Extract, Logwood

Dyestuffs, natural Ethyl acetate, natural Fustic wood extract Gambier extract Gum naval stores, processing but not gathering or warehousing Hardwood distillates Hemlock extract Logwood extract Mangrove extract Methanol, natural (wood alcohol) Methyl acetone Methyl alcohol, natural (wood alcohol)... 

Lo-Dex 10. See Maltodextrin Logwood extract. See Logwood (Haematoxylon campechianum) extract Logwood (Haematoxylon campechianum) extract... 

CAS 8005-33-2 EINECS/ELINCS 232-337-6 Synonyms Cl 75290 Haematoxylon campechianum Haematoxylon campechianum extract Logwood extract... 

Silk (qv) suture is made from the threads spun by the silkworm Bombjx mori. The fiber is composed principally of the protein fibroin and has a natural coating composed of sericin gum. The gum is usually removed before braiding the silk yams to make sutures in a range of sizes. Fine silk sutures may be made by simply twisting the gum-coated silk yams to produce the desired diameter. White silk is undyed. Silk is either dyed black with logwood extract or blue with D C Blue No. 9. The suture may be uncoated or coated either with high molecular weight polydimethylsiloxane or with wax. 

Nylon-6 [25038-54-4] (9) is made by the bulk addition polymerization of caprolactam. Monofilament Nylon-6 sutures are avadable undyed (clear), or in post-dyed black (with logwood extract), blue (ED C Blue No. 2), or green (D C Green No. 5). Monofilament nylon-6 sutures are sold under the trade names Ethilon and Monosof monofilament nylon-6,6 sutures, under the trade names Dermalon and Ophthalon and monofilament polyethylene terephthalate sutures, under the trade name Surgidac. 

Logwood extract—A reddish brown-to-black soHd material extracted from the heartwood of the leguminous tree Haemato>y/on campechianum. The active colorant substance is principally hematein. The latent coloring material is the unoxidized or leuco form of hematein called hematoxylin. The leuco form is oxidized by air. 

Heterocyclic colouring matters have been in use since prehistoric times through such natural products as indigo (1) (76MI11200), its 6,6 -dibromo derivative (Tyrian Purple), extracted from the shell of the Mediterranean mollusc, Murex brandaris (74MI11200), and logwood or haematin (2). Haematin is extracted in its leuco or colourless form, haematoxylin,... 

The precipitate (tannate of iron) is dissolved in dilute sulphuric add and the solution thus obtained extracted with ethyl acetate, the ethereal liquid being then separated from the aqueous solution and evaporated to dryness. The residue (tannic add) is dissolved in water and identified by means of dilute ferric sulphate or ferric alum solution (blackish-blue coloration). If the ink contains logwood, part of this passes with the tannin in such case, to identify the tannin in the aqueous solution of the ethyl acetate extract, distinctly alkaline ammoniacal copper sulphate is added, this giving a pretipitate in presence of tannin. 

Besides being subjected to the tests indicated for dyeing extracts in general, logwood extract is examined as follows. 

Qualitative Investigation.—The aqueous solution of logwood extract is deep red if the extract is neutral, reddish-violet if alkaline, or yellowish if acid (extracts containing tanning substances are always acid) it is turned reddish-yellow and yellow by acids and reddish-violet and then brown by alkalies. 

Detection of Molasses and Sugar.—These may be detected as indicated above for extracts in general (paragraph 5), but more particularly with logwood extract and more exactly as follows (Savini) ... 

Dyeing Test.—To ascertain the actual dyeing value of a logwood extract, the most important test is a dyeing test with wool mordanted with bichromate. 

The substance is treated with oxalic acid solution and filtered a red filtrate indicates the presence of logwood extract, which may be confirmed by the violet-blue precipitate formed by addition of alum and sodium carbonate. 

Red-wood and other dye-woods generally behave like logwood. Add alizarin reds are also extracted. 

A vatted black (indigo and logwood). e> Fibre blue or blue violet, solution crimson. Test for indigo by extraction, evaporation, and sublimation. 

Henna. Henna is the oldest and most widely used vegetable dye utilized in hair coloring. A temporary chestnut color is produced in blond or auburn hair by applying a paste of henna flowers and leaves ground in hot water immediately before use. (The dye is unstable in aqueous solution.) The addition of indigo achieves darker blue-black shades extracts of walnut shell or logwood enhance brown coloration. 

Hsematoxylin is prepared by extracting freshly rasped logwood with aqueous ether, evaporating, and mixing the residue with water [3]. The crystals which separate are recrystallised from water, preferably with addition of ammonium bisulphite to prevent oxidation. 

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