1 r,
13rtom IN I".n.rr
IY
Go.,
The Cooking Process I\, . Cooking Wood w i t h Sodirrrti 'J'kiiosulfatc, 8. 1. AHONOVbKY AND Ross AlKER (;ORTlll%ll Minnesota Agri'icultnral EhperimenL Station, St. Paul, Mirin Aspen sawdust h u s been cooked iuith sodiuni thiosulfaale, 46.8 and 93.6 per cent
[email protected] (based on the oi;en-dry wood), equiwderit on llie sodium bask lo 20 und 40 per cent sodium carboruile, respecti~!ely,for 2 arid 12 hours a1 170" un,d 186" C. The tolul organic matter, colatile orgunic aids (as acetic acid), lignin (72 per cent sulfuric ucid method), und pentosans in the residual liqrurrs niere higher, while lhe quantities of reducing sugurs obtained were lmoer than whpn water u m used as
I
S STIII1YISC the effects of tlre various constitiieiit. of t.lx conrmercial liquors on the cooking of wood it W R S sliown that m t c r (1j , aqueous solutions of sodium ORThoriate (2), and tliose of sodiiim sulfate (3j ham rather drastic effects 011 the wood coinpments. Using water as the sole cooking agent it was found that the pentosaw in the wood were iiearly completely destroyed; t,lie ligiiin (inwluble in 72 per cent solfuric acid) was iini:l~aiigcd in quantity bot reivlered part,ially solulile iii alcohol or glacial acetic acid, owing, probaldy to ilepolymerioat,i(iir; 37 per cent of the original Cross aird Bevan ccllulost: and 46 per cent. of the original alplla-cellulo soluiile in 17.5 per cent sodium liydroxiile. Sodium carbonate solutions did not have as dr on the pmtosans and Cross aid Bcrari ccllulose as did water alone, but they diarrged 54 per cent US the alpha-dulose and apparently emsed a portion of the li or made soluble iii 72 per cent sulfuric a I n contrast to cooking with smliiim carlioiiat.e, water ami aqueous solutions of sodium sulSatc or sodium bromiile bad approximately t.hc same effects oii the components of tlre vood, with one exceptiorr: TI& was tlie alplia-celluIor;e, of which 68 per cent was convcrt.ed into the varieties soluhle in 17.5 per cent sodium hydroside by sodium sulfate, arid 73 per cent hy sodium bromide.
the sole cooking ugeiil. TIE residuul uioods were darker, and partially to completely pulped. Snialler qrsantilies of lignin and sliglilly larger quantities (if pentosans were found in the sodium lhiosulfatepulps lhtiri in the residual iuoods of the corresponding water cooks. Sudium fhiosu[fak wus less destruclice uj" Cross und Betian cellulose but destroyed inore alpha-crllrdose Iliun did touter alone. Sodium lhiosulfute may be considered, under the conditions used in these investigations, ns a strong pulping agent. Sodiuiu tliiosiilfatc (hypo) was tlre chemical used in tlie iiivest.igat,iorrsrqxirtd ill this paper. It is a constit.uent of ell t,he commcrcial alkaline or neutral cooking liquors, such as Kraft or Keebra liquors, iuade u p of sulfur-containing salts. Eight cooks wcre run a t 170" or 186" C. for 2 or 12 110iirc. Crystalline Sa&Ol.5IT2O was used in quailtities equal to 46.8 aiid ! X I i per cent of the weight of oven-dry wood (100 p m i s airdry wood equal 91.0 grains ovendry) equivalent, , to 20 and 40 per cent sodium carbonate, wood i~sedwas aspen sawdust from tlre same Lmtcli describml in the preT4ous reports. The ratio of tlic volimie of liquor t,o the vcight of wood and the cooking Imctidurc were tlie same as in the other rcport,s. Some of the niethoils of itnalyris l i d to he niodified as will be sho~ve kiter. The results given arc tire mean of two or niorc detcrmiuati(ms. l ~ ~ ~ S 1 1 > Ula
