Figure 1. Launder-0-Meter Used in Laboratory S t u d i e s o f F a d i n g d u r i n g Washing Operations
Germicides for y Mobile Laundries J
THOMAS H. VAUGHN, A. L. SOTIER,
AND E. F. HILL] Wyandotte Chemicals Corporation, Wyandotte, M i c h I
J. E. S131PSON2 .4XD F.RI. LEE Qfice of the Quartermaster General, United Stcites Army
THE
peacetime American Army has followed commercial practices in the kin& of products, procedures, and equipment for cleaning and pressing its clothing. This applies to both laundry and dry cleaning requirements. 411 of. this work, of course, is done in fixed installations having adequately trained personnel and suitable equipment for the purpose. 111 wartime, however, many contingenciev arise even in permanent installations far from an active theater of operation which affect the quality of the cleaning and sanitation level achieved for the garments and items. The problem of cleaning soldiers' clothing in a combat zone is more complex. Prior to World \Tar I1 the combat soldier had to depend largely on his own personal efforts to wash and dry his clothing. It goes without elaboration that this is not a good way 1 2
to keep a man sufficiently clean to maintain his morale or to give reasonable assurance against infection. World War I1 saw the advent of the rlrmy mobile laundry unit. This is essentially a small commercial laundry unit mounted on a vehicle so it can be moved into a relatively active combat zwie for its operations. I t greatly helped to furnish to front-line soldiers washing facilities somewhat like those of fixed installations. However, there are certain limitations which t'he exigencies of combat conditions place upon facilities. These limitations are chiefly the necessity to conserve heat, water, and time. It was never assumed that the mobile unit would produce results equivalent to best cornmercial standards-it was designed to serve the greatest xiuriiber of men possible with reasonably clean clothing; and the magnificent record of t,hemobile laundries shows how wel.1 they accomplished this purpofie. Other factors entered into the problem of Army laundering.
Present address, Ethyl Corporation, D e t r o i t , hlich. Present address, Orr and Bembowcr. Inc., Reading. Pa.
2054
November 1948
INDUSTRIAL AND ENGINEERING CHEMISTRY
2055
mobile laundry formula. For this purpose, a germicidal material was added to a solution containing 0.01% peptone, 0.025% sodium stearate and a standard suspension of Staph. aweus. Studies of a quaternary ammonium compound indicated an indeterminate action in the combined presence of soluble protein and an anionic detergent, such as soap-that is, in some cases only partial initial sterilization was obtained, and in some cases reversible bacteriostasis was observed. According to the Bureau, the sodium silicofluoride and sodium acid fluoride types of laundry sours were found ineffective a t several times the ooncentrations used in the souring operation and at exposures up to 30 minutes. TABLEI. LAUNDERING FORMULA FOR MOBILELAUKDRIES Another class of compounds, the phenyl mercury sal&, was reWater jected as the Office of the Surgeon General considered their use Level*, Temperature, Time, Operation Materials Used Inohes F. Minutes hazardous to personnel. Organic synthetic The foregoing considerations made it highly desirable to explore Suds detergent. 4 oz. 8 100 5 fully the possibilities of chlorine-active organic compounds, a Suds Organic synthetic detergent, 2 oe. 8 100 5 class of products known to have considerable germicidal action. None 10 100 3 Rinse Rinse Xone 10 100 3 A cooperative investigation of some typical compounds of thie Rinse Sourb 10 100 3 class was undertaken by the Office of the Quartermaster General a Untreated raw water. and the Research Department of the Wyandotte Chemicals Corb Acetic acid in a quantity sufficient t o give the desired pH, usually 5.0 poration.
Early in the war the Army adopted camouflage coloring for all of its clothing, equipage, hospital linens, etc. Even underwear and handkerchiefs were colored. Some of the field hospitals never received the colored linens but they would have been supplied with them as replacements of worn-out items had the war continued. The complete adoption of colored items meant that bleaching processes must be abandoned. The procedure which was adopted for mobile laundry use to meet these conditions is given in Table I.
DEGREE OF FADING OF OLIVE DRAB KNITTED FABRIC CAUSED BY VARIOUS TREATMENTS
It is small wonder that the Office of the Surgeon General was somewhat pessimistic concerning the sanitation level that could be Chlorine-liberating germicidal agents selected for the tksts inachieved in laundering under the limiting conditions of temperacluded: dichlorodimethylhydantoin (manufactured by E. I. du ture; small number of sudsing and rinsing operations; raw, often Pont de Nemours and Co., trade name Dactin); succinchlorihard and brackish water; and complete lack of hypochlorite mide; p-dichlorosulfonamide benzoic acid (manufactured by bleach for underwear, hospital linens, handkerchiefs, and other Monsanto Chemical Co., trade name, Halazone); Monochloitems which ordinarily receive this treatment. ramine B (sodium benzene sulfonchloramide) ; and sodium hypoThe Office of the Surgeon General requested the Quartermaster chlorite. Corp., therefore, to determine Two test fabrics both of which whether a procedure could be dewere dyed an olive drab were supA t the request of the Office of the Surgeon plied by the Office of the Quarterveloped which would give the samc General, the Office of the Quartermaster Genmaster General; these were a cotdegree of sterilization to the eral early in World War I1 directed studies to washed items as attained with ton knitted fabric, and a 50% develop suitable means of sterilizing Army hypochlorite bleach and hot water, woo1-50% cotton knitted fabric. clothing in combat areas. Preliminary studies but without a deleterious effect on Squares measuring 4 X 4 inches eliminated several important classes of germithe woolens or dyed fabrics. This were cut from these fabrics and the cidal materials. Chlorine-active organic request was predicated on the bereflectance of a single thickness of compounds appeared promising, however. Of lief that attaining a sufficiently fabric measured on the Hunter several chlorine-active chemicals studied, only low count of microorganisms in the reflectometer using green and amMonochloramine B possessed solubility, pH, laundering process would have ber filters with the large neutral fading, and chlorine-liberating characteristics marked advantages in preventing filter, and the blue filter fitted with that were practical, as determined by tests in cross-contamination of clothing the 0.5 neutral filter. A white the laboratory. Temperature, exposure time, during the laundering operation. standardized background (reflecand pH are factors governing germicidal power For instance, an outbreak of lingtivity 80.7 green, 81.0 amber, and when this chemical is used for laundry purworm among American troops 79.3% blue) was used to support poses. It was found that at pH 5.0 as little as stationed in Ireland was attributed the fabric during measurement, 25 p.p.m. of available chlorine in laundry soluto the reissue of clothing which The washing operations were tions containing moderately high amounts of had become cross-contaminated carried out in a type LHD-EF organic niaterialj will kill Staph. aureus in 5 through poor laundering practices. Launder-0-meter adjusted to 42 minutes at 38" C. Field trials of Monochlor.p.m. using pint jars containing ramine B in a mobile laundry unit at Camp 100 ml. of solution. Two test STERILIZATION IN ARMY FIELD Lee, Va., confirmed the laboratory findings to squares of fabric and 15 stainless LAUNDERING a remarkable degree. This was evidenced steel balls measuring 0.25 inch As an initial step, a t the sugby greatly reduced counts of artificially inin diameter were placed in each gestion of the Quartermaster fected swatches of fabrics laundered with solujar. Wyandotte City tap water (6 Corps, limited studies were made tions of MonochloramineB, and by greatly reto 7 grains hardness as calcium by the Bureau of Home Economduced counts of the wash and rinse waters. carbonate per gallon) was used in ics, U. S. Department of AgriWhile detailed studies looking to establishing all tests. culture, a t its Beltsville, Md., optimum concentrations of the chemical for The laundering sequence was as laboratory of several types of mathe job to be done were not undertaken, i t was follows: terials which might have the defound that about 8 ounces per 60 gallons of Suds, 0.03% alkyl aryl sodium sired germicidal action. water, used in the second clear water rinse, sulfonate, 5 minutes, 100O F . (NacThe effectiveness of various yielded the best results. The Navy has adopted eonol NR, manufactured by Nagermicidal materials was measured this procedure as part of their Specification tional Aniline Division, Allied under conditions simulating that 37-R-3, dated June 19, 1944, covering the Chemical and Dye Corp., was used of the final rinse operation of the renovation of Navy Special Clothing. in this work).
2056
INDUSTRIAL AND ENGINEERING CHEMISTRY
All results are reported in terms of E, the approximate amount of total perceived coIor difference w-hich combines all three factors indicated. The evaluation methods used have been described bv Hunter ( I ) . The fading indexes obtained with the various sterilizing agente arc given in Tables I1 and I11 along with the fading indexes for the washing and rinsing treatments for comparison. Since these indexes do not always correspond in magnitude to the visual ratings, a notation of obvious fading is included. This work indicated t h a t sodium hypochlorite resulted in txcesaive fading and could not be used for that reason. Dichlorodimethylhydantoinand succinchlorimide were found to have a very low rate of solution, and solutions were relativel? unstable. p-Dichlorosulfonamido benzoic acid could not be disbolved by any method to obtain a concentration of 250 p.p.m. of available chlorine. The 50 p.p.m. solution was obtained by addmg the calculated amount of sodium hydroxide to convert tlw material to the sodium salt. hlonochloramine B was found t o cause some fading when used a t pH 5.0 and the higher chlorine level, but at pEI 8.0 no herious fading occurred a t either concentration. The solubility of Monochloramine B \%assatisfactory for laundry UJP, as ere it. pH and stability characteristics.
TABLE11. FADINGOF 50% W O O L - ~COTTON ~ T ~ FABRICB Y GERMICIDES
p H 5.0 Control 50 p.p.m. 250 p.p.m. E VALUEB
p H 8.0
I
Sterilizing Agent
Oichlorodimethylhydantoin Succinchlorimide p-Dichlorosulfonamido benzoic acid Monochloremine B 5odium hypochlorite Washing treatment 11.1 Rinsing treatment 10.6 n Indicates obvious fading
14.3 13.4
51 . w 42,35
33.44
N o test 6 4 , 55
9.2
39.40
50 p.p,m. 250 p.p.m. Y .2
5.4 16.7a 10.5
26.Qa
109.05
36.4 21.1
No t e s t 11.3 78
I)"
Suds, 0.03y0 alkyl aryl Yodiuru sulfonate, 6 minutes, 140" F. Rinse, W7yandotte tap water, 3 minutes, 140" F. Rinse, Wyandotte tap water, 3 minutes, 120" F. Eour, sodium silicofluoride and sodium acid fluoride mixture, 3 minuteq 100' F., pH 5.0. Following the complet,jon o f t,he washing operat.ions the test, squares were stretched to their original size, placed on absorbent paper to dry, and after drying reevaluated by the refleetometer. This series of tests, consisting of washing and rinsing, gave it measure of fading due to the action of the detergent plus the ~ 1 1 ~ tomary rinses and sour. T o determine the degree of fading due to the germicidal solutions, test squares of fabric were subjected to the action of the jolutions 5 times for 5 minutes each, a t 100" F. and a t availabk ~ahlorinelevels of 50 and 250 p.p.m. and at pH levels of 5 and 8 in *the same apparatus as described for the washing operations. ,Chlorine concentration was determined by titration of iodine liberated from potassium iodine solution with standard thiosulfate eolution using st'arch as a n indicator. All pH measurements were made with a Beckman pEI meter. Adjustment was made with the laundry sour or sodium bicarbonate as required. After completing the 5 consecutive treatments in the chlorinetiberating solutions, the test squares of fabrio were dried without rinsing and evaluated with the Hunter reflectometer. ,Is a control for both the washing and germicidal treatments, a rinsing treatment series was run. This was similar to the germicidal treatment, and consisted of rinsing the squares 5 t'imes for 5 minutes in tap water at 100' F. The squares were then dried and evaluated with tho Rcflectometw. MEASUREMENT 0 F FADING RESU LTIRG FROM WASHING. RIKSING, AND GERMICIDAL OPERATIONS
Fading may consist of a change in lightness (luminous apparent reflectance), a change in hue, a change in saturatinn, or a combination of any two nr three of these effects.
23" c
-
GERMICIDAL ACTIVITY OF MOROCHLORAJIIRE B
Having tentatively selected Monochloramine B as the most promising germicide of the group tested, the object of the nexl phase of the work was to determine its characteristics and limitations \?hen used as a. germicide against a commonly occurring skin pathogen. For these tests the Army furnished a culture of Staph. aureus. The culture appeared to be normal in every way on microscopical examination. Immediately upon recpipt it wap inoculated into nutrient broth (Difco), and incubated a t 37" C Subsequently, it was transferred daily for 6 days before beginning the tests. A count made on the fourth transfer when that transfer was 24 hours old indicated 500,000,000 cells per m1. T L ~~TI E T H O DI S n .order to determine the effect of dyed and undyed fabrics, tests were cairied out in the presence of strips of knitted underm-ear fabric t h a t measured 1 X 10 cm. Fifty strips of each EabIic m-ere cut from garments furnished by the Quartermaster Gcneral's office and weighed. The undyed fabric was tht heavier and averaged 0.3566 gram per strip, while the dyed fabrir averaged 0.3177 gram per strip. Medication tubes measuring 2.5 X 10 em. were used for the tests; each received one strip of the appropriate fabric. T h t tubes were plugged with cotton and the assemblies autoclaved at 15 pounds steam pressure for 40 minutes. As controls, emptl tubes were plugged and autoclaved. Strengths of the RIonochloramine 13 solutions tested included 250, 100, 50, and 25 p.p.m. of available chlorine. These solutions
38" c
PH
23' C
PH 5.0
6.0
Vol. 40, No. 11
PH
7.0
8.0
c\I
N
5 0
Y z g
v)
Figure 2.
Germicidal Action of Monochloramine B Teats using 3-minute exposure
Figure 3.
Germicidal Action of Monoc1d.oramine T i Tests using 5-minute expomum
November 1948
INDUSTRIAL AND ENGINEERING CHEMISTRY
2057
were tested in the presence of 0.01% of peptone and 0.025% of sodium stearate, with a minimum of 1,000,000 viable cells per ml. of solution in the medication tube. The Monochloramine B solution and the one containing peptone and sodium stearate were both made up double strength, equal volumes mixed, and the resulting mixture adjusted just prior to use to the desired pH with strong hydrogen chloride or sodium carbonate to give p H values of 5.0, 6.0, 7.0, and 8.0 as measured by a Beckman p H meter. Sterile water and glassware were used throughout the test and aseptic precautions were taken to prevent contaminations. TECHNIQUE OF TESTS.With everything in readiness, and just as soon as a solution was adjusted to the desired pH, 20 ml. were pipetted into a medication tube. A series of three tubes was used for each solution at each holding temperature. The first contained no fabric, the second a strip of undyed fabric, and the third a strip of dyed fabric. The time was noted, and Figure 4. Method of Attaching Pocket-Type Swatches Inoculated with Test 5 minutes allowed for the contents of Organisms t o Garments Prior to Laundering i n Mobile Laundry Unit the tubes to come to the temperature of the water bath. The time was again uct in a mobile laundry under actual field conditions was underchecked, 0.4 ml. of a 24-hour culture of Staph. aureus addcd and taken in February, 1944, at Camp Lee, Va. These tests had a the tubes shaken. Additions of the culture to the individual dual purpose: to evaluate Chloramine B as a laundry germicide medication tubes were spaced 30 seconds apart to allow adequate under field conditions; and to determine a practical procedure time for subculturing. for evaluating laundry germicides. A t the end of exactly 3 minutes, and again at the end of 5 minA regular mobile laundry, similar to those used in the theaters utes, 1 drop from the end of a 1-ml, bacteriological pipet was used of operation, attached to the Demonstration Battalion of the to inoculate each of duplicate subculture tubes of sterile nutrient Quartermaster Board at Camp Lee was used. This mobile launbroth (Difco). The subculture tubes were incubated for 48 hours dry consisted of five separated units mounted on a trailer. Unit a t 37" C. and examined for growth. All positive tubes were ex1 consisted of an internal combustion engine coupled to a generaamined microscopically to prove t h a t the organism growing was tor which furnished electrical current for the other units and a Staph. aureus. pump which was attached to this unit. Unit 2 was a 30 X 30 inch The detailed data for this phase of the LIMITINGFACTORS. wash wheel of conventional design in which all washing and rinswork will not be given since it would involve tabulating 480 indiing operations were carried out. Unit 3 was a n extractor which vidual tube results. Only minor differences were found in killing removed water from the washed garments by centrifugal force. efficiency of the solutions in the presence or absence of either Unit 4 was a double dryer and consisted of two drums for tumdyed or undyed strips of fabric. bling the moist garments in a blast of heated air. Unit 5 was a n oil Figures 2 and 3 have been prepared to show the limiting factors fired heater which warmed the air for the dryers, and incoming of the germicidal action of Monochloramine B solutions as disTater for the wash wheel. There were no provisions for ironing closed by these tests. The shaded blocks indicate conditions perthe garments. Because woolen and cottbn garments were somemitting growth of the test organism. The open blocks indicate times washed together the temperature of the wash water wakilling conditions. kept at 100O F. FIELD T E S T S IN A MOBILE LAUNDRY FIELDLAUNDRY OPERATIOXS.Two series of tests were run, using the laundry formula given in Table I. Following the completion of the preceding bacteriological tests Series A. An anionic synthetic detergent of the amide type was on the limiting factors of Monochloramine B, a trial of the prodused in the amount of 4 ounces in the first suds, and 2 ounces in the second suds. Acetic acid was used for souring in a n amount necessary to give the desired pH. No other materials were used TABLE111. FADING OF 100% COTTON FABRICS BY GERMICIDES except the indicated amounts of the germicide. pH 5.0 pH 8.0 Series B. Low titer powdered soap, conforming to Federal SpeciSterilizing Agent ' Control 50 p.p.m. 250 p.p.m.' 60 p.p.m. 250 p.p.m. fication P-S-600, was made into a 10% stock solution and used E VALUES in the first and second sudsing operations in varying amounts as Dichlorodimethylhydantoin 29.0a 107.0a 8.3 16.4 necessitated by the soilage inherent in the loads. Acetic acid waq Succinchlorimide 22.6 97.7" 6.1 21.9 p-Dichlorosulfonamido used as the souring agent. No builders or other materials werp benzoic acid 111.0" No t e s t 1.5.3a N o test used except the indicated amounts of the germicide. Monochloramine B 32.15 186.0" 12.6 12.6 Sodium hypochlorite 205.0" 329.0a 49.90 205.5s Addition of Monochloramine B was made usually in one of the Washing treatment 7.7 Rinsing treatment 6.7 rinses. The regular water supply at Camp Lee was used throughIndicates obvious fading. out the test. This varied between 1.5 and 4.5 grains of hardness pcr gallon.
2058
INDUSTRIAL AND ENGINEERING CHEMISTRY
Figure 5. Measurement of pH of Detergent arid Germicidal Solutions in the Field
Each wash load weighed 60 pounds ( + 2 pounds) and \\-as inado up of the following xoiled salvage ~ o o items: l four blankets, twelve pairs trousers, twenty-fivr pairs socks, and eight woolen blouses. Also, each wash load had one piece of 50CGcotton and 50% wool olivv drub uiiderlvcar knit fabric included to give an indication of fading. The mator capacity of the u-ash wlieel containing 60 pounds of dry weight salvage garments was 38.5 gallons a t the 8-inch level for the suds operations and 42.5 gallons a t the 10-inch level foi, the rinsing operations. >\IEASURING GERRfICIl).&l. .kCl'ION ;\CCOUPLISHDD B Y L.4lJSDER-
OPERATIONS. The salvage garments w x e rloi sterile a t tile start of the tests but there was reason to believe that they were not heavily contaminated. It as decided that, primary emphasis would be placed on t,he degree of disinfection of artificially infected swatches pinned to the blouses. Secondary emphasis was to be given to plate counts of the liquids from the various operations. Six slants of Escheridhia coli and six slants OS Bacillibs suhtilis, 5 days old, were furnished by the Bureau of Human Kutrition and Home Economics Laboratory, Department, of Agriculture, Beltsville, Md. Pocket-style swatches measuring 2.5 X 2.5 inches, made of 50% wool and 50% cotton knitted fabric, were inoculated on the inside of the pocket with 1 ml. of a mixed suspension of test organisms prepared by scraping the surface growth from the twelve slants into 250 ml. of freshly sterilized nutrient broth (Difco). The inoculated swatches were air-dkied a t room temperature overnight. One swatch was pinned inside the yokc of each of eight blouses used in each wash load. One swatch was removed at the end of each washing operation, and using aseptic techniques, =as introduced into a bottle containing 75 1111. of sterile nutrient broth and hand shaken for 30 seconds. Duplicate plates of decimal dilutions were prepared and incubated for 48 hours a t room temperature (25 ' * 3' C.) before counting. Counting of the plates was done with a transilluminat,ed colony counter. Plate counts of the liquids from the various washing operations were determined likewise. All bacteriological work except incubat,ing and counting was IKG
Vol. 40, No. 11
done inside a tent set up near the mobilc laundry unit. Difco's nutrient agar was the plating medium used. This was melted in pans of boiling water on field stoves. Alcohol lamps were used for flaming the lips of the bottles of agar, and for flaming pipet tips. Air contamination although not eliminated, was held to a minimum. Heavy rains preceding and during the field trials assisted in minimizing airborne contaminations. Rrot,h tubes were inoculated with appropriate dilutions of the same liquids used for plate count determinations in some but not all cases. E As a test of the viability of organkms on the inoculated s\vat,ches, several mere planted in jars of nutrient broth a t t,he end 01each day's run and incubated. I n every case these tests were positive; thij showed that the inoculated swatches contained living organisms. PEHFORRIAKCE OF ~IOSOCHLORAMIKE 13. In all, nineteen individual test runs were madc. Only two, which are typical of the entire series, are presented (Tables IT' and V). The data shown in t,hese tables indicate a st.riking reduction in count folloning the introduction of the germicide. The nineteen individual runs that were made were about equally divided between the soap and synthetic detergent series. r\;o significant differences Tvere found between these two detergents. Only minor differences were found when the germicide was added to either the second rinse or the sour rinse, provided the amount,s added gave equivalent concentrations in the final operation (sour rinse). Generally, slightly lower count,s resulted when the chemical went into the sour rinse. When added t o the first, rinse counts wers higher. In every run there was close correlation between counts on the liquids a,nd counts on the swatches of fabric corresponding t o those same liquids. The results on t,he inoculat,ion of broth tubes are not shown in the tables. These agreed vie11 n-ith t,he plate counts and hardly merit special presentation. GENERAL DISCUS SlON AND COKC LU SION S
This work has shon-n that it is possible to include Moriochlorainine 13 in regular Army washing operations and secure the germicidal benefit of this chemical without increasing the number of operations, and a t no cost beyond that of the chemical used. This research program was not extensive enough to answer fully all questions concerning minimum quantities of Alonochlo-
TABLE
IT'.
B A ~ T E R I CAOLU N T O F S\TATCIIES-~ERIES 4 S o Germicide Added __ 1313 Bact. count
Operation
T:irst suds Second suds First rinse Second rinse (germicide added here) Sour rinse Extractor Thyer
TABLE
\'.
6.40 8.60
7.15 6.80 5.25
.. , .
BA4CT~RI.4L COUNT
20,000 27,200 300 4,320 2,330 1,780 2 30
OF
8.0 Oz. of Monochlo-
ramine B Added pH Baot. count
6.50 6.40 6.70
41,600 21,600 36,000
z.05
96 4 80 4
J. 20
.. ..
SWATCHES-SERIES 8.0
Operntion
Dryer
N o Germicide S d d e d pII Bact. count
R
of hfonochloramine B Added pH Bact. count 02.
INDUSTRIAL AND ENGINEERING CHEMISTRY
November 1948
ramine B needed, or at what step the germicide should be added t o give maximum benefits. However, it seems that 5.5 ounces for 42.5 gallons or 8 ounces for 60 gallons of rinse water is not far from the optimum, and this should be used in the second clear water rinse. In normal laundry operation this procedure gives approximately 250 p.p.m. available chlorine in the second rinse with enough solution being retained by the load to give about 50 p.p.m. in the sour rinse. Because of the low p H of the sour rinse germicidal action continues through this operation. As a result of this undertaking the Navy has included a Monochloramine B treatment in their specification covering the renovation of Navy Special Clothing ( 2 ) . This specification calls for 8 ounces of Monochloramine B for each 60 gallons of water used in the second rinse immediately preceding the sour rinse. Temperature and p H are just as important to the germicidal action of Monochloramine B as is concentration. Excessive amounts of the chemical at low p H values will cause fading (bleaching), and could result in loss of tensile strength. No special studies on the loss of tensile strength mere made in this program because of time limitations. This work suggests the possibility of using Monochloramine B in commercial laundries in cases of emergency, although, under normal conditions commercial laundries rarely need a germicide. From this investigation the following conclusions were drawn: Of the chlorine-liberating chemicals studied, only Monochloramine B possessed solubility, pH, and chlorine-liberating characteristics that seemed practical for use in a mobile field laundry. When Monochloramine B solutions were used at available chlorine levels of 250 p.p.m. at 100" F. and a p H of 8, and 50 p.p.m. a t 100" F. and a p H of 5 , fading was negligible on olive drab 50:50 cotton-wool knitted fabric after five washing operations lasting 5 minutes each. On 100% cotton fabrics negligible fading occurred under the same conditions a t 250 p.p.m. but visible fading was observed at the 50 p.p.m. level a t a p H of 5.0. For the 100% cotton fabrics a third rinse would reduce the Monochloramine B content to a safe level in the sour stage. Laboratory studies on Monochloramine B solutions, containing concentrations of organic material comparable with laundry
2059
rinse waters, have indicated sufficient germicidal action t o kill Staph. aureus in 3 minutes a t 23 O C. and at p H 5.0 when used a t a n available chlorine level of 50 p.p.m. If the p H is raised to 6.0, 100 p.p.m. of available chlorine are needed. With a contact time of 5 minutes and a t 38" C., 25 p.p.m. of available chlorine kills a t p H 5.0, and 50 p.p.m. kills a t p H 6.0, 7.0, or 8.0. Studies in the field with a n Army mobile laundry unit yielded data showing a marked reduction of bacterial count when Monochloramine B was used in the laundering operations. This was evidenced on both laundered fabric and in washing and rinsing waters when E. coli and even such resistant organisms as Bacillus subtzlis were the test organisms. The studies indicate that Monochloramine B is equally effective when the detergent used is soap or anionic synthetic detergent. Maximum benefit can be expected in backrial destruction when the chemical is used in the second clear water rinse. ACKNOWLEDGMENT
The authors wish to express their thanks to the many people who cooperated on this project, especially Virginia Nutting and Ruth Foran of the Research Department, Wyandotte Chemicals Corporation, who ably assisted in the laboratory phases of the investigation; Dorothea Klemme and Agnes Baldwin of the Bureau of Human Kutrition and Home Economics Laboratory, U. S. Department of Agriculture, who assisted in bacteriological work of the field tests; M. R. Wainer of the Quartermaster Board, and A. M. Gruber and W. W. Peck of the Quartermaster Corps, who gave valuable aid and assistance a t Camp Lee; V. A. Vaccare who was in charge of the laundry unit during the tests; G. J. Lynch who acted as test recorder; and Edward L. Butler, laundry specialist, attached to the Surgeon General's Office, who assisted in planning the field tests. LITERATURE CITED
Hunter, R. S., NatE. Bur. Standards, Circ., C429 (July 30, 1942). (2) U.S. Navy, Specification 37-R-3, June 19,1944. (1)
RECEIVEDApril 23, 1947.
High Pressure Laboratory Flow Apparatus V.
N. IPATIEFF, G . S. MONROE,
AND L. E. FISCHER Universal Oil Products Company, Riverside, I l l .
T h e laboratory flow plant described has given satisfactory results for high pressure reactions, such as the synthesis of methanol from hydrogen and carbon dioxide and the conversion of benzene and benzene-methane into toluene.
VIEW of the growing importance of high pressure operation h I in the process industries, the need for small scale high pressure apparatus for laboratory research is apparent. Such laboratory equipment should be capable of operating under conditions comparable with those employed in industrial practice. The reduction t o laboratory scale, however, frequently meets with difficulties in t h a t parts of the apparatus, such as pumps, pressure controllers, etc., tend t o operate more erratically when reduced to smaller proportions. This condition imposed by small scale operation requires, in some instances, a departure from the usual commercial or pilot plant practice, as, for example, the delivery
of high pressure gas t o the reaction system by displacement by liquids from storage cylinders rather than by compressors. The present paper describes a high pressure laboratory flow plant t h a t has given satisfactory results for high pressure reactions, such as the synthesis of methanol from hydrogen and carbon dioxide (1) and the conversion of benzene and benzene-methane into toluene ( 2 ) . DESCRIPTIOY O F APPARATUS
The high pressure flow plant was designed to process, catalytically or thermally, normally liquid or gaseous materials, or combinations of both, a t pressures up to 13,000 pounds per square inch and at temperatures up t o 565' C. T h a t part of the equipment which withstands pressure is enclosed within iron barricades 0.25 inch thick. Peep holes, covered with bulletproof glass, permit the observation of instrument read-
