THE JOURNnL OF I.VD6GSTBlAL AND EVGINBEltIAT CHEMISTRY
Aug., 1022
nature and yirld of cellulose is tho recooked normal cooked sulfite pulp (232 Wlt) hlearlied witli 2 per cent hleacli. I.ICNIK-T~I~ term lignin is rather indefinite and is eommonly applied to that portion of wood which is not cellulose. In this paper lignin is defined as the residue insoluble in 73 per cent sulfuric acid under the ciinditions already outlined. The values given are not corrected Sor ash since tlie ash content for each series of samples is prnctically constant. A stronger concentration of acid is sometimes employed in t,his determination. However, we obt.ained higher values using 95 per cent sulfuric acid, as indicat,ed by the following fignres: SAMPLE KO. 2alWK
72 Per cent HISO. I'ei cent Mean 1.05
0.88
0.98
85 Per cent HlSOI Per criit Mean 1.66 1.65 1.85
The procedure in making the determinations with 95 prr cent sulfuric acid was to treat the sample for 5 min. with ten times its weight in cc. of acid. The reaction mixture was then dilut.ed t.o t,wenty tiines its volume and boiled under a reflux condenser for 4 hrs. The high values obtained are prohahly due to a certain amount of charring of the cellulose.'B Soft woods like spruce contain approximately 25 to 30 per cent lignin which, as shown by the data, is removed to a greater or less degree in the pulping pro , depending upon t,hc severity of cooking conditions and the nature of the process employed. The effect of bleaching in removing lignin from sulfite pulp is well indicated in each of the series of bleached samples, but particularly in the case of the raw-cooked sulfite samples (Series 221L). On the other hand, the inability of 1s
By C. A. Jacobson WSCT
v,ncini*
U N I V R R S m Y , MORDANTOWN, WBST VlXClNld
HE accompanying cut shows the construction of 8 buret siphon, especially suitable for use nith reagent bottles. The siphon is so constructed that a measured quantity of the liquid may be removed from the bottle with-
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omt nowine" or annlvine suction bv mouth. It is composed of& curet arm, calibrated in cubic centimeters from 0 to 25, and a heavy glass arm, G , which is supported in a bottle, K, by the stopper L. The upper end of A is drawn out to receive a rubber bulb, F, of a slightly larger capacity than the buret. The side tube D is provided wit.h a Tubber tube E and pinch clamp. The lower end of A is drawn out like the delivery end of a buret and provided with a stopcock, B. C is a glass plug whicli must be removed before withdrawing liquid from the bottle. To start the siphon, close l3, open E, compress the bulb F, clamp E, then release t,he pressure on F, and the bulb will draw the liquid through G i n t i A. If it is desired t.o withdraw a large quantit.y of t,he liquid from the hott,le, let the entire tube up to H, fill %,it11liquid. When I5 is opened the liquid siphons over. To stop the siphoning open E. If it is desired to nieihwre out a small quantity of the liquid, rcpeat t,he a.hove directions, but,, before the arm H fills with liquid, open E, and keep open while adjusting the height of t,he liquid in A, by means of the stopcock. ~
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bleaching to reinwe the lignin from alkaline cooked pulp is well illustrated in thr soda and sulfate samples. Bleaching appears to increa3e rather than decrease the amount of inaterial insoluble in sulfuric acid. The wll-conked siilfite pulps give valucs that. sgree well with tlrose for cotton, but t,he pulps obtaincd by alkdine cookiirg rim rather high in lignin, COPPER NuklB3:R--l'he copper nurnher was proposed by Schwalbc ihs a m e m s of measuring the degree of bleaching of cellulosic materials and a detailed mcthod of procedure was worked out in his laboratory for making the determin nt'ion. The simpler method employed in this investigation, as already outlined, gives comparable resnlts and is less tedious than the original method. Blank Tuns on Fchling solution gave an average value of 0.38, which was assumed to be constant. and the values were not corrected for it. The values obtained increase with increasing amount,s of bleach employed, but the unbleached samples also yield values of nearly the same magnitude as t,he mildly bleached pulps showing that products other than those produced in bleaching also reduce Fehling solution. BancroStz@concluded that the reducing action on Felrling sokdion is probably not characteristic of oxycellnlose, to wliicli it is iri part attributed, but to decomposition products of the cellulox!. The differences in the copper number with increased bleaching are not so pronounced as the corresponding differences in the alhli solubility. The latter constant appe.ars, therefore, to he more suitable as a mealis of determining the degree of bleaching than t,he copper number. The usual specification of a copper number not to exceed 1.0 would exclude all of the pulps except 231212.
2. p h w i o l . ChEm., [7]SS (1882). 913.
A Reagent-Bottle Siphon'
XReeemed Mag 16, 1922.
A,
731
'e.?.
Phys. Chcm.. 19 (1915), 159.
This reagent-lmtt,le siphon ean now be obtained in a 2-1. size; ot,lrer sizes eoukl doubtless be supplied also. The miter has used a similar siphon for several years and finds it very convenient. An addit.ional support, for the buret arm could be a.rranged without difficulty, but experience shows that A%.:-
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W"IIIII
be quite unnecessary. However, when t,he stopcock B is m a d e shorter than the glssscolJar, a rubber band passed around the lower end of the bottle and around the buret just above B would furnish ample support for the siphon.
