INDUSTRIAL AND ENGINEERING CHEMISTRY
January 15, 1929
Analytical D a t a on Cellulose of Alcohol-Benzene Extracted S p r u c e Wood, O b t a i n e d by T h r e e M e t h o d s (Results based on oven-dry weight of original wood)
Table XI-Comparative FINENESS SAM-DBTN. PLE No.
. .,
Va
AL-
OF
MA- CELLUTBPIAL
LOSB
Mesh
%
LIGNIN IN
CELCELLU- LUPHA-
OF
%
%
58.537.1
.. ..
As
%
..
OF
RRMAXKS
Mesh
105 40-60
68.0 43.5
..
*.
106 40-60
59.2 4 3 . 5 0.57
..
3968
103 80-100
60.0 36.80 0.60
..
.. ..
396A
104 80-100
60.2
..
*.
U. S. De t Agr., Bull. li96 Final KMnO4 bleach Final KMnO4 bleach Final KMnO4 bleach Final KMnO4 bleach
RITTER’S METHOD
107 40-60
61.2 45.0
..
396
108 40-60
61.5
44.7
..
....
396A 396A
105 80-100 106 80-100
62.5 44.3 6 2 . 3 44.3
396
103 40-60
62.7
396
104 40-60
62.6
.. .. ....
*.
.. .. ..
Final bleach Final hlearh No final No final
KMnOd KMnO4
~
bleach bleach
BRAY’Sb METHOD
396
109 40-60
62.6
.. .. 37.2 .. 46.1 .. .. .. 46.0 .. 34.6 .. .. 34.5 .. 46.0
396
110 40-60
63.0
396
111 40-60
6 2 . 5 44.7
396
112 40-60
62.7
Lost
..
..
..
35.9 35.2
396
113 40-60
6 2 . 3 44.9
396
114 40-60
62.6
45.1
..
37.5~ 36.1
396
115 40-60
6 3 . 0 44.7
..
37.7
%
%
%
%
BRAY’Sb METHOD
*.
396
396
SAMPLE
%
396
37.20 0.57
ALIN CONSUMPTION PBAC E L - OF CHLORINrt DETN. MA- C E L L U - C E L L U - LUAs No. TERIAL LOSE LOSE LOSE Total HCI
CHLORINE
LOSE LOSE Total HCI
LIGNIN
FINENESS
CONSUMPTION
SCHORGBR’S METHOD
60-80
43
.. ..
.. ..
..
Alundum crucible for weighing Alundum crucible for weighing Alundum crucible for weighing Alundum crucible for weighing Alundum crucible for weighing Alundum crucible for weighing Glass crucible throurhout Glass crucible throughout Glass crucible (too moist)
a The alpha-cellulose was gelatinous and very difficult to filter and wash. b The final KMnOa bleach was not used in any of the determinations by the crucible method. E Sample given five chlorinations; all others given four chlorinations. d Part of lignin passed through the alundum crucible du+g filtration,
The results recorded in Table I1 show that the Jena glass crucible may be used for the final washing, drying, and weighing of the cellulose residue in place of the alundum crucible. It was noticed that several of the Jena glass crucibles seemed t o lose a little weight during the operation, and it is therefore necessary to weigh them before and after use and to apply a correction where losses occur. This sometimes takes place also with alundum crucibles. Conclusions
The short method for the determination of cellulose offers the following advantages over former methods:
396
116 40-60
62.0 44.8
Average 396B 101 60-80
62.6 45.3 63.1 44.7
396B
102 60-80
62.7 44 4
396B
103 60-80
62.7 43 8
396B
104 60-80
62.9 43.9
396B
105 60-80
6 3 . 0 44.2
396B
106 60-80
63.1
396B
107 60-80
62.7
396B
108 60-80
62.7
396B
109 60-80
62.5
44.0
.. .,
.,
Average 396A 101 80-100
6 2 . 8 44.2 62.7 43.7
396A
102 SO-I00
61.8 43.2
396A
107 80-100
62 7
43 7
396A
108 80-100
62.0
44 1
396A
109 80-100
6 2 . 1 43.6
396A
110 80-100
62.6 4 3 . 5
Average
62.3 43.6
.. .. .. .. .. .. ..
..
Glass crucible throughout 36.2 36.2 21.7 Alundum crucible for weighing 37.0 2 1 . 3 Alundum crucible for weighing. 3 5 . 7 21.5 Alundum crucible for weighing 3 4 . 8 20.6 Alundum crucible for weighing 3 4 . 9 21.0 Alundum crucible for weighing 3 5 . 5 Lost Alundum crucible for weighing 0 . 6 0 3 5 . 8 21.9 Alundum crucible for weighing 0.45d 36.7 21.5 Alundum crucible for weighing 0 . 6 0 36.8 22.7 Alundum crucible for weighing 35.8 2 1 . 3 36.4 , Alundum crucible for weighing 36.9 , Alundum crucible for weighing 35.2 Glass crucible throughout 37.4 , . Glass crucible
.. .. .. .. ..
..
37.1
REMARKS
%
.
. ..
34.6 35.2
.,
..
Glass throughout crucible throughout Glass crucible throughout
35 8
1-It combines cellulose isolation and chlorine consumption and through uniform chemical action results in higher yields of cellulose. 2-The total chlorine consumed together with that forming hydrochloric acid may be measured a t the various stages of the process. 3-Chlorination is carried out under a slight hydrostatic pressure, which increases the speed of the reaction and also insures more uniform and more complete chlorination than is secured, when the sawdust or pulp is chlorinated under suction or in beakers. 4-There is less degradation of the cellulose as shown by the alpha-cellulose content. 5-The work is expedited because the lignin is removed with as great efficiency in the short chlorination period as in the long chlorination period. 6-The yields of cellulose and the chlorine consumed are practically the same regardless of the size of the particle chlorinated.
Modified Distillation Apparatus for the Chemical Engineering Laboratory’ W. L. Beuschlein DEPARTMENT OF CHEMICAL ENGINEERING, UNIVERSITY
HEMICAL engineering laboratories are not complete without fractionating equipment of some type. The theory with derived operating curves is usually followed by the experimental work. Without laboratory tests of the theoretical curves the student may hesitate to accept the establishment of the working principles. The equipment is of either the batch or the continuous type. Continuous-type equipment requires a large supply of raw material and storage space for the residue and distillate.
C 1
Received July 6, 1928.
OF WASHINGTON, S$ATTLE,
WASE.
The usual laboratory does not have such facilities. The continuous operation assures constant conditions, making i t possible to obtain excellent data. The batch still, although requiring much less liquor and storage space than the continuous type, presents the difficulty of control due to the constantly changing concentration in the kettle and column, with the time lag involved. The frequent adjustment of the reflux ratio is exceedingly difficult for students. This paper describes a combination of the two systems in which a small quantity of liquor is recirculated continuously, thus.
ANALYTICAL EDITION
44
giving constant conditions that are applicable to the batch and continuous types. Figure 1 shows the complete distillation equipment. The 30-gallon still, plate column, and condenser are of the usual
Figure 1
Vol. 1, No. 1
kettle indicates kettle concentrations. The piping from condenser to kettle converts the batch process into a continuous operation. The condensate from the condenser passes through two Venturi meters, one for the reflux and the other for the net output. With identical meters, the square root of the quotient of the manometer readings gives ihe reflux ratio, the liquids metered being of similar composition. The Venturi manometers are of the 2-liquid multiplying type. The reflux ratio is regulated by the valve A . The open vent a t B eliminates syphoning, thereby insuring a uniform flow through either meter. The operation is as follows: Fill the kettle to the 20gallon mark with a binary mixture and bring to the distillation temperature. Build up the condensate composition by returning all the condensate as reflux through operation of valve A . When the desired condensate composition is reached permit a portion to flow continuously through the sight gravity jar into the kettle. When constant conditions are assured, take readings of the Venturi manometers, kettle thermometer, and condensate hydrometer. The conditions evidently represent those obtainable at some moment during a batch run. By directing a fraction of the condensate through the cock D into a storage vessel, the kettle concentration can be decreased and a new set of conditions established. From a series of such findings, the operation of the batch type can be represented by a plot of reflux ratio us. kettle concentration. For easy reference the same relationship can be expressed with the square root of the quotient of the manometer readings plotted against kettle temperatures. Curves for continuous operation, effect of boiling rate, d a t e and thermal efficiencies as functions of amrotxiate * variables can be obtained in a similar way. The equipment described is operated with very satisfactory results, in the Chemical Engineering Laboratory of the C'niversity of Washington. I.
design. Thermometers placed in wells in the hand hole covers of each plate are useful in observing temperature changes. The thermometer placed in the vapor of the
An Examination of Possible Indicators to Determine the pH of Alkaline Solutions' F. R. McCrumb and W. R. Kenny THELAMOTTE CHEMICAL PRODUCTS COMPANY, BALTIMORE, MD.
N A number of industrial processes alkaline solutions are employed in which it is a decided advantage to be able to measure the hydrogen- or hydroxyl-ion concentration. I n many such processes it has been demonstrated that this factor is of considerable importance in itself. In other cases, while the actual pH may not be the outstanding factor, it depends on the concentration of the important constituents present, and, therefore, its measurement affords a ready method of control. Although recourse is usually made to a potentiometric method for extremely accurate results, control by colorimetric methods is usually more suitable for plant practice, in that it combines rapidity and simplicity with an accuracy sufficient for most practical purposes. A few of the processes in which such a method of alkalinity control can be applied to advantage are the manufacture of beet sugar, numerous wet processes in the textile industry, the cleaning of metal and glass, the treatment of boiler water, and the differential flotation of ores.
I
1 Presented
before the Division of Physical and Inorganic Chemistry at the 76th Meeting of the American Chemical Society, St. Louis, Mo., April 16 t o 19, 1928. Received October 17, 1928.
During the past ten years pH control by the colorimetric method has been applied to a n increasing number of industrial processes, but until recently the method has not been used to any great extent with solutions having a pH greater than 10. The lack of satisfactory indicators is probably the principal reason for this. Many indicators have been recommended in the literature and quite a few are listed by the supply houses as having pH ranges between 10.0 and 14.0, but few attempts have been made to evaluate them. This investigation was undertaken with the purpose of determining which of these indicators could be used in practice. At first glance it would seem to be a relatively simple matter to select the necessary indicators from the forty or more dyes listed as indicators with pH ranges above 10.0. Such has not been found to be the case. Experimental
Most of the dyes that were examined were obtained from commercial firms, and were listed as being sufficiently pure for use as indicators. Wherever possible, samples were se-
