June, 1920
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
pure (free from unsaponifiable matter) f a t t y acids, which is given below, as t h e result both of calculation and experiment.
+
Impure fatty anhydrides unsaponifiable matter (100.00 7.33). = Calculated combining wt. of impure fatty anhydrides., Calculated combining wt. of impure fatty acids (274.17 f 9 . 0 1 ) . . ......................................... = 1.16).. = Pure fatty anhydrides (92.67 Calculated combining wt. of pure fatty anhydrides.. = Calculated mean combining wt. of pure fatty acids (270.73 9.01) =
-
-
.................................
+
............... ... ..................................
..
-
92.67 per cent 274.17 283.18 91.51 per cent 270.73 279.74
Five grams of t h e recovered pure f a t t y acids (39.708 g.) were saponified by boiling with excess of alcoholic potash and their combining weight determined. The actually determined mean combining weight found was 279.3, agreeing closely with t h e calculated value. IODINE ABSORPTIONWijis Method-The lower values in t h e case of t h e f a t t y acids shown below are due t o t h e fact t h a t they .did not contain t h e unsaponifiable matter, which itself would have absorbed iodine, and also probably t o some oxidation of t h e acid. Iodine number of original oil Iodine number of the pure f a
................
SUMMARY Total pure fatty acids in sample soy-bean oil Unsaponifiable matter (+ possibly some free
TOTAL ...............................
Glycerol. ............................ Combining weight of ordinary fatty acids Combining weight of pure fatty acids.. . .
138.45 and 137.39 132.83 94.966 per cent 96.126,per cent 283.18 per cent
THE PROXIMATE COMPOSITIONS OF KOREAN HEMP AND RAMIE By Yoshisuke Uyeda LABORATORY O F AGRICULTURAL CHEMISTRY, UNIVERSITY OF CALIPORNIA ADRICULTURAL EXPERIMENT STATION,BERXELEY,CAI,. Received December 31. 1919 INTRODUCTION
This paper is the first of a series of reports on Korean bast fibers from t h e standpoint of textile chemical research. Hemp and ramie have long been t h e most important raw textile materials in Korea. The former, grown throughout t h e country, is much larger in output t h a n t h e latter and its bast fiber is obtained by an artificial retting process combined with scutching, and a spinning operation performable only b y skilled hand labor. The latter, which is t h e chief textile fiber of China and known as China grass, is limited in locality and has a smaller output, b u t its quality is excellent and textiles made from i t are highly valued as summer cloth in Korea. The treatment of t h e ramie fiber is a kind of “dew retting,” a treatment commonly applied t o all bast fibers, followed by t h e same scutching and spinning operations as are used upon the hemp fiber. I n t h e course of experiments on bleaching t h e Korean hemp and ramie weaves which were made at t h e Central Experiment Station, General Government of Korea, by t h e present author, several difficulties were found. For example, t h e whiteness was not entirely satisfactory, t h e loss of weight after bleaching was considerable, and t h e strength of t h e weaves was much weakened b y t h e treatment. I n order t o overcoine these troubles, i t is necessary t o have ample knowledge of t h e chemical composition of the fibers
573
and their behavior toward various reagents. Another important reason which led t o t h e present research is t h e fact t h a t t h e chemistry of t h e pectocelluloses, among which hemp and ramie are classified, is still obscure and offers many problems for investigation. The first step, therefore, is t h e consideration of t h e proximate composition of these fibers. Generally speaking, we have very little knowledge of t h e cheyical constitution or even t h e proximate composition of t h e I( compound’’ celluloses, not only pectocellulose, b u t also ligno- and adipocellulose. Methods of procedure for satisfactory analysis of compound celluloses are practically absent from t h e literature. Muller’ gave analytical results on hemp and ramie. He determined hygroscopic moisture, ash, water extract, fat and wax, and cellulose, estimated t h e residue by difference, and reported i t as “incrusting and intercellular substances and pectic constituents.” The present author2 also reported analytical results for t h e Korean products, following Muller’s .scheme. Cross and Bevan3 consider t h e question of “incrusting” morphological rather t h a n chemical. As a starting point for further investigation i t is very desirable t o consider more accurate and complete proximate analytical methods. W. H . Dore4 of this Station recently proposed a scheme for t h e proximate analysis of wood and applied it to t h e proximate analysis of certain California woods. I t seemed possible t h a t this proposed scheme of analysis might be quite applicable t o t h e pectocellulose which was t h e subject of the present work. As f a r as our present knowledge extends, i t appears t h a t the structural substances common t o hemp a n d ramie consist chiefly of pectocellulose, together with lignin and substances extractable by organic solvents. According t o Cross and Bevan,6 pectocellulose is a substance which is decomposed b y boiling with dilute alkali into insoluble cellulose and soluble non-cellulose derivatives (pectin, pectic acid, and metapectic acid). The material extracted b y organic solvents consists chiefly of a fatty and waxy substance together with other substances of less frequent occurrence. T h e presence of lignin in both Korean hemp and ramie was noted by t h e author6 in the previous paper. The proximate compositions of t h e fiber are included in this paper, together with a discussion of t h e methods of analysis and t h e results obtained. EXPERIMENTAL
The samples which were used in this work were representative samples of Korean hemp and ramie of superior quality. ( I ) Hemp (Canlzabis sativa), retted and scutched. A single fiber has an average length of 1.2 t o 1 . 3 meters and a breadth of 0.6 t o 0 . 7 mm. I t has a pale brown color. ( 2 ) Ramie (Boeheria nivea), retted and scutched. A single fiber has an average length of 0 . 7 t o 1.1 meters Mathews, “Textile Fibers,” 1904, 191, 197. Chem. I n d . Japa-n, 21 (1918), 314; Chem. Abs., 1%(1918), 2127 J . Chem. Ind. J a p a n , 2 1 (1918), 1043; Chem. Abs., 13 . (1919), 794. a “Cellulose,” 2nd Ed., p 214. I 4 THIS JOURNAL, 11 (19159, 556. 5 “Cellulose,” 2nd E d , p 217. 0 L O C . cit. 1
* J.
5 74
VOI. 12, NO.6
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
a n d a breadth of ' 0 . 2 t o 0.6 mm. The color is pale yellow. Both samples were prepared for analysis by cutting with sharp scissors into small pieces of a n average length of one centimeter. Mason fruit jars were found t o be convenient for keeping t h e moisture content constant throughout t h e experiments. LIFTHODS O F ANALYSIs-The analysis included t h e determination of loss on drying, extractives soluble i n benzene, extractives soluble in alcohol, substances soluble i n water, substances soluble in one per cent sodium hydroxide, cellulose, and lignin. The following methods of procedure were modified from those originally proposed by Dore for t h e analysis of wood. Loss on Drying-Two-gram samples are p u t i n a weighing tube, dried in a constant temperature electric oven at 100' C. for 16 hrs. (over night), and weighed. Benzene Extract-The fibers, dried as above, are placed i n a n alundum thimble and extracted with I O O cc. of t h e solvent for 6 hrs. in a Soxhlet apparatus on a hot plate. After t h e solvent is evaporated t h e residual extract is dried for one hour at 100' C. and weighed. Alcohol Extract-The extracted fibers are next subjected t o extraction with g j per cent alcohol, using exactly t h e same process as i n t h e benzene extraction. Water Extract-After extraction with benzene and alcohol, t h e above sample is dried a t 70' t o 80' C. t o expel t h e adhering solvent, then digested with 100 cc. .of distilled water i n a zjo-cc. Erlenmeyer flask fitted with a reflux condenser. After heating on a hot plate for 3 hrs., t h e sample is filtered, washed with hot water, dried for 16 hrs. a t 100" C., and weighed. For filt r a t i o n a Gooch crucible, with a mercerized cotton .disc fitted in t h e bottom as proposed b y Dore, is used. T h e weighing of t h e crucible, both before and after t h e filtration, is carried out in a glass-stoppered weighing bottle. The water-soluble material is calculated by adding loss on drying, benzene and alcohol extracts, and residue after water extraction, and subtracting this s u m from t h e total weight taken. Solzcble in One Per Cent Sodium Hydroxide S o h tioiz-The dried residue after water extraction is transferred t o a 2 j 0 cc. Erlenmeyer flask, I O O cc. of one per cent sodium hydroxide solution are added, and a reflux condenser fitted t o t h e flask. It is then heated o n t h e hot plate for one hour, filtered off on t h e same Gooch crucible, washed well with hot water, dilute acetic acid, and finally with hot water again, dried i n t h e weighing bottle for 16 hrs. a t 100' C., and weighed. The loss in weight of crucible and contents represents substances soluble i n one per cent sodium hydroxide solution. Cellulose-The dried residue from t h e alkali treatment is washed with water and t h e excess of water drawn off b y suction. T h e crucible is placed on a filtering flask attached t o a suction pump, and covered with a tightly fitting glass cap which is connected t o a chlorine generator. A moderately rapid stream of washed chlorine gas is passed through t h e crucible for 2 0 min. with t h e help of suction, t h e passage of t h e g a s
being judged by t h e rate of passage of bubbles through a wash bottle containing water and attached to t h e chlorine generator. T h e crucible is removed and placed on another suction flask, and dilute sulfurous acid is immediately poured on t h e material, after which i t is washed with water. T h e crucible and its cont e n t s are then placed i n a jo-cc. beaker, sufficient 3 per cent sodium sulfite solution added, and t h e whole heated on t h e steam bath for three-quarters of an hour. T h e crucible is removed from t h e solution and placed on t h e suction flask, and t h e sulfite solution, together with t h e material which has floated into t h e beaker during t h e operation, is poured into t h e crucible, after which t h e contents are well washed with water. T h e chlorination and sulfite treatments are repeated 3 times, t h e periods of chlorination being 15, I j, and I O min. After t h e last treatment with sodium sulfite solution, t h e material is thoroughly washed with hot water, placed in t h e glass-stoppered weighing bottle, dried a t 100' C. for 16 hrs., a n d weighed. Lignin-Another 2-g. sample is dried and extracted with benzene and alcohol i n t h e manner described above, and, after t h e adhering solvent has been expelled by heating t o 70' t o 80" C., t h e fibers are transferred t o a large Erlenmeyer flask and treated with 2 0 g. of 7 2 per cent sulfuric acid. T h e flask is rotated and shaken t o moisten t h e material with acid, and allowed t o s t a n d a t room temperature with occasional attention t o see t h a t all t h e material comes i n contact with t h e acid. At.the end of 3 hrs., 500 cc. of distilled water are added and t h e mixture i s heated for 2 hrs. on t h e hot plate under a reflux condenser. The residue is filtered b y suction on a t a r e d Gooch crucible similar t o t h a t used in other determinations, washed well with hot water, dried in a weighing bottle for 16 hrs. a t 100" C., and weighed. A N A L Y T I C A L DATA-The following results were obtained for Korean hemp and ramie: TABLE I-PROXIMATE SAMPLE
C O M P O S I T I O N S O F KOREAN HEMPAND RAMIE (Results in Percentages) HBMP RAMIE
........................
Loss on drying., Benzene extract Alcohol extract. ...... Water-soluble . . . . . . . .
8.83
1.92 1.20
e...
TOTAL .............................
4.50 18.53 62.42 3.32
10.50 0.86 0.75 3.79 17.27 65.88 0.66
--
-
100.72
99.71
D I S C US S I O N
A critical discussion of t h e methods of analysis proposed by Dorel is presented in his paper. A brief discussion of t h e methods of analysis and results obtained is included here i n order t o consider t h e application of Dore's scheme t o t h e analysis of bast fibers, and t o s t u d y for t h e purpose of future work t h e proximate composition of t h e fibers from t h e standpoint of textile chemistry. LOSS O N DRYING-The methods of drying cellulose material have been studied by a number of investigators. They should be'considered, not only in regard t o t h e two essential factors (temperature and duration of drying), b u t also from t h e standpoint of convenience as well as accuracy. Drying a t ~ o j 't o 107' C. . t o 1
LOC.cit.
June, 1920
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
remove all hygroscopic moisture was accepted by Schwalbe, Renker, and Konig and Huhn, and this method has been considered t h e standard method of drying. As t o t h e duration of drying, Schorgerl affirmed t h a t , in t h e case of wood sawdust, t h e moisture content, could be determined with sufficient accuracy by drying for 7 hrs. a t 105’ t o 107’ C. There is, however, no definite line of demarcation between hygroscopic moisture and water expelled due t o t h e dehydration of cellulose itself. T h e term “absolutely dry” is therefore more or less conventional. T h e experiments by Schorger2 on t h e effects of prolonged heating upon t h e weight of wood are t o be taken as one of t h e proofs of t h e above statement. T h e method of drying practiced here and also b y Dore may not be regarded as a n accurate moisture determination, b u t as a n arbitrary treatment. I t is, nevertheless, t o be regarded as t h e most logical, from t h e standpoint of convenience, for t h e proximate analysis of cellulose materials. Since t h e dryings a t separate stages in t h e analysis are made i n t h e same manner as in t h e determination of loss on drying, t h e results are strictly comparable. I n view of t h e above considerations t h e results are expressed as “loss on drying” and not as “hygroscopic moisture.” Experiments were made on t h e time effect i n determining loss on drying. Two grams of t h e fibers were p u t in a weighing tube, dried for 16 hrs. i n a n electric oven a t 100’ C., and weighed. They were then dried again for 16 hrs., and weighed. There was practically no difference between t h e first and second dryings. Loss SAMPLE H e m p . . ..................... Ramie.. ....................
ON DRYING(Per cent) 16 Hrs. 32 Hrs. 8.81 8.86 10.50 10.58
B E K Z E N E A N D A L C O H O L EXTRACTS-The amOUntS Of extractives removed from hemp fiber by these solvents are considerable. The benzene extracts in both hemp and ramie are composed of brown waxy substances which redissolve readily i n benzene. The alcohol extracts of t h e fibers give a light green solution, probably due t o chlorophyl. They are obtained as brownish green pasty residues, p a r t of which is insoluble in alcohol even in t h e boiling state. T h e substances soluble in these solvents, termed “oil-wax complex” by Cross and Bevan, are t h e constituents of the cuticular tissues of t h e fibers. T h e oil-wax complex in t h e bast fibers bears a n important relation t o t h e bleaching process for these materials, since one of t h e chief difficulties experienced i n hemp and ramie bleaching consists in breaking down these impurities without injuring t h e bast fiber p r ~ p e r . ~ T h e analytical results show t h a t hemp contains more of these impurities t h a n ramie, and this fact suggests, as is actually t h e case, t h a t t h e former is more difficult t o bleach t h a n t h e latter. S O L I J B L E I N W A T E R A X D D I L U T E ALKALI-PeCtOCellulose contains much material which is easily rendered soluble b y hydrolyzing agents, especially by alkali. T h e determinations of material soluble i n water and THISJOURNAL, 9 (1917), 561. L O C . cat. a Cross and Bevan, “Cellulose,” p. 80.
575
alkali under t h e prescribed conditions not only give t h e proximate compositions .of t h e fibers, b u t also suggest their chemical behavior when these textile fabrics are subjected t o treatment such as t h e scouring operation i n t h e bleaching process. T h e determinations of “soluble in alkali” have hitherto been made i n a n open beaker, keeping t h e concentration of alkali constant. T h e use of t h e Erlenmeyer flask with a reflux condenser, as given in t h e present method of procedure, may be regarded as more logical as well as more convenient. I n both hemp and ramie t h e substances soluble i n alkali are considerable, and t h e main p a r t is considered t o be pectin substance. This is t h e characteristic constituent of t h e so-called “noncellulose” of t h e pectocellulose, and is easily rendered soluble b y t h e action of alkali. Our knowledge of t h e chemistry of pectin substance is mostly due t o t h e original researches of Fremy and Chondnew, a n d t h e r e is need of much further investigation. cELLvLosE-Various methods have been proposed for t h e determination of cellulose. Renkerl compared these methods for various cellulose. materials a n d concluded t h a t of all t h e methods investigated, none was so satisfactory as Cross and Bevan’s method of chlorination. For t h e chlorination, t h e method proposed b y Sieber and which has also been used b y Johnsen and H ~ v e ywas , ~ suggested by Dore as most convenient. This method was used throughout t h e present work and its reliability confirmed. By t h e treatments with water and alkali preceding t h e chlorination, t h e greater p a r t of t h e substances less resistant toward hydrolyzing agents is removed. T h e residue therefore probably consists of t h e most resistant cellulose, termed “ortho-cellulose” b y Konig and R u m p and “normal cellulose” by Cross and Bevan, together with a small quantity of lignified tissues. The loss i n weight b y chlorination after t h e alkali treatment is very small, as is shown in Table 11. TABLE11-Loss IN WEIGHTBY CHLORINATION (Percentage on Air-Dry Basis) HEMP RAMIE SAMPLE (1’) (2) (,1 ,) (2) ~., , , , , 67.48 67.81 Residue after alkali treatment. . . . . . . . 65.11 6 4 . 9 3 65.70 6 6 . 0 6 Residue after chlorination (cellulose). 6 2 . 4 2 6 2 . 4 3 1.78 1.75 2.50 Loss in chlorination.. . . . . . . . . . . . . . . . 2 . 6 9 ~~~
.
I n t h e course of t h e chlorination t h e sulfite solution becomes very brown. The main Substance broken up b y this treatment may therefore be regarded a s lignified tissue. After chlorination t h e residues are pure white and readily and completely soluble in 7 2 per cent sulfuric.acid, and their amounts are accordingly tabulated as t h e cellulose content of t h e fibers. T h a t t h e alkali treatment before chlorination has a n important effect on t h e yield of cellulose is shown b y Table 111. OF ALKALI TREATMENT ON THE YIELDOF CELLULOSE (Percentages on Air-Dry Basis) CELLULOSE PRELIXINARY TREATXENT HEMP RAMIE 76.69 Benzene and alcohol extraction alkali treatment omitted 71 . 4 9 After benzene and alcohol extra’ction, digested for 30 min. with one per cent N a O H . . ........................ 65.99 68.35 After benzene and alcohol extraction digested for one hr. with one per cent Pu’aOH.. ........................ 62.42 65.88
TABLE111-EFFECT
1
1
2
2 8
Cross and Bevan, “Researches on Cellulose,” 3, 30. Chem. A b s . , 8 (1914), 1202. P a p e r , 2 1 (1918), 40.
T H E J O V R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
5 76
The cellulose residues obtained by various alkali treatments differ apparently in their physical nature, a n d further chemical investigation is necessary. Such researches will be made shortly by t h e author. LIGNIN-Konigl treated t h e extracted lignified materials with 7 2 per cent sulfuric acid according t o t h e method of Ost and Wilkening,z and regarded t h e noncellulose residue as lignin. This method was recently applied by Dore for the determination of lignin in wood. The d a t a for lignin in hemp and ramie given i n this paper were obtained b y Konig's method. b The lignin, which is believed b y investigators t o exist in combination with cellulose as lignocellulose, may not be a constituent of t h e bast fibers belonging t h e pectocellulose proper. The cuticular tissue of fibers in t h e stem, which is much lignified, occurs in intimate contact with t h e bast fiber and part of i t remains after t h e scutching operation. It appears t o t h e author t h a t t h e determination of lignin in hemp a n d ramie serves as one of the indications of t h e completeness of the whole retting process. The lignin is partly attacked b y alkali digestion, and experiments were made on t h e effects of such digestion upon t h e yield of lignin. Two grams of t h e fibers were dried, extracted with benzene, alcohol, water, and one per cent sodium hydroxide as in t h e cellulose determination., and t h e lignin determination was made upon t h e dried residue as before. The results are given in Table IV. TABLE IV-EFFECT
OF
ALKALIDIGESTION O N THE YIELD OF LIGNIN HEMP RAMIE
Loss on drying.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Benzene extract., . . , . , , , , . , , , , , , , . , , . . , , , , , .
,
8.83 1.92
. . . . . . . . . . 1.20 . . . . . . . . . . 4.50 e . . . . . . . . . . 18.53 Cellulose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.42 Lignin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.99 TOTAL. .......
......
--
99.39
10.50 0.86
0.75
3.79 17.27 65.88 0.18
-_
99.23
SUMMARY
I-The proximate compositions of Korean hemp and ramie are given, as determined by modifications of t h e analytical method proposed by Dore. 2-The analytical results are discussed from t h e textile chemistry standpoint for the benefit of future investigations. 3-The presence of lignin in both hemp and ramie is confirmed quantitatively. My sincere thanks are given t o Mr. W. H. Dore for his kind suggestions and encouragement. SHORT COMMERCIAL ANALYTICAL METHODS FOR THE DETERMINATION OF PURITY OF IMPORTANT CHEMICALS USED IN PYROTECHNICS By Henry B. Faber and William B. Stoddard NEWYORE,N. Y. Received January 29, 1920 1-DETERMINATIOS
OF
SMALL
AMOUNTS
OF
I n potassium nitrate t o be used in t h e manufacture of military pyrotechnics, t h e presence of salts of sodium is t o be avoided for two reasons: 2
Chem.-Zlg., 36 (1912), 1101. I b i d . , 34 (1910), 461.
12,
No. 6
I-On account of t h e flame color imparted b y small amounts of sodium compounds. 2-On account of t h e hygroscopicity of sodium nitrate, which might cause the finished articles t o absorb moisture t o such a n extent as t o irtterfere with their proper functioning. The problem, therefore, became one of determining sodium nitrate in quantities as low as 0.01 per cent in potassium nitrate. Reference t o t h e literature indicated t h a t t h e method of Walter Craven Ball' was t h e only one available. This method is based upon t h e fact t h a t when a solution of potassium nitrate, bismuth nitrate, a n d cesium nitrate, acidified with dilute nitric acid, is added t o solutions of sodium nitrate, even in t h e presence of large quantities of potassium salts, t h e sodium is quantitatively precipitated as cesium sodium bismuth nitrite, having t h e formula 5 Bi ( N02)3.gCsN02.6NaN02. The precipitate is obtained in t h e form of large yellow crystals which are very easy t o handle. It was found convenient t o modify t h e method used b y Ball, who made t h e precipitation in a separatory funnel, t h e upper part of which was kept filled with coal gas. After t h e precipitate had entirely separated, i t was removed b y poking t h e crystals down through t h e stopper of the funnel. The present writer has found t h a t a series of 3 0 cc. Erlenmeyer flasks can be used for making a number of determinations a t t h e same time. One gram of each sample of potassium nitrate t o be analyzed is dissolved in 5 cc. or less of water and placed in a flask. One cc. of 2 N nitric acid is then added and, by means of a pipette, I O cc. of t h e reagent. The flasks are shaken and connected, and coal gas is passed through t h e series until t h e air has been replaced. The rubber t u b e a t one end of t h e series is then closed b y a glass plug, and t h e other end b y a Bunsen valve, which is used in order t o permit t h e escape of nitrous fumes which are developed in small amount. T h e cesium sodium bismuth nitrite begins t o separate within a few minutes and collects on t h e bottom of t h e flasks as a yellow crystalline precipitate. The flasks should now be allowed t o stand i n a cool place for 48 hrs., during which time no scum should appear on the surface. The stopper is removed, and t h e flask rotated t o loosen t h e precipitate from t h e glass, tilted t o an angle insufficient for t h e liquid t o run out. and t h e neck placed against a n asbestos pad in a Gooch crucible.2 The crucible, with t h e flask, is rapidly righted. The flask is now in a n inverted position, t h e neck resting on t h e asbestos pad. I n this position t h e flask and crucible are rotated with a slight vertical motion t o wash all t h e precipitate from t h e bottom of t h e flask. The flask is then slowly raised, permitting t h e solution t o enter t h e crucible, a n d t h e neck carefully withdrawn with a slight rotary
SODIUM
I N THE P R E S E N C E O F L A R G E A M O U N T S O F P O T A S S I U M
1
Vol.
Full details as t o 1 J . Chem. SOL, 96 (1909), 2126; 97 (1910), 1448. the preparation of the reagent, and the technique and accuracy of the method are given in the second paper. 8 This pad, which should fill one-third of the crucible, is prepared in the usual manner and finally washed with 10 cc. of 50 per cent acetone followed by 15 cc. of pure acetone in three portioas, each portion being removed separately by suction. The crucible is then dried in an air bath a t 100' for 30 min. and weighed.
