USRE12069E - Alexander classen - Google Patents

Description

UNITED STATES PATENT OFFIC ALEXANDER CLASSEN, OF AACHEN, GERMANY.

PROCESS fi l GGNVQERTENG CELLULOSE INTO SUGAR.

$PEGIFIGATZON forming part of Reissued Letters Patent No. 12,069, dated December e0, 1902. Original Now 654518, dated July 2 1, 1900. Application forreissne flied December 5,1902. SerialNo. 134,048l

To (tZZ whom it may concern:

Be it known that I, ALEXANDER CLAssuN, a citizen of Germany, residing at Aachen in the Empire of Germany, have invented certain new and useful Improvements in Processes of Converting Cellulose into Sugar, of which the following is a full, clear, sud exact specification.

My invention relates to a, process by which the conversion of cellulose oi wood or the like duto sugar may be effected in fifteen minutes, workiugon 2. small or laboratory scale, at a temperature 05120" to 145 csutigrade by subjecting the materiel, preferably in a closed heated vessel, to the joint action of sulfurous acid and sulfuric acid. Working commercially or on a. larger scale the ti me required is longer and may be from, say, one hour up. The best temperature depends on the species of wood used The wood is preferably in the form of sawdust. Birch, for example, may be converted into sugar at about 130 centigrade and fir at about 145 oentigrade. Below this temperature the yield is smaller. The process may be conducted with a. previously made mixture oi sulfurous 'ucid and sulfuric acid containing two per cent. or more of sulfurous acid and about 0.2 per cent. of sulfuric acid dissolved in water or, what is decidedly (preferable, by starting with the sulfurous acid alone and causing the sulfuric acid to be formed in the unsceutstetef When the formation of sulfuric acid is thus caused to occur and preferably at the temperature which has been found to be best for the species of wood under treatment, a minimum.

yield of about three hundrcdgrams of sugar (tested by reduction of Fehlings solution) per kilo of dry wood or sawdust is obtained,

of which sugar eighty'per cent. (somhtimcs ninety per cent.) is fermeutable glucose, cor responding with about one hundred and twenty rams of absolute alcohol, which may be produced therefrom. Such glucose is taken into solution by weighing the substance so treated with water.

That by for the greater portion of yield of sugar is due to the joint action of sulfurous and sulfuric acid is proved by the fact that when the some species of material is treated under the same conditions with sulfurous acid alone, the air having been completely removed and being carefully excluded fiom the vessel, the yield of sugar is only half that obtained when both acids are used. As to the ferinentability of such sugar no examination has been made.

The formation of 'sulfuric'acid in the noscent state may be effected in either of two ways-first, by the action of atmospheric air or other gaseous mixture richin oxygen, and, second, by the action of oxidants capable of oxidizing sulfurous acid to sulfuric acid, such as peroxids, permanganutes, manganetes, and the like. The best yield is obtained when the formation of the sulfuric acid is efiected by introducing air ihany desired quantity, and that in or with the sawdust is commonly enough, or ot'her'gaseous mixture containing oxygen or introducing one of the aforesaid: oxidants either dissolved or suspended in water into the vessel as soon as the best temperature for conversion is reached and then blowing off after ten to fifteen minutes when working on a. laboratory scale or from, say, one hour upward wheh working on a. com mercial scale.

Estimetionsvof the sulfuric acid formed by the action of the air introduced show that the converted solution contains 0.2 to 0.5 per cent. of H 80 The advantages of the foregoing process are so prominent that they need not be emv phasizedn Apart from the great yield in formeutable prod uct,which is regularly obtained without any difiiculty, by far the greater part of sulfurous acid (which can be supplied at a. low price: from ore-roasting furnaces) can be recovered in order to be utilized again for the some on vother purposes by merely opening the valve at the arid of the operation and conducting the gas into water as it blows 01f. In addition to this the temperature is cousiderably lower and can be attained more easily than in Simonsens process, and the quantity of free acid in the solution which needs to be neutralized before fermentation is on the average smaller than in the usual processes; but facts of 'great importance are that the fermentation of the sugar by means of yeast proceeds in the some way as with commercial glucose under similar conditions of concentration and thatthe solution from the con- Q ['jie'rted sawdust-after being again-saturated ,vf1t h"sulfurous acid-cache utilized again for thelconver'sipn 'ofi rinore sawdust without. any

injuryto the-subsequent fermentation. In thisway it is ossible- .tio' produce a solution ontaining.- terj 1"per "cen't.;-of gsug'ar which is .suflicientlycoxicentrsted-for fermentation, so

641m: ,the'cjos'tjof concentration of thcj attenusol'u'tionf'ohtaiued.. by a single pperstion iii-avoided; In;this' waythe.'process difiers especially from all those hitherto known, as

itjisa known fact mat-me action of dilute sulfuric acid,- bothin'open and in closed 'ves sels, gives rise top'roducts which more or less hinder fermentation,

The great technicaiad antagealluded to, consisting in the repeated utilization of the sizirieliquid for the conversion of fresh materialghas not been obtained-hitherto by any jfuric acid in the foregoing description may be sustituted a mixture of sulfur-ans acid and hydrochloric acid, the latter containingv0.2 to

twoper cent. of acid, hyd rochlo'ric acid beingfor "this purpose equivalent to" sulfuric acid.

The process for converting cellulose into sugar which consists -in heatingthe cellulose in a closed vesselat a. temperature of 120 tov 145 centigrade with a solution containing sulfurous acid and sulfuric tially as described. ALEXANDER GLASSEN.

acid, substan- Wi t nesses;

HENRY OLoERn s, GOTIFRIED MEYER.