I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
SUI,: 1954
TABLE 111. ETHYLATION OF CELLULOSE
Ester, Moles per Hydroxyl
Constant. Concentration, 15.5N N a O H Cellulose, 5 4 ,grams (0.1 equivalent) Rate of stirring, 1700 r.p.m. Temp., Time, Avera e CzHsO Groups C. Hours % Cz&O per Glucose
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fonates with alkali cellulose diminishes as the length of the alkyl group increases. With a ratio of 3 moles of methyl p-toluenesulfonate per glucose hydroxyl and sufficient reaction time, a product could be obtained which contained 2.7 methoxyl groups per glucose unit. With a similar mole ratio, the ethyl ester brought about a substitution of 1.0 group per glucose unit, while the propyl ester gave only 0.4 group under similar conditions. Both the butyl and phenyl esters were found to be ineffective. LITERATURE C I T E D
Assoc. Offic. Agr. Chemists, “Official and Tentative Methods of
15 hours, a product was obtained which gave corrected values of 48.71% carbon and 6.81% hydrogen, corresponding to 0.44 and 0.30 C3H70 groups per glucose unit. An attempt a t butylation was made with a procedure identical with the above, except for the use of 4.4 moles of n-butyl p-toluenesulfonate per hydroxyl for 30 hours. Analysis of the product gave corrected values of 45.34% carbon and 5.93% hydrogen and indicated very little, if any, substitution. Cellulose was treated with phenyl p-toluenesulfonate under similar conditions, using 2 moles of the ester per cellulosic hydroxyl. The product had an analysis of 44.94% carbon and 6.15% hydrogen which indicated no substitution. DISCUSSION
The method of etherification of cellulose presented here is more efficient, is not appreciably exothermic, is, therefore, easier to control, and requires less care and attention than the usual laboratory preparation employing dimethyl sulfate. I t is apparent, however, that the reactivity of the p-toluenesul-
Analysis,” 6th ed., p. 762, 1945. Bates, F. J., and associates, Natl. Bur. Standards, Circ. C440, 510-11 (1942). Ferns, J., and Lapworth, -4., J . Chem. Soc., 101, 273 (1912). Finai, C., Ann. chim. applicata, 15, 41 (1925). Izmail’skiI, V. A+,and Razorenov, B. A., J . Russ. Phys.-Chem. Soc., 52,359 (1920). McLang, J., Chem. Trade J., 83, 143 (1928). Picton, N., U. S. Patent 2,067,946 (Jan. 19, 1937). Reeves, R. E., Barrett, B. J., and Mazzeno, L. W., Jr., J . Am. Chem. SOC.,74,4491 (1952). Reid, J. D., and Buras, E. AI., Jr., Science, 104, 326 (1946). Rodionov, V. M., and Vvedenskii, V. E., Bull. SOC. chim., 45, 121 (1929). Shirley, D. A., and Reedy, W. H., J . Am. Chem. Soc., 73, 4885 (1951). Slotta, K. H., and Franke, W., Ber., 63,678 (1930). Steele, R., and Pacsu, E., Textile Research J., 19, 771 (1949). RECEIVED for review December 18, 1953. ACCEPTED March 19, 1954. Presented before the Regional Conclave, AMERICAN CHEMICALSOCIETY, Xew Orleans, La., December 10 to 12, 1953. The Southern Regional Research Laboratory is one of the Laboratories of the Southern Utilization Research Branch, U. S. Department of Agriculture.
Preparation and Properties of Hydrocelldoses MERRILL A. NIILLETT, WAYNE E. MOORE, AND JEROME F. SAEMAN Forest Products Laboratory, Madison, Wis.
D
ILUTE acid hydrolysis has been a useful technique in providing information on the fine structure of cellulose. Most of the work t o date has been confined to the early phases of the hydrolysis ( 1 , 8, 11-15, $0)) in which only a minor portion of the starting material has been put into solution. In the study reported on in this paper, major attention was paid t o the hydrolysis of the resistant portion of cellulose, because, for chemical use, this portion governs the course of the reaction and comprises the greatest proportion of the final product. Native, .mercerized, and regenerated celluloses were hydrolyzed until as little as 10% of the original material remained undissolved. Reaction rates were determined and measurements were made of degree of polymerization and of moisture adsorption of the residues as functions of extent of hydrolysis. These measurements permit interesting and significant comparisons between the various celluloses. In the heterogeneous hydrolysis of cellulose, sugar decomposition occurs simultaneously, and in time the hydrocellulose produced becomes contaminated with humic materials. Various attempts have been made to take care of such contamination: by oxidation of t,he glucose as formed (16, 16), by a correction based on the kinetics of humic formation ( 1 7 ) , by selective solvent extraction ( l d ) , and by pressure percolation techniques (6, $0). In this paper an all-glass unit is described that makes use of constant-boiling hydrochloric acid a t atmospheric pressure both
as the hydrolyzing agent and as the thermostating agent. Samples are placed in sintered-glass crucibles through which the acid percolates, and hydrolysis can be continued until practically all the starting material is consumed with no noticeable formation of humic substances. Multiple setups permit a series of samples to be run a t the same time. EQUIPMENT
Figure 1 shows a diagrammatic view of the apparatus used for the preparation of hydrocellulose. The lower part of the extractor is made from the outer section of a size 50 standard-taper ground-glass joint. Fitted into the top of this joint is a Soxhlet condenser, which maintains liquidvapor equilibrium; no water is circulated through the jacket. Above the Soxhlet condenser is a water-cooled condenser. The sample is contained in a sintered-glass crucible of coarse porosity resting on glass beads. To facilitate uniform distribution of acid in the crucible and to eliminate splashing, a short length of glass rod is attached to the lower tip of the vapor-equilibrating condenser. Lubrication of the joint with silicone grease permits easy rotation of the unit, so that the refluxing liquid can be directed around the circumference of the filtering crucible. When the apparatus is in operation, constant-boiling hydrochloric acid distills from a 0.5- to 3-liter round-bottomed flask into the main part of the column and maintains the sample a t a constant temperature. The condensate, in equilibrium with the vapor, percolates through the sample, carrying hydrolysis
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roduct's with it. The siphon continuously discharges spent ydrolyzate to the drain. Tests in which the entire percolate and washings from five samples were collected and filtered through a fine-porosity crucible showed t,hat a ne ligible amount of material passed through the coarse crucibles turing a run. 31ATERIALS USED
,4 stock of constant-boiling hydrochloric acid (boiling point 108.54" C. at 760 mm.) was prepared by diluting concentratcd acid. The diluted acid was standardized against sodium hydroxide using constant-boiling hydrochloric acid as the primary standard ( 7 ) . The cellulosic materials hydrolyzed were: Ramie, commercial yarn. Linen, untileached commercial fabric. Cotton 1, bleached cheeseclotah meeting t,he requiremcnts of Federal Specification CCC-C-271A. Cotton 2, raw Empire fiber supplied by the Southern Regional Research Laboratory. Wood pulp 1, commercial hemlock sulfite pulp for acetylation. Wood pulp 2, experimental southern pine prehydrolysis sulfate pulp for nitration. Wood pulp 3, experimental southern pine sulfite . pulp- io1 vi
