Pentosans pulps

O Dwyer22 finds that increased severity in the conditions of drying of English oak decreases the yield of hemicellulose extracted by 4% sodium hydroxide solution. Likewise, Meller23 notes that there occurs an increased amount of pentosan resistant to extraction with 7 % cold alkali whenever wood pulps are dried at high temperatures. Similar changes, associated principally with the furfural-yielding complexes, can be produced in both hard and soft woods.24... 

Finishing wood cellulose. The finishing process is made to obtain a higher a-cellulose content and to endow the wood pulp with a shape conducive to easy nitration. This is the last operation prior to nitration. It consists in removing hemicelluloses, pentosans, and hexosans, which are undesirable ingredients of wood pulp. An insufficiently purified wood pulp may contain 5-6% of pentosans, straw cellulose even as much as 20%, whereas cotton does not contain more than 0.5-0.6%. 

Naiman and Troitskii [9] have carried out extensive investigations to compare the nitration of cotton with that of cellulose differing in origin and purity from wood pulp, with hydrocellulose and oxycellulose, and with pentosans. The results are collected in Tables 90 and 91. 

Cellulosic raw materials. Linters or wood pulp cellulose are in use as raw material for manufacturing lacquer nitrocellulose. It is essential to use very well purified and bleached raw material. Wood cellulose should contain mainly a-cellulose. The admissible pentosan content is limited to traces only, because these compounds are a source of products insoluble in organic solvents. Cellophane can also be utilized for nitration. 

L.Brissaud, MSCE 33, 75-98(1947)(Detn of pentosanes in plant materials in pulp) 32) Collective, MSCE 33, 99-106(1947)(Refining of pulp from wood) 33)G.Petitpas, MSCE 34, 125... 

New International Dictionary, Merriam Co, Springfield, Mass(1951), 73 Alperox C. Trade name for tech lauroyl peroxide manufd by the Lucidol Division of Wallace Tieman, Inc, Buffalo, NY Alpha-Cellulose is that portion of cellulosic material(pulp, paper, etc) which,after treatment with 17.5% NaOH(mercerized strength) at 20° and diln to 7.3% NaOH,can be separated by filtration. The residue of alpha-cellulose is a good index of the undegraded cellulose content of the material. The alkali treatment removes degraded(oxidized or hydrolyzed) cellulose and short chain material. Some pentosans and hexosans may... 

Cationogen, the term, II, 42 Cattle food, from bagasse, IV, 296 molasses as, IV, 334 from sugar beet pulp, IV, 297 Cedar bark, Western Red, pentosan content of, V, 271 Cellobial, II, 67 hexaacetate, III, 195 —, 2-hydroxy-, heptaacetate, V, 16 Cellobiitol, 1,5-anhydro-, heptaacetate, V, 2, 27... 

Fermentation of Sulfite Waste Liquor. The sulfurous acid used in the sulfite pulping liquor causes hydrolysis of the more easily hydrolyzable components of wood, especially the pentosans in the hemicellulose. About 35 percent of the potentially fermentable sugars in the wood are hydrolyzed. However,... 

The researches have dealt with each phase of the pentosan determination. Many modifications have been introduced in the distillation procedure, in attempts to obtain ma.ximal yields of furfural. For e.xample, some workers prefer to distil with 23 % hydrobromic acid, rather than with the conventional 12% hydrochloric acid. Others distil in the presence of added sodium chloride, to avoid changes in acid concentration. Steam distillation has been used by a number of workers, who claim theoretical yields of furfural from pentoses, but Launer and Wilson found no advantage either in salts or in steam in the analysis of pulps and papers. Interfering substances are of two types materials other than pentosans which form furfural in the pentosan analysis, and substances which yield products which may be determined as furfural. TJronic acids and polyuronides yield furfural, although not quantitatively, and, in the case of materials containing appreciable quantities of these substances, it is usual to make a correction. The value of the correction to be applied has been determined experimentally by several workers, with somewhat differing results. 

Examples of the diminution of the pentosan of wood pulps by alkaline purification may be taken from the work of Richter. In a series of papers dealing chiefly with the pulping of hardwoods, Richter showed that either hot, dilute, sodium hydroxide or more concentrated sodium hydroxide at ordinary temperatures removes a substantial part of the pentosan from sulfite pulps. Some of Richter s data are shown in Table XVI. 

Removal of Pentosans from Unbleached, Sulfite Pulps ... 

Pulp NaOU added Ter., YieU, % Alpha cellulose, % Pentosan, %... 

Properties of Pentosans (SECTIONS 365, 382, 656).— (a) Tests for lignin.—Dissolve a few drops of aniline in a few drops of dilute hydrochloric acid, and dilute with 5 cc. of water. Pour one-half of the solution onto a piece of paper made from wood-pulp (newspaper) and one-half onto a paper made from linen. Repeat the tests using a solution of phloroglucinol in dilute hydrochloric acid. 

The higher pentosan content of ray cells as compared to that of the entire wood was noticed early, " as was also the fact that spruce pulp fines often contain more pentosans than does the unfractionatcid pulp. " An interesting study of the carbohydrate composition of parenchyma (ray) cells and prosenchyma cells in Scots pine, Norway spruce, and silver... 

In contrast to cotton cellulose, the pulp produced still contains a small percentage of low-molar-mass foreign polyoses, mostly pentosans. Further, some carbonyl and carboxyl groups always remain. The fibers are 1-3 mm long and so usually cannot be spun to textile fibers. Thus, sheet pulp is produced by sieving on long sieve trays and fibers are then produced by the viscose or cuprosilk processes whereby rayon is obtained. 

Some of the pentosans from wastes which accumulate in the processing of agricultural products are converted by acids to furfural, a raw material of increasing industrial value and interest. These and other waste hemi-celluloses such as those obtained from the pulping of wood represents a rich, almost untapped, source of raw material, much of which could be converted from a nuisance to a source of profit. (See also p. 799.)... 

Materials. TCF-bleached beech Mg-sulphite dissolving pulp (BS), with 93.8% R18,2.9% pentosan, and 1.7 copper number, and Eucalypt prehydrolysis kraft pulp (EK), with 96.6% R18, 3.6% pentosan and 0.2 copper number, were... 

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