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
860
Since the results of the previous experiments showed considerable reduction in the yield of resorcinol when t h e fusion was conducted for 2 hrs. at temperatures below 310', it was thought t h a t by increasing t h e fusion period a corresponding increase in t h e yield of resorcinol might be obtained. Accordingly, the tubes were charged with the amount of sodium benzene m-disulfonate and sodium hydroxide used in the previous experiments, and t h e mixture fused a t 270'. At the end of 4, 6, and 8 hrs., respectively, a tube was removed, suddenly cooled with "water, and- analyzed. An identical -experiment was carried out a t 290' and the results obtained are given in Table IV, and graphically in Fig. 2 , Curves a and b. TABLEIV-EFFECT
OF
Temp. of ?usion C.
NO.
. . . . . . . . . . 270.
VARYINGFUSIONPERIODAT 270' AND 290O C.1 CeH&OsNa)n Yield of Resorcinol Found Grams Per cent Grams Per cent 2.5296 3.0675 3.1983 3.1820 3.2637 3.2311 3.1443 3.0560
I 2 3 4 S... 6 7
.......... 270 .......... 270 .......... 270 ...... 290 .......... 290 .......... 290
46.0 55.7 58.1 57.9 59.3 58.7 57.1 55.5
B .......... 290 1 Ratio CaHa(S0sNa)a : NaOH = 1 : 16.
'
3.0807 1.9470 1.4950 1.3950 1.5501 1.3477 1.3242 1.3261
21.9 13.8 10.6 9.9 11.0 9.5 9.4 9.5
Fusion period 2 hrs.
It appears from this table t h a t even with longer fusion periods t h e yields, although improved, are not quite as good as those obtained a t 310'. It is, therefore, reasonable t o conclude t h a t 310' is the optimum fusion temperature.
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No. 9
ments in which the amount of water was t h e only variable are given in Table V and graphically in Fig. 4.
No. 1 2 3 4 5
TABLEV-EFFECT OF VARYING AMOUNT OF WATER1 Amount of Water Added Per cent of CaH4(SOsNa)z Found Total NaOH Yield of Resorcinol Used Grams Per cent Grams Per cent
........... 10 ........... 20 ........... 30 ........... 40 ........... 50
' 1 Ratio CbH4(SOsNa)s Fusion period 2 hrs.
2.8057 51.0 1.3279 9.4 2.4908 45.3 1.2600 1.2182 9 8.7 .0 1.9632 35.6 1.4315 1.4470 10.2 26.0 13.7 0.7525 1.9765 14.0 NaOH = 1 : 16. Temperiture 310" C.
, It is evident t h a t water tends t o cut down the yield of resorcinol. I n conducting an alkali fusion of sodium benzene m-disulfonate for the production of resorcinol no water should be added, although judging from t h e nature of the curve from 2 t o 4 per cent of water would not greatly reduce the yield. Our results on the effect of water bear out t h e statement of Binschedler and Busch' t h a t t h e fusion must be conducted with the addition of as "little water as possible." SUMMARY
Using an apparatus especially designed for carrying out of alkali fusions of aromatic sulfonic acids, a study was made of the various factors affecting the fusion of sodium benzene m-disulfonate with sodium hydroxide for the production of resorcinol, including temperature, time, ratio of sodium hydroxide to sodium benzene m-disulfonate, and concentration of water in the fusion mixture. The results indicate t h a t 310' is the best fusion temperature, 2 hrs. the best fusion period, 14 t o 16 moles of sodium hydroxide t o I mole of sodium benzene m-disulfonate t h e best fusion mixture, and t h a t water tends t o reduce the yield of resorcinol. *
THE PREVENTION OF SUGAR DETERIORATION BY THE USE OF SUPERHEATED STEAM IN CENTRIFUGALS By Nicholas Kopeloff LOUISIANA S U G A R EXPERIMENT STATION, N E W ORLEANS,LA Received June 11, 1920
0
20
l0
30
40
50
Per Gent Water in Na OH FIQ. 4-cONCENTRATION
OF
WATER
AS
EFFECT O F WATER I N THE
RELATEDTO RESORCINOL YIELD CHARGE UPON THE R E -
Ymm-Since it i s a common practice in making alkali fusions of aromatic sulfonic acids t o add water t o t h e sbdium hydroxide, in order t o make the melt less viscid and, therefore, more easily discharged from the fusion kettle, i t was considered very important t o study the effect of the presence of water upon the yield of resorcinol. The results of experiSORCINOL
The deterioration of manufactured cane sugar has been the subject of considerable investigation t o which reference has already been made.2 Following a study of the most important single group of microorganisms, the molds, responsible for sugar deterioration, the writer prepared a chart whereby it was possible t o predict the keeping quality of a sugar.s It remained t o devise some means of eliminating the causative organisms in order t o prevent sugar deterioration. Shorey4 and others have suggested the use of superheated steam in the centrifugals, but so far as we have been able t o ascertain no controlled experiments have been conducted to test out t h e efficiency of such an agent. Unfortunately, i t was not possible t o arrange for an equipment in our sugar house and mill which would permit of such a study, and i t was due t o Assistant Director W. G. Taggart, who devised an apparatus t o be used in the laboratory 1 LOC.
cit.
a Kopeloff and Ropeloff, Louisiana Experiment Station,
(1919). 8
4
Louisiana Experiment Station, Bulletin 1'70 (1920). J . SOC.Chem. Ind.,-l7 (1898), 555.
Bulletin 166
Sept., 1920
T H E J O C R N A L O F I N D U S T R I A L A N D ENGINEERING CHEMISTRY
centrifugal, t h a t the present experiment was made possible. The centrifugal used was a n 11-in., 1915 model, N o . 2 , made by t h e International Instrument Company of Cambridge, Mass. The jacket had a diameter of I I in. and a depth of 3.5 in. A larger concave trough 15.25 in. in diameter and 6.5 in. deep caught t h e molasses. The device used for superheated steam was simple in construction, consisting of a half-inch intake pipe with two arms ( 3 / 8 in. diameter), one inside t h e basket,, stopping 1.5 in. from t h e bottom, t h e .other between t h e basket and t h e trough. These were made of copper, sealed off at t h e lower end, and had a slit in the side facing t h e surface of t h e sugar. The device was securely attached b y means of screws t o the outside trough. An autoclave was used as a source -of steam, t h e outlet pipe being connected by a nipple and thick rubber tubing with a Io-in. superheater (or heating spiral such as used with an Abbe refractometer), which in t u r n was connected with rubber tubing t o t h e device in t h e centrifugal through a hole in the cover, t h e latter being kept closed during t h e course of the experiment. Fig. I is a diagrammatic illustration of t h e apparatus used.
86 I
Upon stopping t h e steam and centrifugal t h e temperature of t h e sugar was I j5" F. (68' C.). Naturally, t h e sugar cooled very rapidly and doubtless t h e heat attained while t h e superheated steam was being applied was considerably in excess of this figure. T h e sugar was washed as white if not whiter than. with a jet of water such as is ordinarily used. Samples of t h e sugar and t h e molasses coming from it were taken in sterile containers for bacteriological analysis. The same procedure was repeated with a 1.5 in. layer of massecuite previously heated t o 136" F. (58" C.) for about 5 min. and a t about I Z Z O F. (jo" C.) for I O min. more. I n this case t h e steam treatment was interrupted owing t o a bend in the tubing which blew off one of t h e connections. At t h e end of t h e treatment t h e temperature of t h e sugar was 158" F. ( 7 0 " C.). The samples taken above were plated out in three dilutions on Kopeloff's agar,l incubated a t 30" C., and read after 3 and 7 days. The data are presented in Table I, in which are recorded t h e closely agreeing averages of quadruplicate determinations of each of t h e three dilutions. TABLEI-EFFECT OF SUPERHEATED STEAMIN THE CENTRIFUGAL ON NUMBEROF MICRO~RGANISMS IN SUGAR BACTERIA MOLDS PER CENT REDUCTIONS TREATMENT Per Gram Per Gram Bacteria Molds .Untreated. 40' C . . 1,500,000 550 8,000 10 9b147 Steamed. Molasses. 235,000 275 84.34 50.00 Untreated, 58' C . . 200,000 110 14,000 10 9j:Oo 9O:bi Steamed'. 1 Steam treatment interrupted.
.. .......... ......... .. ..........
FIG. 1-DIAGRAMOF DEVICEFOR USINGSUPERHEATED STEAMIN LABORATORY CENTRIFUGAL a-autoclave; b-superheater; c-intake pipe with arms for delivering steam on inside and outside of basket; d-basket; e-jacket
Confectioners' crystals, which are large in size, were sterilized and coated with a blackstrap molasses which was heavily inoculated with micro6rganisms such as Aspergillus Sydowi Bainier, Aspergillzcs niger, Penicillium expansum, B . v d g a t u s , B. megatherium, B. mesentericus, and all t h e bacterial colonies developing from 1 5 0 plates poured from Cuban raw sugar. A massecuite of medium density was prepared and t h e Centrifugal steamed out after receiving a swabbing with alcohol containing carbolic acid. The procedure was then as follows: The autoclave was run u p t o 2 2 lbs. pressure or a temperature of 263' 17. The massecuite was heated t o 104" F. (40" C ) for about I O min., and pouredinto t h e centrifugal basket until i t formed a layer three-fourths of an inch deep. The superheater was started with a Bunsen burner (asbestos being used t o protect t h e rubber tubing) t o get it well heated before the steam was added, then t h e centrifugal was put in operation (attaining a maximum of 3,000 r. p. m.) and t h e steam turned on for 3 min.
It will readily be seen t h a t in t h e first instance t h e untreated massecuite had 1,500,ooo bacteria and 550 molds per g., while t h e treatment with superheated steam resulted in reducing t h e content t o 8,000 bacteria and I O molds per g., a diminution of 99.47 per cent of t h e bacteria and 98.28 per cent of t h e molds, respectively. This means an efficiency in t h e decimation of t h e microorganisms which is remarkable and the significance of which will be discussed in detail presently. The molasses from this sugar had ag5,ooo bacteria and 2 7 j molds per g., a reduction in 84.34 per Cent of t h e bacteria and jo per cent of t h e molds. This is again proof of the sterilizing effect of superheated steam, since i t may be inferred t h a t t h e heat attained for the short time necessary t o wash the molasses from t h e sugar was sufficient t o kill more t h a n three-fourths of t h e bacteria and one-half t h e molds. Furthermore, this is of practical value from t h e standpoint of t h e keeping quality of t h e molasses. We have previously referred t o t h e unsanitary conditions under which most molasses is kept, frequently in tanks literally covered with a mat of mold mycelium. I t is logical t o suppose t h a t where t h e original mass infection may be so materially reduced, t h e keeping quality of such a product may be greatly enhanced. Moreover, we have here an advantageous substitute for wash water which is frequently of questionable character and often responsible for a heavy inoculation with microorganisms. Moreover, these d a t a indicate t h a t by far t h e larger 1
LOC.cit.
86 2
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
proportion of microorganisms contained in t h e massecuite leave t h e centrifugal in t h e wash. Therefore, when it is the practice t o separate t h e molasses and t h e wash, a less contaminated molasses is procured with undoubtedly improved keeping quality. I n this connection a digression may be permitted, which may be worthy of trial: namely, where molasses is not fermented and it is desired t o keep i t for some time, we would suggest the use of a thin layer of oil on t h e surface. This would prevent a mass infection a t t h a t vulnerable point and could be easily removed. The oil in this way need not affect either the quality, odor, or taste of t h e molasses. On the other hand, where mold growth already covers the surface i t might be advisable t o spray with toluene, which is cheap enough t o be economical, germicidal enough t o kill the molds, and volatile enough t o be removed within a few days by exposure t o the air. Since the pressure of time does not permit of the opportunity of developing these suggestions in t h e sugar mill, they are advanced for what they may be worth. Returning t o t h e latter half of Table I, i t will be seen t h a t where the massecuite was heated t o 122' F. (jo" C.) the untreated sample contains only about one-eighth t h e number of bacteria and one-fifth t h e number of molds present in the massecuite heated t o 104' F. (40' C.). This means t h a t a partial sterilization has already been effected. The treatment with superheated steam was interrupted and t h e final results show t h a t 93 per cent of t h e bacteria and 91 per cent of t h e molds were eliminated. It was t o be expected t h a t these figures would be somewhat below those obtained in t h e first instance, since t h e partial sterilization referred t o probably eliminated the least resistant organisms and left a flora relatively more resistant than t h e one originally present. The interruption of the steam treatment must have been responsible for some loss in efficiency. Finally, t h e difference may be ascribed t o the fact t h a t t h e layer of sugar in this instance was twice as thick as t h a t used i? t h e first instance. It is t o be expected t h a t four important factors would be operating in such an experiment, 'uiz., temperature of steam, duration of application, thickness of layer of massecuite, and speed of centrifugal. From the d a t a set forth i t is evident t h a t the use of superheated steam under t h e conditions of t h e experiment was instrumental in almost entirely eliminating t h e microorganisms present, the important consideration being t h a t this was accomplished without increasing t h e moisture content of t h e sugar perceptibly, as in washing with water. As a matter of fact, under mill conditions it might be anticipated t h a t even better results might be obtained where higher temperatures might be so readily available. The procedure has the merits of ( I ) Simplicity in construction and operation. ( 2 ) Economy in equipment, installation, and operation. (3) Efficiency under all conditions. (4) Yielding a cleaner wash.
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I n working out a chart for predicting t h e keeping quality of sugar it was shown t h a t two factors, moisture ratio and degree of infection,l operated simultaneously. It is obvious, therefore, t h a t such a striking reduction in mass infection can be effected by the use of superheated steam in t h e centrifugals t h a t the keeping quality may be greatly enhanced even where t h e moisture is somewhat more $han i t should be. For example, a sugar having a moisture ratio of 0.08 will deteriorate when 10,000t o IOO,OOO mold spores per gram,are present. A reduction of 98 per cent, however, bringing t h e content down t o about 1,000 spores per gram would make this sugar safe even though t h e moisture ratio increased t o as much as 0.14 t o 0.16. Thus it may be said t h a t in t h e investigations on sugar deterioration carried forward in this laboratory, t h e study of t h e microorganisms and their activities, which made possible t h e prediction of the keeping quality of sugars, has found its logical completion in t h e development of an adequate means for eliminating t h e microorganisms and consequently preventing sugar deterioration. However, i t must be emphasized again t h a t the sugar must be properly handled under sanitary conditions with a minimum possibility of absorbing moisture in order t o ensure its safe keeping, since, under optimum conditions, t h e microorganisms soon propagate rapidly enough t o become detrimental. SUMMARY
I-A
simple, economical, and efficient method has been developed for employing superheated steam in laboratory centrifugals. 2-By means of this treatment t h e bacterial content of sugar has been reduced 93 t o 99.5 per cent, and t h e number of mold spores has been reduced 92 t o 98 per cent. The microorganisms in molasses are reduced similarly t o a lesser extent. 3-This elimination of microorganisms improves t h e keeping quality of t h e sugar as well as t h e molasses. 4-With superheated steam treatment, the practice of separating molasses and wash results in a considerable reduction of microorganisms in molasses, with consequent improvement in its keeping quality. THE CAUSE AND PREVENTION OF AFTER-CORROSION ON THE BORES OF FIREARMS',' By Wilbert J. Huff EXPLOSIVES CHEMICAL LABORATORY, PITTSBURGH EXPERIMENT STATION, BUREAUOF MINES,PITTSBURGH, PA.
During t h e past war t h e Bureau of Mines was requested t o investigate t h e causes of the after-corrosion which sometimes appears on t h e oiled bore surfaces of firearms subsequent t o the use of high-pressure smokeless powder^.^ Experimentation had hardly begun when the armistice was signed, but because of t h e importance of the problem and the wide general in1
L O C . cit.
2
Published by permission of the Director, U. S. Bureau of Mines.
a Read before the Section of Physical Chemistry at the 59th Meeting
of the American Chemical Society, St. Louis, Mo., April 12 to 16, 1920. 4 Although this study was undertaken primarily in an advisory capacity, this Bureau is interested in the problems of corrosion as a part of its work lor the preservation and proper utilization of our mineral resources.
)
