February, 1927
ISDCSTRIdL, A S D ESGIA-EERISG CHE-IfIISTRY
number of 2 to 2.5. Poorer blacks give corresponding numbers of 14 to 17 and 3 to 3.5. The values for service chars show that new char is soon reduced to a shrinkage number of about 10 and a discard number of about 2 and that during service the softer, friable particles are discarded. There is suggested also the possibility of using the test to determine undue shrinkage as the result of faulty handling of the black during service. Conclusions The examination of new bone black begins with the identification of the types of bone that have been used in
225
its manufacture. Much information on this point can be obtained by a visual examination of the char particles, by the apparent specific gravity of a definite grist of the black, by the carbon and calcium carbonate content, and by color and ash adsorption tests. As color and ash adsorption are influenced by such factors as Brix, pH, concentration, and quality of color and ash, it is necessary to conduct color arid ash adsorption tests under carefully standardized conditions. A standard char should be included for reference and comparison. It is believed that the important property of socalled hardness is satisfactorily measured, for comparative purposes, by the test here described.
Electrolytic Conductivity of Solutions of Granulated Beet Sugars' By A. R. Nees THEGREATWESTERNSUGARCo., DENVER, COLO.
METHOD for determining the ash content and purity of granulated sugar by means of the electrolytic conductivity of the solution has been under development in this laboratory for nearly two years, and for the past year it has been employed as a routine test with yery satisfactory results. Ot,her workers2 have recently reported the use of this method for the determination of ash in ram sugars and certain refinery products. Apparently most of these investigators have used the apparatus and method of Toedt, which seem to give very satisfactory results. Not knowing of the existence of such an apparatus, the writer devised one to meet his own requirements, using standard equipment throughout so that it can be easily duplicated a t a reasonable cost.
A
Apparatus The apparatus is of the type which utilizes the current from a 110-volt', 60-cycle lighting circuit. It consists of a one-toone transformer, the purpose of which is to prevent injury to instruments through grounding of the circuit; an alternating current galvanometer; a dial-type Wheatstone bridge, and a conductivity celL3 The use of the galvanometer instead of the telephone receiver is a decided advantage. The dialtype Wheatstone bridge is much more conrenient than the usual slide n-ire and resist'ance box hook-up. While the apparatus of this type is not of the highest precision, it is rugged and dependable and will give a higher degree of accuracy than is ordinarily demanded in process control work. The manipulat'ion is simple and rapid; one man and a helper frequently make one hundrcd and fifty determinations in 8 hours. Determinations The determinations are carried out a t 25" C. using a solution containing 25 grams of sugar per 100 ml. The temperaPresented under t h e title "Electrolytic Conductivity of Solutions of Refined Sugar" as a p a r t of t h e Symposium on ' Refining of Sugars" before t h e Division of Sugar Chemistry a t t h e 72nd ,Meeting of t h e American Chemical Society, Philadelphia, P a . , September 5 t o 11, 1926. Zerban a n d Mull, Facts A b o u t Sugar, 21, 278 (1926); Toedt, Z . V e r . deut. Zuckeuind., 7 5 , 429 (1925); I n t e r n . Sugnv J . , 27, 503 (1925); Lunden, Z. V e r . d e u t . Z u c k e r i n d . , 7 5 , 763 (q.5); Inlern. Sugar J . , 27, 671 (1929). The alternating current aalvanometer is Leeds & NorthruD No. 2370-b; t h e Wheatstone bridge is L. & N.No. 4 i 6 0 ; t h e conductivity cell is L. & N. No. 4911.
ture control is quite important. For routine work where a large number of samples are to be tested, a thermostatically controlled water bath is necessary. If only occasional samples are being run, it is quite satisfactory to take about three readings between 24" and 26" C. and determine the reading a t 25 C. by graphic interpolation. It has been found convenient to express all results in terms and to transof specific conductance (as niultiples of late this figure into terms of ash and purity as occasion demands. The calculation is made according to the equation: O
C L = 11
where
L
= specific conductance
C
= =
R
conductivity cell constant resistance
A correction is made in the usual way for the conductance of the water. It is advisable to use freshly distilled water having a specific conductance of about 0.25 X reciprocal ohms, but especially prepared conductivity water is not necessary. The constant of the conductivity cell is determined by using a 0.001 S potassium chloride solution, the specific conducta t 25" C. The proper ance of which is taken as 14.72 X water correction is also made in this case. The relation between specific conductance and ash was determined by comparing the conductance figures Tvith the ash as determined in the usual way for a large number of samples of varying ash content. This relation was found t o be a straight-line function over the range ordinarily encountered in refined sugars. Later determinations of ash showed the established relation t o be reliable within the limits of accuracy of the direct method. The slope of the line was found to be such that tan e = 231.5 when specific conductance X 10-5 is plotted as ordinate and per cent ash as abscissa. Therefore the per cent ash may be determined by dividing the specific conductance X by 231.5. This value was determined for average beet sugars produced in Colorado, Sebraska, and Montana, and would undoubtedly be applicable to any beet sugar containing ash of similar composition. The ash-conductance relation for refined cane sugars has not been investigated. It is probably slightly different from that found for beet sugars because of relatively large percentage of highly ionizable alkali salts present in the ash of these sugars. The purity calculation is based on the fact that in beethouse products there exists a fairly constant and definite
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226
relation between the ash and total impurities. Once this relation is known the translation of per cent ash into terms of purity offers no difficulty. The calculation is, of course, not valid if there is an abnormally high adsorption of ash within the sugar crystal or a contamination of the sirups with ash from sources other than beets. Results
Some results showing the effect of sugar concentration on the-specific conductance are given in the accompanying table. Variation of Speci5c Conductance x 10-5 with Concentration SUGAR Pure A
B
CONCENTRATION, GRAMS PER 100 a.
5
0.025 2.2
. ..
10
15.0
20
25
35
50
0.035 0.039 0.039 0.037 0.021 .. . 3.9 5.2 6.1 6.6 6.7 6.4 14.0 18.3 21.5 22.9 23.7 19.1
The pure sugar was prepared by recrystallization from alcohol according to the modified method of Bates and Jack-
VOl. 19, No. 2
Sugar A is an ordinary grade of granulated beet sugar and B a very poor grade. It will be observed that the conductance is near the maximum a t a concentration of 25 grams per 100 ml. and that the variation of conductance with concentration is very slight. This fact influenced the choice of this concentration for regular use because extreme accuracy in weighing and dilution is obviously unnecessary. Practically all the writer’s efforts have been directed toward developing the method from the standpoint of its practical application t o the estimation of the ash content and purity of beet sugars. There remains to be determined, however, some very interesting fundamental data concerning the effect of sugar on the dissociation constant, and of other factors such as viscosity which influence the conductance of solutions of inorganic salts. Undoubtedly a study of these factors will lead to wider applications of the method in refinery and beet-house practice. Bur Standards, Circ. 44.
The Gelatinization of Lignocellulose’ 111-The Viscose Reaction By A. W. Schorger C. F. BURGESS LABORATORIES, MADISON,WIS.
ROSS, Bevan, and Beadle,2 who applied the thiocar-
C
bonate reaction t o thin beach shavings, stated that the resulting product showed none of the characteristic properties of viscose. Hancock and Dah13 found that the pithy stem of Aeschynomene aspera became gelatinous and 20 to 30 per cent went into solution. I n the case of elder The pith, less than 10 per cent was rendered ~ o l u b l e . ~ reaction has also been used to gelatinize wood.6 It is temerity to assert that lignin has yet been isolated from wood in a state even approximately unchanged. One of the hopes for the thiocarbonate reaction was the complete removal of the carbohydrates from wood. If successful, the residual lignin would a t least have been free from the effects produced by high temperatures and the use of strong acids. This end was not attained in one treatment. Such diEculties were encountered in filtration that the small quantities of material finally used precluded a repetition of the reaction on the residue. Experimental
SOLUTIOK-TOdetermine if raw wood would show some of the properties of viscose when subjected to the thiocarbonate reaction, 25 grams of white pine passing a 20-mesh sieve were added to a solution consisting of 25 grams of sodium hydroxide in 130 cc. of water and allowed to stand overnight. With thorough stirring, 20 cc. of carbon bisulfide were added, and after 3 hours sufficient water was added to give a volume of 500 cc. Most of the wood settled rapidly to a volume of about 300 cc. The vessel was allowed to stand several days to permit spontaneous coagulation. I n time the wood underwent syneresis. There was 1 Presented before the Division of Cellulose Chemistry at the 72nd Meeting of the American Chemical Society, Philadelphia, Pa., September 5 to 11, 1926. * J . Chcm. SOC.(London), 67, 444 (1895). 8
Chem. News, 72, 18 (1895).
Cross and Bevan, “Researches (lS95-1900),”p. 137. Lach, English Patent 12,324 (1912); “Portolac” Holzmasse Ges.. Austrian Patent 64,798(1914); de Cew. U. S. Patent 1,140.799 (1915). 4
6
an annular contraction of 6 mm. (0.25 inch) and the formation of a cylindrical gelatinous mass which now had a volume of 250 cc. Above the wood was a tender mass of jelly, which represented a portion of the wood that had gone into colloidal solution. DETERMINATION OF SOLUBILITY-All attempts to determine by filtration what amount of wood had been actually rendered water-soluble in the various experiments were unsuccessful owing to the gelatinous character of the material. Centrifuging (1200 r. p. m.) was finally employed. To determine the solubility of wood, one gram of the material passing a 100-mesh sieve was treated in a weighing bottle with 5 cc. of 18 per cent sodium hydroxide, allowed to stand overnight, 1 cc. of carbon bisulfide added, and allowed to stand 3 hours with frequent mixing. The mass was diluted with 20 cc. of water, transferred to a 50-cc. tube with 25 cc. of 5 per cent sodium hydroxide, and centrifuged. The supernatant liquid was carefully decanted, the sludge thoroughly mixed with 5 per cent sodium hydroxide solution, filling to the 50 cc. mark, and again centrifuged. In this way the sludge was washed four times with alkali and twice with water. The fourth washing with alkali showed only a faint opalescence when acidified. The sludge was then washed into a beaker, neutralized with hydrochloric acid, made up to 200 cc., 6 grams of sodium sulfite added, and heated to boiling to dissolve any sulfur present. The residue was filtered, washed with hot water, alcohol, and ether, and dried. All results are on the dry, ash-free basis. Under the above treatment the following solubilities were obtained: Aspen (Populus tremdoides) White pine (Pinus strobus)
Per cent 55.82 36.71
EFFECTOF GRINDING-since many of the reactions of cellulose are surface phenomena, numerous experiments were made using wood gelatinized by grinding in a ball mill in low and high concentrations of alkali. Beginning with ((wood flour,” obtained by dry grinding, there was a
