an effective against light and oxygen for POLYETHYLENE POLYPROPYLENE POLYVINYL PLASTICS
IVOIDOX\W< I I I I I I I
In low concentrations, retards darkening, cracking, crazing, and formation of brittleness due to oxidation and exposure to sunlight. An effective lubricant in extruding plastics. Increases flex· ibility by internal plasticization.
¥
A food-grade, white, waxy modified fatty acid derivative of a substituted phenol.
Send for sample, literature, prices on your letterhead. INDUSTRIAL DIVISION
G UARDIAN pHEMICAL
^J /CORPORATION
38-15 30TH STREET, LONG ISLAND CITY 1, N.Y.
56
C&EN
SEPT.
18, 1 9 6 1
Virulent Bacteria Form 3-Keto Glycosides Metabolic products differ in virulent and nonvirulent strains of A. tumefociens
140TH
ACS NATIONAL
MEETING
Carbohydrate Chemistry
A disaccharide containing a keto group has been identified as the principal metabolic product o.f a virulent bac terium. The 3-keto glycoside, a-3keto-D-glycopyranosyl-β - D - fructofuranoside, comes from metabolism of Agrobacterium tumcfaciens virulent strains, according to Eugene Grebner, Dr. David Feingold, and Dr. Richard Durbin of the University of Pitts burgh. So far, the 3-keto glycoside has not been found in cultures made with nonvirulent strains of the bacterium. This could signal an unusual metabolic pathway for the virulent strain, which causes crown gall disease in plants, the three scientists believe. Dr. Feingold first suspected a dif ferent metabolic path for the micro organism when one of the products of a sucrose-fed culture of the virulent strain was stained red with urea phos phate spray. As the culture aged, the red-staining material became the major carbohydrate component. The product was identified by first separating it from the culture solution, then isolating it by partition chroma tography at low temperatures with butyl alcohol-ethanol on powdered cellulose. The compound has slightly more chromatographic mobility than sucrose in the usual alcoholic solvents. Also, it forms the same color with o-phenylenediamine as methyl 3-keto-glucopyranoside. Only fructose shows up as an identifiable sugar after hydrolysis with acid or invertase. Absence of the glucose portion points out that it changes during metabolism. This points to a disaccharide that probably contains a 3-keto group. To pin down the structure of the product, the research workers ran a number of other tests. They find that reducing it with sodium borohydride, then hydrolyzing it with acid or inver tase gives 0.1 mole of D-glucose, one mole of D-fructose, and 0.9 mole of Dallose. Also, hydrolyzing the reduc-
SEPARATION. Eugene Grebner (left) and Dr. David Feingold inspect an electrophoresis separation of the allose, glucose, and fructose compounds made by hydrolyzing reduced derivatives of the 3-keto glycoside
tion product with a sucrose-specific enzyme from a hybrid yeast strain gives 0.1 mole of D-glucose and 0.1 mole of D-fructose. Putting these results together en abled the three scientists to piece to gether the structure of the reduced product. First, the yeast enzyme showed sucrose, since the enzyme formed equal amounts of glucose and fructose. This leaves 0.9 mole of al lose and 0.9 mole of fructose as an other disaccharide—a D-allosyl-/?-Dfructofuranose. The only initial product which could yield this combination of disaccharides is a 3-keto glycoside: α-3-keto-D-glucopyranosyl-/?-D-fructofuranoside. Besides showing the possible new metabolic pathway, these 3-keto gly cosides have possibilities for synthetic work. Mr. Grebner says. They might be useful intermediates for making a number of compounds. One already made, the D-allosyl-/?-D-fructofuranoside, should help check effects of con figuration at the 3-gluc:jsyl carbon on sucrore enzymes, he points out.
Lilly Has New Peptide Antibiotic
PIGMENT PROBLEM? PROBLEM? POWDER PROBLEM?
Capromycin is effective against mouse TB; hydrolysis shows make-up 140TH
ACS NATIONAL
MEETING
Biological Chemistry
A research team at Eli Lilly and Co., Indianapolis, Ind., has isolated a new peptide antibiotic and is on the way to determining its structure. Named capromycin, the compound is as effec tive as streptomycin or p-aminosalicylic acid against experimental mouse tuberculosis. A previously unidentified strain of Streptomyces capreolus produces capromycin. The peptide antibi otic was isolated by a series of car bon adsorptions and elutions, fol lowed by fractional precipitation. The antibiotic has a tentative em pirical
formula
of
solving it!
^Γ,-^ΤΗ,^ΟΤ-
N l;J> _ 14 0 9 10, and has four ionizable groups, according to Dr. Earl B. Herr, Jr. The equivalent weight, based on titration, is 740. Dr. Herr and co-workers Michael Haney, Jr., and Gail Pittenger find that hydrolysis of the peptide gives five amino acids. Alanine and serine are two of them. There are also three basic amino acids, two of which are α,β-diaminopropionic acid and βlysine. The third basic amino acid appears to be a new one. The analy sis, chemical properties, and nuclear magnetic resonance data indicate that it may be a-(2-iminohexahydro-4pyrimidyl) glycine. Final proof of this must await synthesis. The Lilly group hasn't yet determined the amino acid sequence of capromycin, but they are working on the problem. The mycobacteria that cause tuber culosis gradually become resistant to streptomycin when they are grown in a medium enriched with streptomycin. But these resistant bacteria, the Eli Lilly scientists say, are still sensitive to capromycin. In a capromycin-enriched medium, the mycobacteria slowly develop a resistance to the new antibiotic. The existence of another weapon to use against the microorganism is important to clinicians. For this rea son, the company plans clinical stud ies of capromycin.
în all modesty, let us say that we are the l a r g ë ^ f i S î f m l ^ ^ ^ ë f W O u r kind in the world. We make colors and pigments of the inorganic type—natural and synthetic—the naturals by processing selected ores and minerals, the synthetics by such chemical processes as precipitation and calcination. Williams customer research and development facilities are the finest, so when you're puzzled over a problem using pigments, extenders, magnetic powders . . . let us know. We'll be glad to put our organization to work for you. Write, stating your problem . . . to Department 4 , C. K. Williams & Co., 640 N. 13th Street, Easton, Pennsylvania. ^^^^[wiLUAMS . BLACKS Pure Black Iron Oxide lampblack BROWNS Pure Β row η Iron Oxide Metallic B r o w n Van Dyke B r o w n GREENS Pure C h r o m i u m Oxide Pure H y d r a t e d C h r o m i u m Oxide
. Τ HE WORLDS BROADEST LIN Ε OF ITS K I N D î ^ ^ ^ B EXTENDER P I G M E N T S Anhydrous C a l c i u m Sulfate Rarytcs Calcium Carbonate, Precipitated Silica Whitmf,
REDS Pure Red Iron Oxide Red Iron Oxide V e n e t i a n Red C u p r o u s Oxide NATURALS Raw a n d B u r n t Sienna Raw a n d Burnt Umber YELLOWS Pure Yellow Iron Oxide Ochers
ι '
MAGNETIC MATERIALS M a g n e t i c Iron Oxide ROUGES Glass P o l i s h i n g Metal Polishing ,
WILLIAMS
•Μϋΐ?ΓοπΒ~~5Γ
C. K. Williams & Co. · E. St. Louis, III. · Easton, Penna. · Emeryville, Calif.
SEPT.
18, 1 9 6 1 C & E N
57
other types of particle movement in the cell, it is necessary to focus the microscope optics on a level where there is only electrophoresis. Earlier methods for measuring mobilities are very time consuming and use solvents such as toluene and benzene as the hydrocarbon medium. Some points favoring the microtechnique: • Use of very small samples. • Direct magnification, observation, and timing of the particles' movement. • Measurement of mobilities in an oil medium. • Very quick measurements.
ADDITION. A special heating stag? added to a standard microscope allows seeing the influence of heat on oil samples, helps studies of oil dispersants
New Test Methods Point to Better Lubes Optical microscopy and electrophoresis yield significant data on additives, allow studying mechanisms of oil dispersants 140TH
ACS
NATIONAL
MEETING
Petroleum Chemistry
An approach to studying the mechanisms of oil dispersants has been developed by J. N. Bowden and F. Dimitroff, U.S. Army Ordnance Fuels and Lubricants Research Laboratory at Southwest Research Institute. The method consists of optical microscopy and electrophoresis techniques. Modern high quality crankcase oils depend on dispersant additives to retain and suspend particles in the oil medium and thus minimize sludge. A better understanding of their basic mechanisms is necessary for future military and civilian demands for highly dispersant lubricants in areas other than the automotive field. The SwRI team has studied two major types of dispersant groups: organometallic and polymeric. The work shows that electrophoresis is significantly related to dispersancy in lubricating oils. The test technique permits rapid, accurate measurements of the electrophoretic mobilities of 58
C&EN
SEPT.
18,
1961
both polymeric and organometallic dispersants. It yields data which make it possible to reconcile some of the apparent differences in the performance mechanisms of the two types of additives. Test Method. A standard microscope ( l O x eyepiece and 10X objective) adapted with a special heating stage permits observation of a sample under close control up to 600° F. The microtechnique for measuring electrophoretic mobilities uses a cell placed on the microscope stage. With it, the movement of particles due to electrophoresis can be observed directly. The special cell has two flat Nichrome electrodes between insulating rubber mats, each with a hole corresponding to a spherical concavity of a microculture slide beneath. In a test, the cell contains microscopically visible sludge particles, and the electrodes have a difference of 400 volts across them. The eyepiece has a scaled reticle that permits measuring the time that it takes for an average size particle to move 0.07 mm. toward one electrode. The electrophoretic mobility is calculated and expressed as square centimeters per volt-second. As there are
Conclusions. The work at the Ordnance F & L lab shows that polymeric dispersants function by adsorption on the surface of particles in oil, thus surrounding them with a molecular film that prevents their agglomeration into large particles. The electrophoretic mobility imparted to sludge particles by the polymeric dispersants indicates this adsorption phenomenon. The adsorption of polymeries on particles is thus similar to the action of organometallics. As the dispersant concentration increases, the stability of a sludge suspension improves (when heat is applied). At the same time, the electrophoretic mobility decreases. The electrophoretic mobility is nil at the maximum effective concentration for a stable sludge suspension. This shows the establishment of an equilibrium between the electrically charged entities in the system. The nature of the oil tested significantly affects the dispersancy characteristics. This is probably a result of the true solubility of the dispersant in the base oil. Based on initial work only, the microscopic and electrophoretic techniques are already effective laboratory tools for studying oil soluble dispersants, according to Dr. Dimitroff. They also suggest several areas for additional work, some of which is under way. For more basic knowledge, a study of the effects of the molecular structure of dispersants on adsorption and solubility in lubricating oils is desirable. One project involves electron microscope studies of dispersants in hydrocarbons. As a practical application, the SwRI team is using electrophoresis and sludge agglomeration techniques for dispersant evaluation through correlative studies with engine tests.
Emulsion Polymerization Turned Inside Out
Two new mass spectrometers
Inverse polymerization method uses hydrophilic monomer plus hydrophobic oil phase 140TH
ACS
NATIONAL
MEETING
Industrial and Engineering Chemistry
Chemists at Dow Chemical have turned emulsion polymerization inside out to come up with a variationinverse emulsion polymerization. The latex that results is made up of submicroscopic spheres of water-swollen hydrophilic polymer in a colloidal suspension in the hydrophobic oil. In emulsion polymerization, a hydrophobic monomer is emulsified in water using an oil-in-water emulsifier, and the polymerization is initiated using a water soluble initiator. Inverse emulsion polymerization, by contrast, uses an emulsion made up of an aqueous solution of hydrophilic monomer in a continuous, hydrophobic oil phase using a water-in-oil emulsifier. Both water soluble and oil soluble initiators are used in this .technique, Dow's Dr. John W. Vanderhoff and coworkers told the Symposium on Polymerization and Polycondensation Processes. Monomers that have been polymerized using the inverse technique include sodium p-styrene sulfonate, sodium vinylbenzylsulfonate, 2-sulfoethyl acrylate, acrylamide, acrylic acid, vinylbenzyltrimethylammonium chloride, and 2-aminoethyl methacrylate hydrochloride. Technical sorbitan monostearate .(Atlas Powder's Span 60) proved to be the best of the water-in-oil emulsifiers tried, according to Dr. Vanderhoff. Benzoyl and lauroyl peroxides are typical of the oil soluble initiators used. In some cases, however, the Dow group used water soluble potassium persulfate, either by itself or mixed with the peroxides. Mechanism Differs. The polymerization mechanism for the inverse technique differs from that for the conventional method, Dr. Vanderhoff says. The micellar theory of emulsion polymerization explains that most of the monomer is contained in the monomer droplets, although some also exists as solute molecules in the water phase and some as solubilized molecules in the emulsifier micelles. Most of the
one for gas and liquid analyses..·
one for gas, liquid and solids analyses On top, C E C ' s 21-130 Laboratory Mass Spectrometer, a mediumpriced instrument designed to m a t c h in its mass range the performance of the largest mass spectrometers. This is the most accurate, versatile and convenient mass spectrometer a t its price . . . mass range from m/e 2 to 230 continuous... stainless steel heated inlet system to 150~C... built-in direct-writing oscillograph. Below, the 21-110 Mass Spectrometer, a materials research instrument. I t is the only commercially available mass spectrometer capable of high resolution analysis of liquids, gases and solids. Project and research directors can count on it to differentiate ion species in any mass range having mass differences as small as one p a r t in 2500. For complete information, call your nearest C E C sales and service office or write for Bulletins C E C 21130-X8 and C E C 21110-X4.
Analytical & Control Division
CONSOLIDATED PASADENA, CALIFORNIA
ELECTRODYNAMICS
· A SUBSIDIARY OF BELL & HOWELL
SEPT. 18, 1961 C & E N
59
WHY SELECT ACE FIBER GLASS SINTERED
FILTERS? Quality
and Greater Abrasion Resistance. Ace filters, the first Ameri-
can made sintered glass filters, feature a glass fiber structure, more abrasion resistant because it is fused together on a larger area. Particles do not detach from the filter body as easily as spherical granules. The shock and chemical attack resistance of glass is unimpaired as the Ace fiber glass sintered filter is made entirely of glass. You are assured of Ace Glass quality: each filter plate is individually tested for porosity and hardness. Selection and Economy. Ace fiber glass sintered filters are economically priced. For instance, the Filter Funnel (Cat. #7305
in the 20 ml.
cap. with 20 mm. disc), shown in photograph above, is listed at $3.20. Ace fiber glass sintered filters have been incorporated into a wide variety of Ace glassware described in our new filterware brochure. Get it for your files! Write Dept. C for your copy of Filterware Brochure No. 6 0 5 0 .
ACE GLASS 60
C&EN
SEPT.
18, 1 9 6 1
emulsifier forms micellar aggregates, but some ions are adsorbed in the oilwater interface, and some emulsifier exists as solute emulsifier in the water phase. Free radicals come from the water phase and migrate to the monomerwater interface. These radicals tend to enter a micelle rather than a monomer droplet, since the surface area of the micelle is large compared to that of the droplets. As polymerization proceeds, the monomer-containing micelle becomes a monomer-swollen polymer particle. The micelles finally disappear after all the micelles have become polymer particles, or have given up their monomer and emulsifier to a radical-containing neighbor. No new particles are formed following the disappearance of the micelles. Those already existing, however, continue to grow until there is no more monomer or free radicals. In contrast to the mechanism for emulsion polymerization, initiation of inverse latex particles doesn't follow the micellar theory. Dr. Vanderhoff says this is shown by the fact that at high emulsifier concentration the number of particles initiated is independent of temperature. The emulsions, he feels, are made up of very fine droplets of aqueous monomer solution which then polymerize to aqueous polymer particles. The kinetics of a polymerization depend on the structure and solubility of the initiator. Unexpectedly, the number of radicals per particle is small for benzoyl peroxide, whereas that for persulfate-initiated polymerizations is normal for an emulsion system. When benzoyl peroxide is used to initiate the polymerization, the initiation is most likely due to benzoyl peroxide which diffuses into the particle and decomposes. Not as Stable. The creamy, rather viscous latexes formed by inverse emulsion polymerization aren't as stable as conventional latexes, Dr. Vanderhoff explains. If left to stand, the particles will settle out in a few hours to a few days, although continuous, gentle agitation will keep the latex in a colloidal state indefinitely. This relative lack of stability is most likely due to the absence of, or difference in character of, the electrostatic forces existing in a conventional latex. In the latter, the electrostatic forces of repulsion are stronger than the London-van der Waal's forces of attraction. These electrostatic forces
corne from emulsifier ions adsorbed on the hydrophobic polymer particle surface. These, together with the counter-ions from the water phase, form the electrical double layer. Thus particles usually repel one another before they are close enough for the London-van der Waal's forces to predominate. This leads to the stability of many conventional latexes.
DESIGN REFINEMENT..
New Cover for Vacuum Cup Electrodes Now, United offers even greater reliability for solution analysis work with the availability of a new Vacuum Cup Electrode Cover designed by Dr. Schmidt, Head Chemical Spectrographic Section; Metal Association, Frankfort/Main, West Germany. Tested in many applications, over a long period of time, this new Vacuum Cup Electrode Cover will eliminate splash due to thermal turbulence of the sample . . . it will prevent the firing of volatile fluids in the reservoir cup . . . and, in all instances, will assure the spectroscopist of a better controlled excitation.
Ginkgo Pollen Forms Tissue Culture 140TH
ACS
NATIONAL
MEETING
Microbial Chemistry
Pollen from the Ginkgo tree can be grown to form a tissue culture, marking another step toward a detailed knowledge of pollen tissue's metabolism. A start toward determining the nutritional requirements for Ginkgo pollen tissue has been made by Dr. Walter Tulecke of Boyce Thompson Institute for Plant Research, Yonkers, N.Y. The tissue was developed from a single pollen cell, grown in 4- to 5gallon glass bottles. The liquid medium contained vitamins, inorganic salts, a growth hormone (naphthaleneacetic acid), sucrose, and two amino acids, glycine and arginine. As the tissue grew over a four-week period, samples of both tissue and medium were analyzed. Results showed that sucrose is rapidly utilized, that citric acid predominates among the organic acids produced, and that the tissue stores large amounts of arginine. The tissue also secretes amino acids into the nutrient medium. Deficiencies in the medium give poor tissue growth; but because pollen cells store many compounds, the deficiencies do not show up immediately. It's possible that similar methods of studying the metabolism of other tissues of higher plants might lead to new methods for producing industrial chemicals. Ginkgo pollen tissue itself is also interesting from a research point of view. It is composed entirely of cells that are haploid—they have only one set of genes, not two, as do cells of most tissues. Tissue of this sort is useful in some genetic studies.
The Cover is expertly machined from Teflon to precisely match the Teflon reservoir cup of Vacuum Cup Electrodes, Nos. 6010 and 6011. A request on your letterhead will bring you free samples and data . . . immediately on receipt.
U N I T E D carbon products co. P.O. BOX 7 4 7
BAY CITY, MICHIGAN
Inquiries are invited regarding the manufacture of your special requirements for organic sulfur compounds in commercial quantities. See our catalog page in Chemical Materials Catalog.
SEPT. 18, 1961 C & E N
61
