NEW!
I/EC
REPORTS
Polymers Sewed up Newly found methods to determine tacticity point the w a y to tailor-made polymers I ACTICITY of polymers c a n n o w be
QO* DIHYDROPYRAN (2,
3-dihydro-4H-pyran)
A new development chemical from
The Quaker Oats Company Q O D i h y d r o p y r a n is a c o l o r l e s s , m o b i l e liquid of e t h e r - l i k e o d o r . I t is v e r y r e a c t i v e ; t h e a c t i v i t y is c e n t e r e d a r o u n d t h e double bond.
CHEMICAL
PROPERTIES
Dihydropyran exhibits properties of a vinyl ether. It adds hydrochloric and hydrobromic acids to form the corresponding 2-halotetrahydropyran. Alcohols add readily to the double bond in the presence of acids; thus addition of methanol forms 2-methoxytetrahydropyran, an acetal from which the alcohol may be readily regenerated by hydrolysis. Here, then, is a method of protecting alcohol groups during reactions. Reactions of dihydropyran with water in the presence of acid or an acidic ion exchange resin results in 2-hydroxytetrahydropyran, the cyclic form of (5-hydroxypentanal. Our Bulletin 137 describes many more reactions, and gives references. PHYSICAL·
P R O P E R T I E S (pure compound) Specific G r a v i t y , 20, 4 ° C . 0.927 B o i l i n g Point. ( 7 6 0 m m . ) " C . 84.3 Freezing P o i n t . ° C . -70 Solubility, 25°C. 1.6 g./ 100 g. water g. water 100 g. d i h y d r o p y ran 0.5 W a t e r azeotrope 9.8 % water ( b . 7 1 - 2 ' C . ) Flash P o i n t , T . ( T a g . closed cup) 0 V a p o r Pressure =C. mm. of Hg. 0 34.9 10 57.0 30 148.0 302.0 50 70 600.0
determined. This means empirical concepts are about dead in polymer chemistry a n d the way is clear for a major forward step in t h e science: Catalog t h e basic parameters which predict structure and store these d a t a in data-processing machines or other devices. A p p r o p r i a t e searching will give the information needed to tailorm a k e polymers. For years, macromolecules were m a d e a n d characterized on the basis of end groups, branching, molecular weights, a n d molecular weight dis tribution. But the work of Zieglcr, N a t t a , and others pointed to another factor : stereospecific regulation— how a r e polymer substituents a r ranged? H o w m u c h is isotactic, syndotactic, or heterotactic? These questions called for n e w methods to characterize polymers— methods which deal with details of chain structure. These details a r e i m p o r t a n t , for they influence be havior—for example, melting point, rigidity, strength, a n d resistance t o solvents. And, chain structure d e tails also reveal the shape of m a c r o molecules in t h e crystalline state— whether they a r e plain, zigzag, or hélicoïdal. At the Division of Polymer C h e m istry several of t h e needed methods c a m e to light, a m o n g them : •
Hydrolysis of crystalline acrylic polymers by both alkalies a n d acids. T h e former is d o n e in an aqueous alcoholic m e d i u m in which the hydrolyzate is insoluble; the latter i n a h o m o geneous solution in aqueous acetic acid. T h e m e t h o d is a way to identify t h e different crystalline types of polymers.
•
Nuclear magnetic resonance was used by Minnesota M i n i n g
QO Dihydropyran is available in 55 gallon drum quantities (net weight 375 pounds) f.o.b. Memphis, Tennessee. Write for our Bulletin 137.
The Quaker Oa's Company
The Quaker Oats Company CHEMICALS
%
36 A
ΤΠΤ
DIVISION
337D The Merchandise Mart, Chicago 5 4 , Illinois Room 437D, 120 Wall Street, New York 5, New York Room 537D, 48 5.E. Hawthorne Blvd., P o r t l a n d 1 4 , O r e g o n Circle No. 8 on Readers' Service Card
INDUSTRIAL AND ENGINEERING CHEMISTRY
(Continued on page 38 Λ)
OPERATING MODELS . . .
I/EC
of equipment shown below, will be on display at the Hardinge Exhibit,
a n d M a n u f a c t u r i n g Co. to characterize polymers in solution. T h e high resolution spectra—particularly at high temperatures—often show nearly the resolution of small molecule spectra. F o r e x a m ple, the peaks for polystyrene in c a r b o n tetrachloride a r e not m u c h broader t h a n those of cum e n e . T h e method can be used to study the conformation of polymer chains. Degrees of regularity, block sizes, a n d copolymer conformation can be determined, as can isotactic a n d syndotactic structures.
BOOTH 582 AT THE CHEM SHOW
T h e completely n e w "OVERD R A I N " CLASSIFIER w i t h upwash action, w h i c h prevents slimes from remixing w i t h sands for greatest efficiency in sand washing.
T h e n e w "ELECTRIC EAR"® g r i n d i n g mill feed control with built-in sound rec o r d i n g chart, w h i c h keeps a continuous record of your mill operation around the clock, and increases your grindi n g output 1 0 % t o 20%.
•
S t a n d a r d Oil (Ind.) used differential thermal analysis to study t h e solid-liquid transition of polyolefins a n d copolymers. T h e thermograms obtained give t h e transition temperatures directly. By calibration, heats a n d entropies of fusion were derived from the t h e r m o grams also. T h e n from the heats of fusion, the degree of crystallinity of the polymer can be predicted.
•
M o n s a n t o applied elution fractionation to crystalline a n d a m o r p h o u s polymers. They say it is a reliable w a y to establish molecular weight distributions. Atactic polystyrene can be fractionated by either selective or nonselective deposition. But only polymers with a high diffusion rate can be fractionated by nonselective deposition methods.
•
C h r o m a t o g r a p h y is a quick w a y to get molecular weight distribution d a t a on polyethylene. Tennessee Eastman worked out the route. Polyethylene is fractionated on a column of glass b e a d s ; the lowest t e m p e r a t u r e in the colu m n is above the melting point of polyethylene, so t h a t fractionation takes place by partition of the polymer molecule between two liquid phases in transient equilibrium.
T h e n e w DISC-ROLL MILL with pneumatic grinding roll l o a d i n g and "Gyrotor" Air Classifier w h i c h eliminates overloading and provides the widest possible flexibility in operation. The well-known Hardinge AUTOMATIC BACKWASH SAND FILTER w h i c h , as its name implies, cleans its o w n filter bed automatically without shutd o w n or "change-over."
T h e popular H a r d i n g e "AUTORAISE" THICKENER w h i c h prevents scraper breakage due t o overloads; automatically lifts scrapers upward in an emergency.
HARDINGE
C O M P A N Y , YORK, PENNSYLVANIA
·
I N C O R P O R A T E D
2 4 0 ARCH ST.
·
M a i n Office a n d Works
New York · Toronto · Chicago · Nibbing · Houston · Salt Lake City · San Francisco · Birmingham · Jacksonville Beach Circle Nos. 38-1, 38-2, 38-3, 38-4, 38-5 on Readers' Service Card 38 A
INDUSTRIAL AND ENGINEERING CHEMISTRY
REPORTS
T h e applications are new, n o t the techniques. F o r example, differential thermal analysis has been used
for some time to determine the composition of minerals. B u t application to stereospecific regulation is new a n d the information obtained thus far hints strongly t h a t tailorm a d e stereoregulated polymers are not far away.
AROCLOR SYSTEMS DELIVER S T E A D Y P R O C E S S HEAT T O 6 0 0 ° F and
Sweet Omen
PINPOINT HEAT C O N T R O I . . .
More sucrose-derived products making the grade today; others coming O U G A R is being stirred a r o u n d a lot m o r e things t h a n coffee cups these days. Several sucrose-derived or modified products are in commercial production a n d several more are a b o u t to m a k e the leap. E x a m p l e s : glycerol m a d e t h r o u g h a hydrogenolysis process; piperazine m a d e by treating sugar with a m m o n i a a n d h y d r o g e n ; sucrose fatty acid esters; a n d sucrose phenolic resins—the latest to get the pilot plant onceover. Bright too, are the prospects t h a t other sucrose-spawned materials will bust out of the lab stage into semicommercial status. Examples here include sucrose acetals, sucrose ethers, a n d levulinic acid. And, as research continues in this area of chemistry— called sucrochemistry—the odds improve t h a t lower cost yet better m a terials loom on the horizon. T h e new sucrose phenolic resins are likely candidates. These new resins, developed for the Sugar Research F o u n d a t i o n by Bjorksten Research Labs., h a v e u p to 4 0 % sucrose a n d offer a b o u t a 2 5 % cost a d v a n t a g e over filled phenolic resins available today. R a w material cost for the sugar resins is 10.7 cents per p o u n d ; it's 14.7 cents for the straight phenolformaldehyde resins. A n d large scale use in industry would lead to still lower costs. T h e Valite Division of Valentine Sugar (New Orleans, La.) is m a k i n g the sucrose resin in pilot plant q u a n tities. I n the lab these resins a r e m a d e by dissolving phenol a n d caustic soda in water. Sucrose is added, {Continued on page 41 A)
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t o w i t h i n 2° F . I n d i r e c t h e a t i n g with Aroclor 1248 e n d s processing problems from local h o t s p o t s a n d overheating. U n i t s r a n g e from small, p o r t a b l e electric t y p e s t o large, gasa n d oil-fired h e a t e r s generating u p to 20,000,000 B T U ' s per hour. T y p i c a l u s e s : c o o k i n g of a l k y d resins, dyestuff synthesis a n d o t h e r chemical reactions, deep-fat frying a n d o t h e r food processing, d r y i n g ovens a n d molding e q u i p m e n t .
ECONOMY! Unpressurized s y s t e m s cost less t o install a n d m a i n tain than pressurized systems. Forced circulation of liquid Aroclor requires n o condensers, vaporizers, t r a p s , heavy-walled j a c k e t s or complex feed m e c h a n i s m s . C o m p a c t design saves space. H e a t from a single u n i t can b e supplied for multiple uses a t different t e m p e r a t u r e s . T o t a l efficiency saves processing dollars. FIRE
S A F E T Y !
Even a
blowtorch won't ignite fire-safe Aroclor 1248. A h e a t i n g s y s t e m designed w i t h Aroclor 1248 eliminates t h e h a z a r d of t h e vaporized, flamm a b l e fluid or d a n g e r of direct flame processing. O p e r a t i n g in a closed system vented to the atmosphere, t h e s e h e a t i n g s y s t e m s also eliminate t h e t h r e a t of " l i v e " s t e a m or chemical v a p o r s escaping u n d e r pressure. AROCUM 4 6 firms n o w design or manufacture Aroclor healing systems a n d c o m ponents. Write or use coupon for guide to selecting the best system p——for your application M o n s a n t o Chemical C o m p a n y Organic Chemicals Division Dept. IF-4-B, St. Louis 6 6 , M o .
Please send information booklet on Aroclor 1248 heating systems and guide to heater selection. Name Company A ddress City
_State_
Monsanto WHERE CREATIVE CHEMISTRY WORKS WONDERS FOR YOU
Aroclor: Monsanto T.M., Reg. U.S. Pat. Off.
V O L . 5 1 , N O . 11
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NOVEMBER
1959
39
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