Sulfite extract

Although preliminary studies suggest that face-laminations can be obtained using adhesives made from condensed tannins that pass the standards of the American Institute of Timber Construction (< ), less is known about how to formulate adhesives using these materials for end-jointing of wood. This study, funded by the USDA Small Business Innovation Research Program, was undertaken to develop adhesive formulations containing 50% of sulfite extracts obtained from the bark of southern pine trees and demonstrate their use in... 

The sulfite extract of the pecan nut pith was obtained by extracting the finely ground red powder (509 gm) with sodium sulfite (20.4 gm) and sodium carbonate (2.0 gm) in 2549 mL of water. Approximately 1 hr was required to reach reflux temperature, and the suspension was heated at reflux for 2 hr. The suspension was cooled, the volume adjusted to a constant by addition of water, and it was filtered twice through glass wool. Aliquots (100 mL) of the recovered liquor were freeze-dried to determine the extract yield. The remainder was also freeze-dried to recover a dark brown solid. 

The sulfite extract performed nearly as well as the peanut skin tannin in bonding to nylon. Use of a tannin sulfonate derivative does not seem to hinder the development of strong bonds (compare peanut skin and sulfite extracts from pine bark). Likewise, the presence of carbohydrates in the tannin extracts does... 

Figure 2. Pullout forces of polyester cords for various tannin-containing adhesive dips as a function of percent resorcinol. 1, pecan pith sulfite extract 2, purified pine bark tannin 3, pine bark sulfite extract 4, peanut skin tannin.

Figure 4. Comparison of the pullout forces of polyester and nylon cords for dips containing pecan sulfite extract.

Table II. Elemental Composition and Carbohydrate Content of Sulfite Extracts from Pecan Nut Pith and Southern Pine Bark...

Condensed tannins are excellent clay dispersants. Sulfite extracts from conifer tree barks are very effective in reducing the viscosity and increasing the gel strength of muds used in well drilling (72, 92, 145, 246, 248). Condensed tannins still face strong competition from lignosulphonates for this application, particularly because of the comparatively low thermal stability and salt tolerance of the tannin (96). However, reaction of tannins with chromium increases their thermal stability considerably to permit their use in muds for wells drilled as deep as 6000 feet (208). Sulfonated condensed tannin derivatives have found use as dispersants in other specialty applications, such as ceramic clays, pigments, carbon black, and pesticides (93, 96). 

Sulfite Extraction Procedures for Flow Injection Analysis... 

A suspension of 3.90 g (19.6 mmol) of p-(bromomethyl)benzaldehyde (2.8) and 4.00 g (31.7 mmol) of sodium sulfite in 40 ml of water was refluxed for two hours, after which a clear solution was obtained. The reaction mixture was cooled on an ice bath resulting in precipitation of some sodium sulfite. After filtration, the solvent was evaporated. Ethanol was added to the remaining solid and the suspension was refluxed for 10 minutes. After filtering the hot solution, the filtrate was allowed to cool down slowly to -18 °C whereupon sodium (p-oxomethylphenyl)methylsulfonate (2.9) separated as colourless crystals. The extraction procedure was repeated two more times, affording 2.29 g (10.3 mmol, 53%) of the desired product. H-NMR (200 MH D2O) 5(ppm) =4.10 (s,2H) 7.44 (d,2H) 7,76 (d,2H) 9.75 (s,lH). 

After sulfuric acid work-up (accompanied by the formation of sodium sulfate), the resorcinol is extracted and isolated in a 94% yield based on y -benzenedisulfonic acid [98-48-6]. In addition to the technical complexity that goes along with the manipulation of soHds at high temperature, this process produces large amounts of salts (sulfite and sulfate salts) which economically as well as environmentally are not always desired. 

Xylose is obtained from sulfite Hquors, particularly from hardwoods, such as birch, by methanol extraction of concentrates or dried sulfite lyes, ultrafiltration (qv) and reverse osmosis (qv), ion exchange, ion exclusion, or combinations of these treatments (201). Hydrogenation of xylose is carried out in aqueous solution, usually at basic pH. The Raney nickel catalyst has a loading of 2% at 125°C and 3.5 MPa (515 psi) (202,203). 

Benzenedisulfonic acid [831-59-4] (disodium salt), produced by the neutralization of the disulfonic acid with sodium sulfite [7757-83-7] is used in the manufacture of resorcinol [108-46-3] (1,3-benzenediol) (2), a chemical component found in mbber products and wood adhesives (72). The disodium salt is fused with sodium hydroxide, dissolved in water, and acidified to produce resorcinol, which is isolated via extraction (73). 

Preparation from Waste Sulfite Liquors. The starting material for vanillin production can also be the lignin (qv) present in sulfite wastes from the ceUulose industry. The concentrated mother Hquors are treated with alkaH at elevated temperature and pressure in the presence of oxidants. The vanillin formed is separated from the by-products, particularly acetovanillone, 4-hydroxy-3-methoxyacetophenone, by extraction, distillation, and crystallization. 

Chromium Removal System. Chlorate manufacturers must remove chromium from the chlorate solution as a result of environmental regulations. During crystallization of sodium chlorate, essentially all of the sodium dichromate is recycled back to the electrolyzer. Alternatively, hexavalent chromium, Cr, can be reduced and coprecipitated in an agitated reactor using a choice of reducing agents, eg, sodium sulfide, sulfite, thiosulfate, hydrosulfite, hydrazine, etc. The product is chromium(III) oxide [1333-82-0] (98—106). Ion exchange and solvent extraction techniques have also... 

In a 4-I. wide-mouthed glass jar, fitted with a mechanical stirrer, is placed a solution of 150 g. (3 moles) of sodium cyanide (Note i) in 500 cc. of water and 318 g. (3 moles) of u.s.P. benz-aldehyde. The stirrer is started and 850 cc. of a saturated solution of sodium bisulfite (Note 2) is added to the mixture, slowly at first and then in a thm stream. The time of addition is ten to fifteen minutes. During the addition of the first half of this solution, 900 g. of cracked ice is added to the reaction mixture, a handful at a time. The layer of mandelonitrile which appears during the addition of the sulfite solution is separated from the water in a separatory funnel. The water is extracted once with about 150 cc. of benzene, the benzene is evaporated, and the residual mandelonitrile is added to the main portion. 

Pretreatment of the collected particulate matter may be required for chemical analysis. Pretreatment generally involves extraction of the particulate matter into a liquid. The solution may be further treated to transform the material into a form suitable for analysis. Trace metals may be determined by atomic absorption spectroscopy (AA), emission spectroscopy, polarogra-phy, and anodic stripping voltammetry. Analysis of anions is possible by colorimetric techniques and ion chromatography. Sulfate (S04 ), sulfite (SO-, ), nitrate (NO3 ), chloride Cl ), and fluoride (F ) may be determined by ion chromatography (15). 

A detailed procedure for the use of MCPBA recently appeared in Reagents for Organic Synthesis by Fieser and Fieser. The commercially available MCPBA (Aldrich) is 85% pure the contaminant, m-chlorobenzoic acid, can be removed by washing with a phosphate buffer of pH 7.5. The epoxidation is usually performed as follows a solution of 3 -acetoxy-5a-androst-16-ene (2.06 g, 6.53 mmoles) in 25 ml of chloroform (or methylene dichloride) is chilled to 0° in a flask fitted with a condenser and drierite tube and treated with a solution of commercial MCPBA (1.74 g, 20% excess) in 25 ml chloroform precooled to the same temperature. The mixture is stirred and allowed to warm to room temperature. After 23 hr (or until TLC shows reaction is complete) the solution is diluted with 100 ml chloroform and washed in sequence with 100 ml of 10% sodium sulfite or sodium iodide followed by sodium thiosulfate, 200 ml of 1 M sodium bicarbonate and 200 ml water. The chloroform extract is dried (MgS04) and evaporated in vacuo to a volume of ca. 10 ml. Addition of methanol (10 ml) followed by cooling of the mixture to —10° yields 0.8 gof 16a,17a-epoxide mp 109.5-110°. Additional product can be obtained by concentration of the mother liquor (total yield 80-90%). 

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