Insoluble residue, examination

To distinguish catechu from gambier, the substance is treated with 30% acetic acid or with 10% soda solution and the insoluble residue examined under the microscope if this consists of fragments of woody fibre the product is catechu, whereas if it is formed of parenchymatous cells and hairs with curved and dotted base, i.e., of leaf elements, the product is gambier. 

Detection of Glucose and Saccharose.—With colouring matters insoluble in water, these may be detected in the aqueous extract. Colours soluble in water and in alcohol may be treated in the cold with absolute alcohol (best mixed with a little ether) and the insoluble residue examined. 

In some cases the analysis can be shortened (ammonites, chlorUites). A weighed quantity is digested with acetone which readily dissolves nitro-compounds, nitroglycerine and hydrocarboiu. The insoluble residue is further tested as above, the salts being extracted with water, and the insoluble residue examined for wood meal, charcoal, alununium, sUicides and mineral matter. 

Preliminary structural studies of cutin and suberin breakdown involved examination of 13C NMR spectra for insoluble residues that were resistant to chemical depolymerization. In cutin samples, flexible CH2 moieties in particular were removed by such treatments, but CHOCOR crosslinks and polysaccharide impurities were retained preferentially. A concomitant narrowing of NMR spectral lines suggested that the treatments produced more homogeneous polyester structures in both cases. Our current studies of cu-ticular breakdown also employ selective depolymerization strategies with appropriate enzymes (1,28). 

Insoluble residues. Insoluble residue in the roots of peanuts accounted for 13.5X of the applied 48 hr after treatment with [ C]PCNB. This increased to 2lK after 33 days. The other plant systems examined also produced Insoluble residue after short-term treatment with [) C]PCNB (Figure 3). The values indicated for insoluble residues in systems other than peanut and peanut cell culture may be too high because these tissues were extracted with 70X acetone (IX) and acetone (2X) rather than with 80 l methanol (3X). 

Insoluble Matter.—20 grams of the substance are dissolved in at least 300 c.c. of water, the solution being filtered through a filter previously dried at 1050 and tared, and the insoluble residue thoroughly washed, dried at 105° and weighed. The residue is examined microscopically for starch. 

Extraneous Organic Substances.—To detect glycerine and dextrin, the substance is mixed with water, the insoluble matter allowed to settle, the liquid filtered, the filtrate evaporated and the residue examined as to its external characters, polarisation, behaviour when heated, etc. Starch is detected microscopically, and fatty oils by extracting the substance with ether and examining the ethereal extract. 

Detection of Starch.—The colouring matter is treated in the cold with water or alcohol, the insoluble residue being examined microscopically. 

Note 5. Insolubles are present when Klason lignin or wood meal is used. After a 40-min ozonation of wood meal, examination of the insoluble residue (in KBr) by FTIR showed the absence of characteristic lignin absorption bands. 

V.7 EXAMINATION OF THE INSOLUBLE RESIDUE It may well happen that after treating the sample with the various solvents, as described in Section V.6, some insoluble residue remains or the whole sample may prove to be insoluble. With this insoluble residue the preliminary tests, described in Section V.5, should be carried out these tests may supply valuable information as to the composition of the insoluble substance. In every case, the following methods of bringing the substance into solution for systematic analysis should be used. 

The metal or alloy does not dissolve completely analyse the filtrate as described in Section 5.7. Examine the insoluble residue according to Section... 

The effect of additives on the asphaltene from the Catalytic Incorporated (Cat. Inc.) coal liquid product was studied. Asphaltene is defined as the pentane insoluble but benzene soluble part of the coal liquid. The fractionation procedure has been described in detail elsewhere(l) and is shown schematically in Figure 1. Some work was also done with A240 petroleum pitch. Elemental analysis for the Wyoming sub-bituminous coal. Cat. Inc. coal liquid product, and Cat. Inc. asphaltene and A240 petroleum pitch are shown in Table I. Measured amounts of the additive compounds to be studied were added to the Cat. Inc. asphaltene and petroleum pitch. The samples were pyrolyzed and the pyrolysis residues examined by cross polarized light microscopy. Elemental analyses of the residues were done. 

Aj, = percent acid insoluble residue larger than 45 pm, other than quartz or flint. If a 20% acetic acid is used, dolomite also remains in the residue and thus can be examined. 

Larger filter sizes were used to retain degraded polymer with higher molecular weights and to examine the effect of the insoluble residues on filtration characteristics. 

This problem is encountered when testing materials used as pigments and in the examination of the so-called insoluble residue in qualitative inorganic analysis. An appropriate quick method of meeting this situation consists of fusing small quantities of the sample with sodium formate. If the temperature is maintained at about 240-250 (glycerol bath) only black elemental lead is formed in the colorless mass. The probable reaction is... 

For additives extracted from polyolefins, usually with diethyl ether, the extract is refluxed with ethanol and the solution is decanted from the insoluble residual polymer. On cooling, additives such as dilauryl and distearyl thiodipropionate separate out and are identified by infrmed examination. A 30 ul volume of the ethanolic solution is then spotted on to a thin Kieselgel 60 TLC plate and eluted with a suitable solvent, usually 98.5 + 1.5 toluene-ethyl acetate. The eluted plate is dried and sprayed with colour-developing reagents and the spots are examined. If the spots are to be submitted to mass spectrometric examination, methanolic iodine is used as the colour-developing reagent as this does not over-complicate the mass spectrometry. 

Torpex. Place 0.2 gram of the explosive in a five milliliter beaker and extract with three, 3 milliliter portions of acetone. Dry the insoluble residue and examine under a microscope. Note if the residue has the characteristic appearance of metallic aluminum. Place 0.2 gram of the explosive in a 5 milliliter beaker and digest with two, 3 milliliter portions of benzene, decanting the benzene into a small evaporating dish. Evaporate the benzene solution to dryness and test for TNT as indicated in table 13-1. Dry the insoluble residue from the benzene extraction and test for RDX as described in (1) above. 

Black powder. Place 0.2 gram of the black material in a 5 milliliter beaker, add 2 to 3 milliliters of distilled water, and stir for five minutes. Decant the liquid through a filter and catch the filtrate In a beaker. Evaporate this to dryness and subject the dried white solid to the tests shown in table 13-1. Dry the water-insoluble residue in the beaker, cool, and digest with two 5 milliliter portions of carbon disulfide, decanting these into an evaporating dish. Evaporate the carbon disulfide solution to dryness at room temperature. By means of a microscope, examine the yellow residue so obtained and the insoluble black residue from the carbon disulfide extraction. Note if they have the characteristic appearances of sulfur crystals and charcoal, respectively. 

Konig and Waldorf discuss analysis of hair and body shampoos (32). The shampoo is first evaporated to dryness and extracted with isopropanol or 95% ethanol to separate the surfactant, which is qualitatively identified by IR. The alcohol-insoluble residue is also examined by IR in case a less-soluble surfactant remains there. The alcohol extract is then separated into anionic, cationic, nonionic, and amphoteric surfactant fractions by ion exchange. Anionics can be separated into sulfonates and carboxylates by use of strongly basic anion exchange resins in the Cl" and OH" form, respectively. Anionics are further characterized by TLC. Nonionics are likewise characterized by TLC. Once the components are identified, quantitative analysis is by the usual methods, described elsewhere in this volume. 

Reduction of a nitro compound to a primary amine. In a 50 ml. round-bottomed or conical flask fitted with a reflux condenser, place 1 g. of the nitro compound and 2 g. of granulated tin. Measure out 10 ml. of concentrated hydrochloric acid and add it in three equal portions to the mixtiue shake thoroughly after each addition. When the vigorous reaction subsides, heat under reflux on a water bath until the nitro compound has completely reacted (20-30 minutes). Shake the reaction mixture from time to time if the nitro compound appears to be very insoluble, add 5 ml. of alcohol. Cool the reaction mixture, and add 20-40 per cent, sodium hydroxide solution imtil the precipitate of tin hydroxide dissolves. Extract the resulting amine from the cooled solution with ether, and remove the ether by distillation. Examine the residue with regard to its solubility in 5 per cent, hydrochloric acid and its reaction with acetyl chloride or benzene-sulphonyl chloride. 

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