularly dendrology, this assignment was given to me. Searching through the chemical texts and my own library on dendrology, it was not a difficult task to make a list of those species yielding commercial tannins and saponins. The following lists showing some of these commercial sources (by no means a complete list) are now offered:


TANNINS

1. Rhus copallina        (Anacardiaceae)        l. 17-38
2. Pistacia spp.             "                  g. 30-40
3. Schinopsis spp.           "                  e. 35-65
4. Aspidosperma spp.      (Apocynaceae)         l. 27-30
5. Alnus firma (minibari)  (Betulaceae)         f. 25-28
6. Terminalia chebula      (Combretaceae)       n. 30-40
7. Terminalia oliveri           "               b. 30-35
8. Larix europoea           (Pinaceae)          b. 9-10
9. Larix occidentalis           "               b. 10-12
10. Tsuga canadensis            "               b. 7-16
11. Castanea dentata         (Fagaceae)         b. 6-8
12. Quercus agrifolia           "               b. 19
13. Quercus aegilops            "      e.30-65; a. 17-40
14. Quercus cirris              "               g. 35
15. Quercus infectoria          "               g. 24-60
16. Quercus rubra               "               b. 25-30
17. Quercus tinctoria           "               b. 25-30
18. Quercus prinus              "               --------
19. Lithocarpus densifolia      "               --------
20. Acacia angica           (Leguminosae)       b. 20-25
21. Acacia binervata            "               b. 30
22. Acacia catechu              "               e. 60
23. Acacia decurrens            "               b. 20-61
24. Acacia microbotrya          "               b. 12-47
25. Acacia pycnantha            "               b. 40-50
26. Caesalpinia coriaria (Jacq.) Schl. -- Libidia coriaria:
      (Divi-divi; libi-libi) (Leguminosae)      p. 30-50
27. Pterocarpus spp. (Kino)     "               e. 40-60
28. Xylocarpus granatum      (Meliaceae)        b. 21-48
29. Eucalyptus spp.          (Myrtaceae)        --------
30. Rumex hymenosepalis      (Polygonaceae)     r. 25-30
31. Braguiera spp.          (Rhizophoraceae)    b. 22-52
32. Rhizophora spp.                "            b. 21-58
33. Nauclea gambir             (Rubiaceae)      --------

The small letters to the right mean: a - acorns; b - bark; e - extract; f - fruit; g - galls; l - leaves; n - nuts; p -pods; r - roots.

The numbers in the extreme right column refer to the percentage of tannins obtainable.

SAPONINS

A partial list of the commercial saponins is now offered showing the botanical sources;

1. Saponaria officinalis             (Caryophyllaceae)
2. Quillaja saponaria                (Rosaceae)
3. Mimusops globosa                  (Sapotaceae)
4. Bumelia retusa                    (Sapotaceae)
5. Sapindus spp.                     (Sapindaceae)

The above list is by no means complete, but it will serve to show the source of a few of the saponins. The Sapotaceae is the source of many of the commercial saponins. Incidentally, the drupe of Melia azedarach contains a saponin like body.

With our research now completed and our botanical nomenclature in order, we were able to make the patent application in which it was necessary to name the botanical sources of the commercial tannins and saponins. It was rather interesting to note the reactions of the various other chemists in the organization. Soon they were reeling off the terms Quercus, Terminalia, Schinopsis, etc., like old hands.

So, when my friends wonder why I find pleasure in collecting a few old sticks of wood, I can say I find it profitable in two ways, viz., the intense pleasure it affords me which cannot be measured in terms of the dollar, and finally, it came to my rescue when confronted with a difficult chemical research problem.

******************