Synthesis of SurfaoeAetive Agents HE role of surface-active agents in modern life becomes apTparent from the tabulation of over 280 such products by Van Antwerpen in the January issue of Industrial and Engineering C h i s t r y , pp. 16-22. There is no doubt that the use of ordinary soap as a detergent and wetting agent is being supplanted to an appreciable degree by these new synthetic organic chemicals. These synthetic surface-active agents are in general similar to soap in that they contain a s o l u b i l i i group and a hydrocarbon chain (or ring with a side chain) of variable length. The sohh i l i z ' i group in each case is water-attracting or hydrophilic, whereas the hydrocarbon portion of the molecule is water-repelling or hydrophobic. The combinationof these two properties, in the same molecule, makes a wmpound active a t the interface between two liquids by decting reduction of the surface tension. Langmuir has suggested that, at the interface between two immiscible liquids, the hydrocarbon portion of these surface-active agents becomes oriented toward the hydrophobic media whereas the other portion of the molecule is aligned toward the hydrophilic material. The behavior of any given wmpound will dep a d , accordingly, on the components of the interface. If the interface is made up of two water-repelling or hydiophobic compounds, obviously the directionof orientation is not so readily predictable. It is apparent, therefore, that the properties of a surface-active agent may be varied more or less as desired by changing the waterrepelling properties (or length) of the hydrocarbon residue and/or m o d i i i the water-attracting properties (or nature) of the soluh i l i z ' i group. The extensive list of compounds with surfaceactive properties, previously mentioned, serve as specific examples of ways of effecting these modifications. The nature of the hydrocarbon residue in these surface-active compounds is determined largely by availability. When the hydrocarbon portion of the molecule is aliphatic, the chain is not branched in most cases because of the relative cheapness of the continuous chain compounds. When the hydrophobic portion of the molecule is of the aromatic or substituted aromatic type, the alkyl and/or aryl substitueots on the aromatic nucleus offer a number of possible variations. Some of the more commonly used solubiliz'i or hydrophilic groups are carhoxyl (.COIH), bisulfate [.O.S(- O)r.OH], dihydrogenphosphate [.O.P(+ O)(OH)S], hydroxyl (.OH), and sulfonic acid [.S(- O)r.OH], all of which have a solubilizing effect that is somewhat characteristic of the group. For convenience, some of the more important types of these surface-~ctive agents may be tabulated as: Type
Gcn-ol Pamulo
Nanc a Description Salt of a fatty acid Cn&r-r(.O.SQ.O-+Na)CO~O-+Na Disodium d t of sulfated fattv acid R'CO.O.C&.CHOH.CHI.OH ..... ~ l y e & l ester of n fatty aeid R . C O . 0 . CHz.CHs.SOI.0-+Na.. .. Sodium fatty-neid-ester rulfon*te R . C O . N H C & . C & . S O I . O - + N ~... Sodium fatty-acid-amidesulfonate R,CO.NH,C&.CHI.NR~. Fatty acid smidodialkylsmine R.O.SOI.0-+Na Sodiumalkylsulf~te,where R is large R'KB.O.SOI.O-+Na Sodiumsccondnrydkylsul-
A. 1. R.CO.0-IN*.. 2.
3.
4. 5. 6.
B. 1. 2.
........ .................. .............
3. R'.O.OC.CHI..
I
C.
..................
..................
R'.O.OC.CH.O.SQ.O-+Na.. 1. R . S O I . O - + N ~
2.
a.
....
.................... Ar.SOs.O-+Na. ..................
.................... ......... ..........................
R'.O.OC.CIL
I
R'.O,OC.CH.SOI,O-+Na D. 1. R . N +
In this tabulation the symbol R represents a long hydrocarbon chain of thealiphatic type, Ar signifies an awl or aromatic residue, and R' is a primary or secondary a k y l group of comparatively low molecular weight. Specific examples of each of these types are: A.
1. 2. 3.
O r d i m soap or sodium stearate. C I L . ( C H , ) J ~ . C O . O - + N ~ Tbe sodium salt of the sulfated derivative of rieinoleic acid, C&.(CH~))I.CH(O.SO,.O-+N~) .CH*.HC:CH.(CH,)r.CO.O-+Nn Olyeeml oleate. CHI,(C&)r,HC:CH. (CH~)VCO.O.CHI. CHOH..
The sodium s i l t of the sulfated derivative of dioetyl malate.
C~.(CH~~.CHI.O.OC.CH(O~SQ.O+N~)~CH~.CO.O.CH~. (cHd..cn, Sodium lauryl sulfonnte, C & . ( C H ~ ) I O . C & ~ S O S . O - + N ~ sodium laurylbenrene alfonate, CHI.(CH~)XO.CHI.CI&.SQ.0-+Na Aerosol 0 . T. Dm. &&v.O.OC.CH(SOI.O-+Na).CH,~CO~O.CsHn Laurylpyridininim chloride, CHI. ( C H d a CI&.GHINH+-CI
Of these several types of surface-active agents, probably the most commonly used domestically are of the C. 1 type, to which presumably belong Cue, dreft, drene, Irium, and Teel. Cue is doubtless a salt of an alkyl sulfonic acid, dreft contains sodium lauryl sulfonate as the principal ingredient, drene is the triethanolamine salt of lauryl sulfonic acid suspended in an inert medium. Irium is advertised as the sodium salt of an alkyl sulfanic acid, and T e d is no doubt a salt of an alkyl sulfonic add. -ED. F. DEGERING
Barium for Bearings From the research laboratories of the General Electric X-ray Corporation comes the announcement of the solution of a diffcult lubrication problem. To lubricate a rotor operating in a vacuum in an X-ray tube ails and greases are not permissible because of their high vapor pressures. It was found that when a thin film of metallic barium was applied to the hearing, the speed of the rotor rose to over 3500 R.P.M.. the noise was reduced, and the coasting time was increased from 12 seconds t o eight minutes. -LAURENCES. FOST~R
Toluene from Petroleum The 6rst petroleum toluene refinery has just recently been put in operation in Houston, Texas, by the Shell Oil Company. The new process will help prevent recurrence of the serious bottleneck caused during the World War by limited facilitiesfor recovering toluene from coal tar. The plant a t Houston will produce over 2,000,000gallons annually, from which it is possible to produce about 20,W0,000pounds of TNT.
Thiourea
Thiourea (thiocarbamide) went into commercial production for the 6rst time in the United States in 1940. This compound is used as an intermediate in making thiamine chloride (vitamin B1)and sulfathiazole. 2-sulfadyl-amino-thiazole. one of the newSodium nlkyl rulfon~tc. est additions to the sulfanilamide family of drugs. Other memwhere R is large bers of this family, produced during the last year and undergoing Sodium a w l ssulfonatt Sodium salt of the sulfonie exhaustive tests before being released, are sulfadivine (sulfanilylacid derivative of P diamino-pyrimidine) and sulfaguanidine (sulfadyl-&dine). plkyldicarborylafe The latter has attracted special attention because of its extraAn slkyl pyridinium salt. n h u e R is n long &ordinary value as an intestinal disinfectant. phatie chain (Continued on poge 133.) tate
Sodium salt of the biaulfntc of P dialkyl dic~rboxylate
I.02
mary sodium phosphate and 0.002 M secondary sodium phosphate rather than with water to improve the separation. The adion of the phosphate solution is not TABLE 2 entirely a matter of buffering, for other buffers of the CORBBCTBD RBSULTS same pH do not have the same effect. Adsorption of U". kmwn ? Vidorio BIvr 7 Cryrlol Violet r Auronrins the phosphate undoubtedly plays some role. Numbn Tokc* Pound Erra Taken Fovnd Enor Token Pound E v a The unknowns are prepared and added in ethanolic, rather than aqueous, solution to increase their stability. Auramine is particularly unstable in water. The solutions in ethanol were stored in the dark but subjected frequently to ordinaty daylight for a period of five months without decomposition. The use of ethanol as a solvent requires a rather concentrated solution of unknown lest suffiaent ethanol be introI t may be concluded that the recommended proce- duced with the unknown dye mixture to affect the dure yields results with a relative error of t 13 per chromatogram. cent or better for quantities of dyes over 90 y and a After the apparatus is assembled and the standard maximum absolute error of * 12 y for smaller quanti- solutions prepared, the student can easily run a deties. termination in two three-hour laboratory periods. It remains now to explain several steps in the prow During the 6rst period, the chromatogram must he dednre. veloped, the dyes separated, and the ethanol added "HyBo-Supercel" is added to the adsorbent to in- to each fraction. Otherwise, if the dyes are left in concrease its porosity and thus to decrease the time re- tact with alumina in aqueous medium, excessive decomquired for the determination. position may occur. The second period is then used The chromatogram is developed with 0.002 M pri- for the filtrations and colorimetric determinations.
desorption and decomposition. The corrected results are given in Table 2.
W&d
Bee*c
OH
SYMPOSIUM AT THE ST. LOUIS MEETING OF THE DIVISION OF CHEMICAL EDUCATION
(Continuedfrom Page 102.)
Assimilable Caluum Calcium alpha-hydroxy-isohulyvdte, marke~rd in buvuwd sulution as calcium "borohibate," produced commercially for the fist time by the Amcrican Cyanamid Company, provides calcium in readily assimilable form.
The Platinum Metals Palladium is finding dental use. Alloyed with gold, it is used for inlays and for partial and full dentures. Platinum itself is well established as a basis for dental porcelain work. Palladium is also used in telephone relays. and as a hydrogenation catalyst, especially for organic compounds. Platinum-rhodium alloys are in demand for rayon spinnerettes, and in the form of gauze for ammonia oxidation. I n airplanes, platinum-iridium and platinum-ruthenium are used for magneto points, and may find application in spark plugs. Platinurnclad nickel is being developed for optical frames, but one of the most recent uses of platintub is in the farm of leaf for exterior decoration. because of its resistance to tarnish and atmospheric discoloration. This leaf, also available for outdoor signs and for sculpture, is beaten by machine and by hand to a thicknezs of only one quarter-millionth of no inch
AT THE meeting in St. Louis, April 7 t o 10, the program of the Division of Chemical Education will include a symposium on "Reorganization of the College Chemistry Curriculum." It will deal with the work ordinraiiy covered in the junior and senior years, as follows: Introduction-John C. Bailar, Jr. Courses in Advanced Inorganic Chemistry-P. W. Selwood, Northwestern University Discussion by J. A. Babor. College of the City of New York Courses in the Identification of Organic Substam-R. L. Shriner, University of Illinois Discussion by George H. Coleman, University of Iowa Courses in Physical Chemistry--Frank Havorka, Western Resenre University Discussion by W. Albert Noyes, Jr., University of Rochester Senior Research-John H. Yoe, University of Virginia Discussion by J. L. Riebsomer, DePauw University The success of the similar symposium a t the Detroit nleeung, whichdealt with thecurriculumof thc frst twocollege years, indi- ' cat- the likelihood of a profitable and enthusiastic sessinn.
WHAT'S IN A NAME? Then there is the story of the man with rheumatic pains, which his doctor thought w u l d be relieved by "nitrate ofpotash." Thepatient took the medicine for some time but m s not much benefited. The doctor did not see himfor sotime, until one &y he met him and asked after his health. "Oh, I'm getting toell, doctor,'' m s the reply, "but 'tain't your medicine. I tried thot for quite a while, 'ti1 a neighbor told me of something he took for his rheumatism. Ita very simple thing; Itrieditand it did m e a b t o f good." "Whot is it?" asked the doctor. "Well, I rather btn to tell you. It's so simple you'll laugh at me. It's saltpeter."
