June, 1916
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
the instructor after which t h e student was expected to devise his own methods for solution. The instructor answered specific questions b u t refused t o suggest an outline or general plan of procedure, requiring the student t o work out his own methods from t h e literature. A full discussion and exchange of methods among t h e students in t h e laboratory was, however, encouraged. Experience has shown t h a t students attack such problems in a wide variety of ways a n d frequently with varying results. These are criticized and amended in class discussions a t t h e end of each semester. PROBLEM given a sample of crude California petroleum, obtain t h e yield of kerosene oil which complies with t h e requirements of the state law. Requiijements: An examination of t h e state law, reference t o t h e literature of petroleum refining a n d familiarity of the student with the varying effects of t h e rate of distillation, t h e design of distilling apparatus, t h e effects of acid a n d alkali treatment, t h e removal of water from oily distillates, and t h e various forms of oil testing apparatus. P R O B L E M 11-Given a sample of coal-gas t a r a t a local cost of 6 cents per gallon. determine t h e yield of creosote complying with t h e specifications of the city of Seattle 2nd t h e cost per gallon. f . 0. b. plant, of t h e creosote. Requirements: The specifications of t h e city for creosote, t h e distillation of t h e coal t a r . computation of fractions and t h e derivation of the process of distillation, t h e analysis of t h e creosote by t h e official method. a s t u d y of t h e uses and values of t h e by-products such as light oil 2nd pitch, t h e selection of a unit charge for commercial operation, a field study of a Barrett plant, and itemization of costs of production. P R O B L E M 111-Prepare a bituminous enamel containing 2 0 - 3 j per cent carbonaceous matter insoluble and j j-6 j per cent ash. with physical properties specified by t h e United States War Department. Requirements: A study. of t h e commercial pitches, methods of analysis of bituminous materials and selection of a paint filler. P R O B L E ~ Z I Iv-Determine which one of two commercial boiler compounds shall be selected t o prevent scale formation in t h e University Power Station. Requirements: Analysis of scale, of feed water and of t h e boiler compounds; a study of t h e causes and prevention of scale formation and t h e application of t h e d a t a t o the given case. A description of t h e problem has already been published in THIS J O U R X A L ,
8 (19161, 435. P R O B L E X v-Determine t h e effect of blending Portland cement with Washington tufa. Requirements: Reference t o the literature of blended cement products; testing of cement b y standard methods; and a study of cement specifications. P R O B L E X v-Determine t h e proportion of cement, sand and gravel in concrete. Requirements: Method of mechanical analysis; grading of aggregate; specific gravity determinations; chemical analysis of cement; 2nd computations.
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P R O B L E X vII-Determine t h e effect of a d d i n g lime a n d sand t o a plastic red burning clay. Requirements: Methods of clay testing; study of range of vitrification; grinding and mixing operations. P R O B L E M vm-Classify the oil obtained from samples of Philippine nuts. Requirements: Extraction of oil from nuts; comparison with the known constants of f a t t y oils; and t h e relation of constants t o uses of t h e oil. P R O B L E M Ix-Determine t h e yield of rosin in western yellow pine. Requirements: Methods of sampling; extraction by various solvents; and efficiency of commercial solvents. P R O B L E M x-Determine t h e efficiency of t h e recovery of ammonia in t h e extraction of rosin from Douglas fir. Requirements: Separation of rosin and humus; Kjeldahl determinations; removal of ammonia from wood; and computations. P R O B L E M XI-Devise a method for t h e extraction of cedar oil from t h e destructive distillation of Port Orford cedar and determine t h e nature and probable uses of t h e residues of t h e distillate. Requirements: Methods of d a m distillation a n d of vacuum distillation; study of literature relating t o Port Orford cedar oil; determination of constants of oil; study of mood tars and their uses. P R O B L E M xII-Prepare a rosin paint drier soluble in raw linseed oil. Requirements: Preparation of metallic resinates; methods of paint testing; and cbmmercial requirements of driers. During t h e present year similar problems dealing with t h e study of cactus, wood humus, potash salts, recovery of iodine, cost of manufacture of hypochlorites, etc., have been undertaken. I t is apparent t h a t t h e problems are capable of great diversification, which adds t o the interest. The chief objects in view are t o throw t h e student upon his own resources, make him acquainted with chemical literature and force him t o make use of t h e tools of knowledge already in his possession. LABORATORY OF INDUSTRI 4~ CHEMISTRY UNIVERSITY OF WASHIRGTON, SEATTLE
AN UNUSUAL EXPLOSION IN CONNECTION WITH POTASSIUM CHLORATE By FLOYD E ROWLAND
Received May 3 , 1916
There was nothing unusual about t h e explosion itself, but the manner in which it occurred is well worth mentioning 2nd bringing t o t h e attention of all who ha1-e occasion t o use pestles which have wooden handles. Everyone knows t h a t disaster is sure to follow when potassium chlorate a n d sulfur are ground together; b u t t o have 2 perfectly clean mortar and pestle suddenly explode with great violence, when one is grinding a n inert substance like pumice stone, makes one pause and wonder why. A pestle and a n 8-inch mortar were thoroughly cleaned and about fifteen pounds of potassium chlorate were ground with no disastrous results. The mortar
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and pestle .were washed and dried. A few days later some crushed pumice stone was required in the laboratory and t h e same mortar and pestle were used. A loud explosion resulted. The mortar and pestle were broken into many pieces and thrown violently about t h e room. One piece passed through a window scarcely shattering t h e glass. The room was filled with sulfur dioxide a n d fine particles of sulfur were scattered over t h e floor and table. .4n examination of t h e pieces of t h e mortar showed no traces of sulfur b u t quite large quantities of sulfur were found adhering to t h e fragments of t h e pestle. The wooden handle of this pestle had been sealed into the ball p a r t with sulfur. Evidently a small amount of t h e potassium chlorate worked into t h e crevice with t h e sulfur a n d caused i t t o explode when given a sudden jar.
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a s they go. but filtration is slow and small differences in the decolorizing powers of charcoals are difficult to detect, even with the aid of a colorimeter. When t h e operation is repeated on a manufacturing scale, these small differences become magnified and may mean a considerable difference in the final product. T h e same argument applies, though perhaps t o a lesser degree, t o the testing of charcoal on argols solution and on various pharmaceutical products. The use of a n alcoholic solution of caramel, a s suggested by Laube, is open to t h e objection t h a t t h e solvent is volatile and t h e solution.cannot, therefore, be used a t high temperatures. If an aqueous, instead of a n alcoholic, solution of caramel he used, trouble is experienced in obtaining clear filtrates, and, moreover, t h e solution will not keep. An aqueous solution of a n aniline dye gives unreliable results owing t o t h e fact t h a t many charcoals on t h e market contain. appreciable amounts of soluble ash, and t h e alkalinity of this ash produces color changes which vitiate t h e results obtained. A method has been devised in these laboratories, which is very rapid and which enables charcoals to be classified with great ease a n d accuracy according to their decolorizing efficiency. A solution of Aniline Red, Soudan 111 (oil soluble), in kerosene is used. The strength of t h e solution is largely a matter of choice, but we have obtained t h e most satisfactory results with a 0 . 0 2 5 per cent solution ( 0 . 2 5 g. per liter). One hundred cubic centimeters of this soluF ~ ~ a v a n roP a BIOIIRN MORTAR A X D PRPTLE tion are measured into a 1 5 0 cc. beaker, 5 g. of t h e An examination of other pestles of t h e same type charcoal are added a n d t h e beaker placed on a boiling showed them to contain a s much as I O to 20 g. of sulwater bath in such a manner t h a t t h e beaker is entirely fur. enveloped in steam but does not dip into t h e water. This explosion might have been more disastrous had The charcoal is kept in suspension by frequent stirring not t h e mortar been used a t this time for grinding t h e a n d a t t h e end of ten minutes t h e beaker is removed pumice stone, as, in a few days i t would have been from t h e water bath a n d t h e mixture filtered. The used again to pulverize more potassium chlorate, kerosene solution filters very rapidly and comes and with t h e excess chlorate t h e explosion would have through clear a n d bright. I t s color is compared with been more violent. a scale prepared in t h e following manner: It certainly is not generally known t h a t t h e handles One hundred cubic centimeters of t h e kerosene of these pestles are sealed in with sulfur, for if it were solution of Soudan I11 are treated with I g. of a charcoal they would never he permitted in t h e laboratory. of average quality. The solution thus obtained is The pestle was of German make and whether or not they still employ sulfur for this purpose is difficult given the value IO. A second solution, obtained b y t o say. If a n y companies in this country are using treatment with 2 g. charcoal, k g i v e n t h e value 2 0 , sulfur for this purpose they should substitute in its a third, obtained with 3 g. charcoal is numbered 30, place some inert cement. Laboratories should bar and so on up to 100. The scale t h u s obtained is, of course, of a purely t h e use of this type of pestle until t h e sulfur has been arbitrary nature, b u t i t has, none t h e less, a real replaced by some safe material. meaning, Thus, if, by treating the standard solution UNlVBRSLTY 01 I'Glh-Ol% URBANA with j g. of charcoal according t o the method above described, a solution is obtained of the same depth of A RAPID METHOD FOR COMPARING THE DECOLORcolor as t h a t which has been given t h e value 70, it IZING EFFICIENCY OF CHARCOALS By LIONAID WICKBNDEN AND J o l ! ~\V. HISSLLR means t h a t 5 g. of t h e charcoal under examination will Received February 18. I916 do the same work a s 7 g. of t h e average charcoal. and The various methods in general use at the present thus possesses a 40 per cent greater efficiency. By using a solution of the strength indicated, t h e time for comparing the decolorizing values of charcoals, possess features which render them, for one difference in color between the solutions forming t h e reason or another, unsatisfactory. In most oil lab- scale is sufficiently marked for comparisons t o be made oratories, direct tests are made with the oil r h i c h without the aid of a colorimeter. I n order, however, is t o be treated. Such tests are satisfactory as far t o make our comparisons easier a n d more exact, we
