CHEMICALS
W i t h pinic acid a n d o n e equivalent of any alcohol using p-toluenesulfonic acid as catalyst, the p r o d u c t is an easily separated 8 0 : 1 0 : 1 0 ratio mixture of monester, diester, and pinic acid, re spectively. And t h e monester product here is t h e other half ester—the 3-carboxycyciobutaneacetatc form, i n each case, the half esters a r e almost p u r e — one type free of the other, he reports. ^ New Plasticizers, Polymers. Pinic acid is a potentially cheap chemical intermediate. It can he made quite conveniently by ozonolysis of a-pinene. However, it isn't m a d e commercially at present, presumably because n o uses h a v e been found w h i c h cannot b e met by adipic, azelaic, or other dibasic acids, Dr. Hedrick tells C&EN. But this new information should open up some unique rises tor t h e acid, he believes. And, he adds, some of these uses could command a premium price and encour age pinic acid's commercialization. Plasticizers a n d polymers a r e two particularly promising areas singled out by Dr. Hedrick. Pinic acid esters, particularly clioctyl pinate, do a pretty good job as plasticizers for vinyl chlo ride-vinyl a c e t a t e copolymers, he ex plains. But they are not as compatible with vinyl chloride homopolymer. Furthermore, t h e lower esters are too volatile- However, one of the hexyl octyl pinates n o w available via t h e n e w route should turn the trick on both scores, he believes. Pinic acid-ethylen c glycol polymers are unglamorous, glass-like materials and are probably heterogeneous in nature—head-to-head a n d head-to-tail mixtures. But now, by taking a d v a n t a g e of the difference in reactivity b e t w e e n t h e acid's carboxyl groups, it's possible t o make a polymer of either head-to-head or head-to-tail configuration, according to Dr. Hed rick. "And, while w e do not know the characteristics of such polymers, w e guess, and are fairly sure, t h a t they would b e vast improvements over those previously p r e p a r e d / ' he adds. ► N e w Oleic Activity. And in the wake of Emery Industries' announce ment of a seven-fold bike in azelaic and pelargonic acids capacity (C&EN, Sept. 7, 1959, p a g e 2 5 ) conies word of new activity in this area. Headed by Dr. John C . Cowan and Dr. Howard M. Teeter, a U S D A research group at the Agricultural Research Service's North e r n Utilization Research and Develop ment Division h a s come u p with a n e w 100
C&EN
SEPT.
2 8,
1959
"commercially adaptable" ozonization route to aldehydic products of oleic acid, namely pelargonaldehycle and azelaaldehydic acid or their esters or acetals, Dr. Everett H. Pryde told t h e Division of Organic Chemistry. Effi cient, convenient, and economical, t h e new process could spur renewed indus trial interest in these potentially im portant intermediates, he believes. T h e n e w process revolves around t h e use of a reactive common solvent such as methanol or acetic acid in the oxi dation and subsequent reduction of t h e ozonolysis products. Isolated product yields are up in the 87'.; range, says Dr. Pryde. And earhonyl yields before product isolation hover within the 90 to 92'< bracket. While pelargonic and azelaic acids have made dents in some chemical mar kets, there has been little commercial interest in the U. S. in the related al dehydic products. Reason: Industrial production is considered by many to b e impractical. "Now, although our work has been confined to laboratory scale, we think it creates a strong presumption that these aldehyde products have p o tential as industrial chemicals," Dr. Teeter says. ► Versatile Intermediates. From their chemical structure these aldehydic products should be very versatile chem ical intermediates. And azelaaldehydic acid shapes n p as a prime candidate be cause of its difunctional character, he points out. Japanese chemists are nowworking on the preparation of nylon-9 via this acid. Insolubilizing agents for polyvinyl alcohol resins is another pos sibility that USDA investigators will tackle soon. Other potential uses for azelaaldehydic acid or derivatives: polyester resins; frothing agents; modi fiers for textiles, paper, wood, and cel lulose plastics; and polyamide resins other than nylon-9. In addition, Dr. Teeter's group looked at ozonization of soybean oil. T h e product, dubbed "aldehyde oil," consists mainly of glycerol triazelaaldehydate. Its structure is unusual and would b e difficult to get by other proc esses, Dr. Teeter points out. Again, the product may fit into a large number of commercial uses. Items: bacteri cides, nematocides, tanning agents, and the like. However, there are problems to be licked in preparing aldehyde oils by ozonization before commercial pro duction is feasible, he stresses.
Rubeanic Âcid Off and Runnina Mallinckrodt finds this o b scure chemical has long list of possible uses in many fieicis z \ CHKMICAL known since the late 19th century is now making its com mercial debut. Dithiooxamide (rube anic acid) and a series of derivatives are now available in development quan tities from Mallinckrodt Chemical Works. Possible uses: as pigments, herbicides, metal deactivators, and polymer and chemical intermediates. And the series has a wide range of toxicity, signalling possible pharmaco logical uses. T h e series includes dithiooxamide iHoNCSCSXH.j) itself and these six, A\.Y'-disubstituted derivatives: bis( 2-hydroxyethyl ), bis ( earboxymethyl ), dihenzyl, dicyelohexyl, didodecyl, and dimethyl. Although Mallinckrodt chemists have synthesized and evalu ated over 30 dithiooxamides, the seven for commercial development have a representative range of properties, says organic research director George DeLaMater.
These Are Dithiooxamides Now Available This is the
parent S % C—NH> ! C—NH> S
Dithiooxamide (Rubeanic acid)
These Are
Progeny
N,N*-bis(2-hydroxyethyl)dithtooxamide NfN'-bisCcarboxyrrietriyOdithtooxamide N,N'-dibenzyldithiooxamide tyN'-dicycfohexyldithiooxamide NjN'-didodecyîdiîhiooxarnide Ν,Ν'-dimethyIdithiooxarrtide
High on the list of possible applica tions for t h e new class of organics is their use as pigments. Many metal complexes of dithiooxamides have high tinctorial strength, thermal stability, strong ultraviolet light absorption, and insolubility (but easy dispersibility) in water and most organic solvents. Other promising uses determined by Mallinckrodt and other scientists: • As metal séquestrants (metal de activators iv petroleum products, for example ). • For various duplicating processes, because they have intense ink-like colors a n d form many complexes rapidly. T h e compounds can b e adapted to processes similar to the spirit (Ditto) process a n d to thermal and electrochemical reproduction sys tems. • As vulcanization accelerators; they cause less scorching than other accel erators used to vulcanize ehloroprene's homo or copolymers. • As reagents to analyze for metal traces. Properties that bode well for applica tion in biological systems include in hibiting grass seed germination, thus slowing the growth of various weeds and grasses. Other research shows they have defoliant properties. Some d e rivatives also appear active as bird a n d rodent repellants, says Mallinckrodt. Possible pharmaceutical applications are suggested by t h e bis(carboxymethyl) derivative's diuretic activity, and several of the dithiooxamides in hibit bacterial growth ► Minor Uses 'Til N o w . The only use for dithiooxaniide until now has been as an analytical reagent for d e tecting some metals like copper, co balt, and nickel. Its synthesis was fairly difficult, too, says Mallinckrodt, a fact which discouraged any extensive applications research. The St. Louis firm b e c a m e interested in the compound in 1951 when it received an inquiry about it. Mallinc krodt chemists synthesized some dithiooxamide via the accepted method based on copper sulfate, potassium cyanide, and hydrogen sulfide. The technique was far from satis factory, says Dr. DeLaMater, and a new synthesis was developed a n d pat ented ( U . S. Patent 2,732,401). T h e patented process, n o w expanded to pilot plant scale, combines hydrogen
cyanide and chlorine in the vapor phase, then reacts the condensate with sodium sulf hydrate. Dithiooxaniide precipitates as a bright orange solid. T h e starting materials, notes Mallinc krodt, are low-cost and plentiful. De velopmental price for dithiooxaniide is $4.50 a pound. Quality is identical with what was formerly reagent grade selling for $32 a pound. Develop mental prices for the derivatives range u p to $6.00 a pound. According to research chemist Richard X. Hurd, dithiooxamides are in some ways like thioamides. But, h e explains, there are big differences in chemical a n d physical properties b e tween the two because of the two con jugated functional groups. Key to d i thiooxamide's apparent versatility is how easily it reacts with amines. Mallinckrodt is also optimistic about the various dithiooxamides' promise as organic intermediates. The compounds can b e used to synthesize many fiveand six-membered heterocyclic prod ucts, such as bis( A--2-imidazolinyl), bitriazine, and dithiazoles. Their d i functional nature permits polymer formation. Examples: polymerization of a,
