DESTROYING PEROXIDES

8/7/2019 DESTROYING PEROXIDES

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Reprocessing stored ether to very low A. c. H Aperoxide levels can be accomp lished by treating itwith amines or with a variety of inorganic reagents

D E S T R O Y I N G P E R O X I D E S O FI S O P R O P Y L E T H E R

The e xp los ive na tu re o f pe rox ide s o f i sop ropy l e the ran d th e r isk of fa ta l acc id ents hav e led to a con sum erd e m a n d f o r a p r o d u c t w i t h m o r e s t r i n g e n t p e r o x i d el imi t a t io ns . Som e c us tom e rs now spe ci fy a pe rox ide -f re e e the r , o r a n i sop ropy l e the r w i th a pe rox ide c on te n to f no more tha n a f ew pa r t s pe r mi l l i on . B e c a use of t hee x t re me susc e p t ib i l i t y o f i sop ropy l e th e r t o ox ida t io n , i t isof ten d i ff icul t for the producer to meet these new require me n t s . T he p rod uc e r ma y f ind i t ne c e ssa ry to r e p roc e sss to re d e the r w h ic h ha s a c qu i re d some pe rox ide s in o rde rto me e t t h i s more e xa c t ing g ra de .

Pe rox ide s o f i sop ropy l e th e r ha ve a h ighe r bo i l i ngpo in t t ha n the e the r itself, a nd the e the r t he re fo re c a nno tbe safe ly dry-dist i l led unless peroxides a re known to bea b s e n t . T h e t e m p e r a t u r e a n d c o n c e n t r a t i o n a t w h i c he x p l o s i o n b e c o m e s p r o b a b l e h a v e n e v e r b e e n a u t h o r i t a t i ve ly s t a t e d . Eve n a ve ry sma l l a m ou n t of pe ro x ide m a ybe da nge rous , s inc e i t i s c onc e n t ra t e d in the s t i l l sy s t e m.

The ne e d fo r r e p roc e ss ing a l a rge vo lume o f i sop ropy le the r s to re d a t one o f ou r p l a n t s l e d to a l a bo ra to rys tudy to f ind e f fec t ive a nd e c o nom ic me a n s of de s t roy ingpe rox id e s . Pe ro x ide c on te n t of t he s to re d e the r w a sw e l l b e l o w t h e c u s t o m a r y m a x i m u m l i m i t , b u t d i d n o tm e e t t h e n e w r e q u i r e m e n t s . I t w a s h o p e d t h a t p e r ox ide s c ou ld be c onve r t e d to ha rmle ss subs t a nc e s w h i l eus ing a n a mo un t of r e a g e n t sma l l e no ugh to ha v e node le t e r iou s e ffe ct on e the r qua l i t y . Th i s goa l w a s no ta t t a i n e d a n y m a t e r i a l w h i c h c o m p l e t e l y d e s t r o y e dp e r o x i d e s a ls o a p p r e c i a b l y d e g r a d e d t h e e t h e r . S u b se qu e n t r e d i s t i l l a t i on o r de h yd ra t io n is r e qu i re d torestore the e ther to the spec if ica t ions of a re f ined product .

M ate r ia ls tested for the i r e ffec t on perox ides of i sop ro py l e the r i nc lude d se ve ra l a mine s , u se d bo th in un d i lu t e d fo rm a n d a s a qu e ous so lu t ions . Ino rga n icr e a g e n t s p r e v i o u s l y r e c o m m e n d e d i n t h e l i t e r a t u r e w e r ea l so t e s t e d . The se inc lude d so lu t ions o f sod iu m hy d rox ide , sod ium me ta b i su l f i t e , f e r rous su l fa t e , a nds t a nn ous c h lo r ide . In a dd i t ion , so l id s t a nn ous c h lo r id e ,f e r rous su l fa t e , a nd sod ium me ta b i su l f i t e w e re t e s t e d .

R e su l t s o f t he se t e s t s show e d tha t : In a cold washing operation, high concentrations of peroxideswere completely removed by treatment with 25% by weight ofundiluted triethylenetetramine, and reduc ed to very low concentrations by treatment with this amount of undiluted diethylene-triamine and propylenediamine. W he n ether which contained peroxides was refluxed in thepresence of 25% by weight o f undiluted triethylenetetramine and

diethylenetriamine complete removal o f the peroxides occurredwithin one hour. Aqueous 20% solutions of hydroxylamine hydrochloridedestroyed peroxides when u sed in cold washing treatments. Sod ium metabisulfite solution was the most effective of theinorganic reagents tried. This reducing reagent was found toreact quickly with the peroxides in isoprop yl ether in essentiallya stoichiometric manner. Stannous chloride was the only inorganic reagent which waseffective in the solid form.

B e c a use of o the r va r i a b le s t ha t w o u ld be in t ro duc e d , i ti s no t poss ib l e f rom th e l a bo ra to r y e xpe r i e nc e to c hoose asingle "best" reagent , or to g ive spec if ic inst ruc t ions forre m ova l of pe rox ide s by the u se o f t he ino rg a n ic r e d uc in ga ge n t s i n p l a n t - sc a l e ope ra t ions . P l a n t e qu ipm e n t forc onduc t ing the t r e a tme n t w ou ld in f lue nc e the r e su l t s ,a nd th e pe ro x ide c on te n t of t he tw o l iqu id pha se s du r in gt h e m i x i n g o p e r a t i o n .

Fo r ou r pu rpose s , t he be s t sy s t e m w a s c hose n a s c o ld -w a s h ing w i th sod iu m me ta b i su l f i t e so lu t ions . W hi l ede ta i l s o f t he ope ra t ions w e re no t g ive n , i t w a s r e c e n t lyr e p o r t e d b y t h e P r o d u c t i o n D e p a r t m e n t o f t h e C h e m i c a l sD iv i s ion tha t i sop ropy l e the r ha v ing 0 .017 me q . O 2 pe rg ra m of e the r w a s suc c ess fu l ly t r e a t e d w i th 3 .0 %sod iu m me ta b i su l f i t e so lu t ion . A f t e r t r e a tm e n t a n dsubs e que n t r e f in ing , t he pe rox id e c on te n t o f t he e the rw a s a m a x im um o f 0 .0007 me q . O 2 pe r g r a m o f e the r .Sta in less s tee l eq ui pm en t is prefe rred for th is proces s.Effect of Amines on Decomposition of Peroxides

A m i n e s a n d a m i n e - l i k e c o m p o u n d s a r e k n o w n t o b ee f fe c tive a n t io x ida n t s . O n e o f t he se c he m ic a l s , mo r -pho l ine , ha s be e n suc c e ss fu l ly u se d by the C he mic a l sD i v i s io n of U n i o n C a r b i d e C o r p . to p r e v e n t p e r ox ida t ion of f r esh ly d i s t il l e d i sop ropy l e the r . O t he ra m i n e s , fo r e x a m p l e , d i e t h y l e n e t r i a m i n e , t r i e t h y l e n e t e t r a m i n e , a n d t e t r a e t h y l e n e p e n t a m i n e a p p e a r t o b eequal ly e ffec t ive as peroxide inhibi tors for th is e ther {6).

T he de c om pos i t i on o f pe rox ide s by a mine s ha s be e nr e p o r t e d b y a n u m b e r o f i n v e s t ig a t o r s . C a p p a n dH a w k ins (2 ) s tud ie d the r e a c t ion of o rga n ic a mine s w i tha lka ry l hyd rope rox ide s a nd s t a t e d tha t t he se pe rox ide sc ou ld be c onve r t e d smoo th ly in to the c o r re spond inga lc oho l w i th lo ss o f one a tom o f oxyge n by t r e a tme n tw i t h m a n y a m i n e s . O t h e r s ( 7 , IG ) h a v e r e p o r t e d o nthe de c ompos i t i on o f pe rox id e s by a mine s a nd ha v e

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propo se d pa r t i a l a nd t e n ta t ive me c ha n i sm s fo r t here a c t ion . T he u se o f po lya lky le ne po lya min e s a s a c t iva to r s for pe rox ide -c a t a lyz e d po ly me r i z a t ion by de c omp os i t i on o f t he pe ro x ide c a t a ly s t ha s be e n de sc r ib e d . M a n ya min e s w e re e ffe c tive in b r ing in g a b ou t r a p id po lym e r i z a t i o n a t l o w t e m p e r a t u r e (77).Addition of Undiluted Amines

T he e f fe ct o f und i lu t e d a m ine s on de c om pos i t i o n o fthe pe rox ide s w a s f ir s t i nve s t iga t e d . N o ne o f t hea mine s t r i e d in the und i lu t e d s t a t e e f fe c t ive ly de c ompose d the pe rox ide s un le ss a dde d to the e the r i n r e l a t i ve ly l a rge a m ou n t s . Ty p ic a l da t a ob ta ine d fo r a c o ldw a sh ing p roc e ss a re g ive n in Ta b le I . T r i e thy l -e ne te t r a m ine w a s the mos t e ffe c tive of t he ma ny t r i e d( T r i a l 1 7 , T a b l e I ) . T h e p e r o x i d e s w e r e al s o r e m o v e dby re f lux ing the e the r a sho r t p e r iod o f t im e w i th2 5 % by w e igh t o f e i the r d i e thy le ne t r i a m ine o r t r i -e t h y l e n e t e t r a m i n e ( T r i a l s 6 a n d 1 8 , T a b l e I ) . E t h y l -e ne d ia m ine a nd p ropy le ne d ia m ine w e re l ess e ffe ct ivep e r o x i d e d e c o m p o s i t i o n a g e n t s t h a n t h e a m i n e s m e n t ione d a bo ve , bu t r e su l ts of t he s tud ie s i nd ic a t e t ha tthe se a mine s a l so ma y poss ib ly be u se d in the und i lu t e ds t a t e t o r e m ove da ng e rou s a mo un t s of pe rox id e s f romisop ropy l e the r .

T h e a m i n e s , a n d in p a r t i c u l a r p r o p y l e n e d i a m i n e ,a ppe a r t o be so lub le in i sop ropy l e the r t o a n a pp re c i a b lee x te n t , so tha t i t w ou ld be ne c e ssa ry to se pa ra t e t hea mine f rom the i sop ropy l e the r by d i s t i l l a t i on a f t e rt r e a tm e n t . W he n the a min e s a re f ir s t a dd e d to thei sop ropy l e the r , a c loud ine ss a ppe a r s i n t he e the r pha sea nd re ma ins fo r a n hou r o r tw o a f t e r w h ic h i t d i sa ppe a r s .W he n he a te d , t he e the r pha se c l a r i f i e s imme d ia t e ly bu tbe c ome s c loudy a ga in w he n the so lu t ion i s c oo le d .

T h i s p h e n o m e n o n i s p r e s u m a b l y r e l a t e d t o t h e s o l u b i li to f a m ine in the e the r a nd th e ef fe ct o f t e m pe ra t u re on thso lub i l i t y .Effect of Aqueous Amine Solutions

Sinc e a l a rge e xc e ss o f t he pu re a mine s w a s r e qu i re dfor sa t isfac tory d est r uc t i on of the perox ides , the e ffecof aqu eou s solu t io ns was of in te res t . T h e resul ts of c o ld w a sh ing p roc e ss u s ing a que ous so lu t ions o f t ha mine s a re show n in Ta b l e I I . Th e e ffec t o f t e m pe ra tu ron de c ompo s i t i on o f t he pe rox ide s in c on ta c t w i th so lu t iono f a va r i e ty of a min e s is sum ma r iz e d in Ta b le I I IThe da ta g ive n in the se t a b le s a re t yp ic a l da t a t a ke n f roma l a r g e n u m b e r o f e x p e r i m e n t s t h a t w e r e c o n d u c t e d i n ae f fo r t t o de t e rmine the mos t su i t a b le a mine fo r t hp u r p o s e . T h e a m o u n t o f r e a g e n t r e q u i r e d to d e c o m p o sthe pe rox ide s c a n be e s t ima te d f rom the qua n t i t i es h o w n .

W h i l e t he pe rox ide c on te n t o f t he i sop ropy l e the r w aa pp re c i a b ly r e duc e d by c o ld w a sh ing fo r sho r t pe r iodo f t ime w i th m a n y o f t he a qu e ou s a mi ne so lu t ions , on lo n e c o m p l e t e l y d e s t r o y e d t h e p e r o x i d e s h y d r o x y la m ine hyd roc h lo r id e . Su f f ic e n t da t a w e re ob ta ine d tindica te tha t so lu t ions of th is amine a re e ffec t ive over w ide r a n ge o f pe rox ide c onc e n t ra t ion . In a dd i t ion tt he da t a g ive n in Ta b l e I I , i t w i l l be obse rve d f romfu r the r d a t a show n in Ta b l e V tha t c om ple t e de c om pos it i on of pe rox ide s in i sop ropy l e the r c on t a in in g mor e th a n1000 p .p .m . w a s a c c ompl i she d by c o ld w a sh ing volu me s of the e t her for 2 hou rs wi th 1 vo lum e of a 1p e r c e n t s o l u t i o n o f h y d r o x y l a m i n e h y d r o c h l o r i d e .

H y d r a z i n e , l ik e h y d r o x y l a m i n e h y d r o c h l o r i d e , i s s t rong re du c ing a ge n t . T he re a c t ion of t h i s c he m ic aw i th hyd roge n pe rox ide ha s be e n de sc r ibe d (7 ) , a nd i

T A B L E I . E F F E C T O F U N D I L U T E D A M I N E S

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AmineName

B u t y l a m i n e

D i e t h y l e n e t r a m i n e

E t h y l e n e d i a m i n e

M o r p h o l i n eP r o p y l e n e d i a m i n e

T r i e t h y l e n e t e t r a m i n e

%Added"1511025253

1025531025151025

25

TreatmentS haken 15 mi n . ; hea ted 2 h r . , 55 C .S haken 15 min .S haken 15 min . ; hea ted 2 h r . , 55 C .S haken in te rmi t ten t ly , 1 h r .S haken in te rmi t ten t ly , 1 h r .Refluxed 1 hr .S haken 15 mi n . ; qu ie scen t 17 h r .S haken in te rmi t ten t ly 1 h r .S haken in te rmi t ten t ly 1 h r .Refluxed 2 hr .S haken 15 mi n . ; hea ted 2 h r . , 55 C .S haken in te rmi t ten t ly , 1 h r .S haken in te rm i t ten t ly , 1 h r .S haken 15 min . ; hea ted 2 h r . , 55 G .Refluxed, 2 hr .S haken in te rmi t ten t ly , 1 h r .S haken in te rmi t ten t ly 1 h r . ; qu ie scen t 17 h r .Re f luxed , 1 h r .

Peroxiues, Meg. Oi/G. EtherStart

0 . 0 1 20 . 0 3 60 . 0 1 20 . 2 0 00 . 2 0 00 . 2 0 00 . 0 2 10 . 2 0 00 . 2 0 00 . 0 5 80 . 0 1 20 . 2 0 00 . 2 0 00 . 0 1 20 . 0 5 80 . 2 0 00 . 2 0 00 . 2 0 0

En d0 . 0 1 20 . 0 3 30 . 0 0 60 . 0 1 50 . 0 0 3ni l0 . 0 1 00 . 0 2 10 . 0 1 00 . 0 4 80 . 0 0 10 . 0 2 10 . 0 0 10 . 0 0 50 . 0 0 40 . 0 1 8n iln il

" Per cent by weight of pure amine added to the isopropyl ether.

38 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y


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was anticipated that the peroxides of isopropyl etherwould respond to the action of this reducing agent in amanner analogous to its reaction with hydrogen peroxide.In attempts to decompose the peroxides in a low-peroxide ether, dilute aqueous solutions of hydrazinehad n o effect. In fact, in some tests, the pero xidesincreased during treatm ent. H owever, tests using ahigh-peroxide ether showed that very strong solutionsof this reagent appreciably reduced the peroxides.H ydrazine hydrate , a commercial preparat ion of 85 %aqueous hydrazine, when used in excess of the amount ofperoxides present, destroyed all but a very small amountof the perox ides. Violen t effervescence and evolution ofgas occurred, owing to decomposition of both the peroxides and hydr azine. H ydra zine is a very reactivechemical and the hazards of handling this reagent makeit a very unlikely candidate for decomposition of peroxides in ethers.Under conditions in which the peroxidic ether wasrefiuxed in the presence of aqueous 20% amine solutions, the peroxides were completely destroyed whenhydroxylamine hydrochloride and trie thylenetetraminewere used and reduced to low concentrations usingdiethylenetriamine, die thylaminopropylam ine, e thylene-diamine, morpholine, propylenediamine, t r ie thanol-amine, and te traethylenepentamine (Table III) .

From the laboratory studies it appears that reactionof the amines with the peroxides of isopropyl ether varieswith the particular amine used for the purpose, the concentrat ion, and the temper ature . Th e reader who has aspecial interest in this aspect will find much informationon the chemistry involved from the detailed and extensivestudies of H awk ins (7) and Tobolsky (70).

Peroxides of variable compositions form in isopropylether. Some of the peroxides are more easily decomposed than o thers. Some, the cyclic peroxides of di-acetone and triacetone, which are stated to form in isopropyl ether (P), are claimed to be more dangerouslyexplosive tha n others. For this reason , con tinu ed stiudymay be needed to determine whether certain of theamines will be effective deperoxidation agents under allcircumstances.Experience has been that peroxides often form inisopropyl ether in the latter stages of the refining operation. Peroxidation is a "ch ain reaction " and proceedsat a rapid pace. Such being the case, the addition of anamin e in the ether refining process just prior to the finaloperation may well retard or prevent autoxidation forapprec iable lengths of time. Un pub lished lab orato rydata by the author have clearly indicated the benefitsof this procedure on subsequent stability of the isopropylether.

Effect of Inorganic ReagentsBecause ether peroxides are very unstable and are both

oxidizable and reducible, many inorganic reagentshav e been sugg ested for purification of ether s. Fisherand Baxter (4 ) studied the effect on decomposition ofperoxides in ethers and dioxane by sodium hydroxideand reducing agents such as metal oxides, powderedzinc, sodium bisulfite, stannous chloride, and ferroussulfa te . H unter and Down ing (8), and Williams (12),in reviewing suggested methods for purification of peroxidic ethers to render them free from explosive hazard.Th ey m ention the use of such compo unds as powd erediron, mercury, potassium permanganate, aqueous sodiumcarbonate, ferrous sulfate, sodium metabisulfite andTA BLE I I . EFFE C TO F C O LD WA S H IN G W ITH A M I N ESO LU TI O N S

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Amine SolutionB u t y l a m i n eDie thy lene t r iamineD i e t h y l e n e t r i a m i n e "D i p r o p y l e n e t r i a m i n eD i e t h y l a m i n o p r o p y l a m i n eE t h y l e n e d i a m i n eH y d r a z in eH y d r a z i n e h y d r a te " ,0H y d r o x y l a m i n e h y d r o c h l o r id e "H y d r o x y l a m i n e h y d r o c h l o ri d eH y d r o x y l a m i n e h y d r o c h l o r id e *H y d r o x y e t h yl p i p e r a zi n e "M o n o e t h a n o l a m i n eM o r p h o l i n e "A^-Methylmorpholi n e "P ropy lened iamineT r i e t h y l e n e t e t r a m i n e "T r i e t h y l e n e t e t r a m i n eT e t r a e t h y l e n e p e n t a m i n e "T r i e t h a n o l a m i n e

Volume, Ml.Amine,20 %aqueous soln.

252510253025203253020202525202025252525

Ether2525252575256060507515 050255050255025505 0

Peroxides, Meq. O2/G. Ether

Start0 . 0 2 40 . 0 2 40 . 1 0 10 . 0 2 40 . 0 0 40 . 0 2 40 . 2 0 00 . 2 0 00 . 0 1 70 . 0 0 40 . 0 9 70 . 0 2 80 . 0 2 40 . 0 3 70 . 0 3 50 . 0 2 40 . 0 3 70 . 0 2 40 . 0 2 80 . 0 3 6

En dEther

0 . 0 0 90 . 0 0 80 . 0 2 90 . 0 0 80 . 0 0 20 . 0 0 50 . 0 1 40 . 0 0 1n ilni l0 . 0 0 20 . 0 1 10 . 0 0 90 . 0 1 50 . 0 1 30 . 0 0 90 . 0 1 30 . 0 1 00 . 0 0 90 . 0 1 4

Amine0 . 0 0 1N i lN il0 . 0 0 30 . 0 0 10 . 0 0 4

bN ilN ilT r a c eT r a c e0 . 0 0 10 . 0 0 60 . 0 0 1N i lN i lN i l0 . 0 0 1

" After shaking together with the isopropyl ether these amine solutions remained in contact with the ether overnight {about 17 hours) before analysis for peroxcontent. h A heavy white precipitate of hydrazine sulfate formed in the sulfuric acid solution used in the peroxide analysis. ' Eighty-five per cent hydrazine inwater. Strong evolution of gas when shaken with the ether.

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s t a n n o u s c h l o r i d e , a n d r e c o m m e n d s t e a m d i s t i l l a t i o n o fe the r ove r d i lu t e sod ium hyd rox id e so lu t ions a s a safe p r o c e d u r e f or p u r i f i c a ti o n . T h e U n i t e d K i n g d o m A t o m i cE n e r g y A u t h o r i t y r e c e n t l y i n v e s t ig a t e d t h e k n o w nme thods fo r t r e a t ing e thy l e the r c on ta in ing h igh c on cen tra t io ns of pero xide s af te r use in puri f ica t io n of oreso lu t ions , a nd re po r t e d tha t t he be s t me thod w a s tow a s h the e the r w i t h a n a c id s o lu t ion o f f e r rous su l fa t e(3).

A l t h o u g h s o d i u m h y d r o x i d e a n d s o d i u m c a r b o n a t eso lu t ions ha v e be e n sugge s t e d a s e the r pe ro x ide de c ompos i t i on a ge n t s , t he y w e re no t ve ry e f fe c t ive inre m ova l of t he pe rox ide s de ve lope d in i sop ropy l e the run de r t he t e s t c ond i t io ns e mp lo ye d (Tr i a l s 1 , 2 , 3 , a n d4 , T a b l e I V ) .

A mong the mos t e f fe c t ive ino rga n ic r e a ge n t s t r i e d fo rre mova l o f t he pe rox ide s in i sop ropy l e the r w e re sod iumme ta b i su l f i t e , f e r rous su l fat e , a n d s t a nn ous c h lo r i de .A c ompa r i son o f t he e f fe c t o f t he se th re e r e duc ing a ge n t sm a y be obse rve d f rom the da t a of Ta b l e I V .

Th e pe rox ide s o f i sop ropy l e th e r a t e i t he r l ow or h ig hc o n c e n t r a t i o n s w e r e q u i c k l y a n d c o m p l e t e l y r e m o v e dby w a sh ing the e the r w i th c o ld , ve ry d i lu t e a que ousso lu t ions o f sod iu m me ta b i su l f i t e . Th e a m ou n t of b i su l f i t e p re se n t i n t he w a sh w a te r , i t w a s de t e rmine d , ne e don ly be e qu iva le n t i n a moun t o r s l i gh t ly in e xc e ss o f t hea m ou n t o f pe rox id e s c a l c u l a t e d to be p re se n t in t hee t h e r t h a t is b e i n g w a s h e d ( c o m p a r e a m o u n t s o f s o d i u mbisu l fi t e a n d pe rox id e in Tr i a l s 8 a nd 10 , Ta b le IV ) .

T h e e a s e a n d r a p i d i t y b y w h i c h p e r o x i d e s w e r e d e c om pose d in i sop ropy l e the r by u se o f sod ium me ta b i su l f i t e so lu t ion a re i l l u s t r a t e d in the da t a ob ta ine d in thec o r ro s ion t e s t s o f Ta b l e V , w he re the pe rox ide s in a h igh -pe rox ide e the r w e re c omple t e ly de s t roye d by s t i r r i ng 10vo lum e s o f t he e th e r w i th 1 vo lu me of t he a qu e ou s 5 %so lu t ion for 15 min u te s . Som e l a t e r e xpe r ime n t s w e rec o n d u c t e d t o d e t e r m i n e t h e a c t u a l t i m e r e q u i r e d f orde c om pos i t i on o f t he pe rox ide s to t a ke p l a c e by re a c t ionw i th d i lu t e sod iu m me ta b i su l f i t e so lu t ion . In the see xpe r ime n t s [da t a no t i nc lude d in the t a b le s ] 200 ml . o fa 5 % so lu t ion of sod ium me ta b i su l f i t e w a s a dd e d to 800ml . of i sop ropy l e the r c on ta in ing 0 .575 m e q . O 2 pe rg r a m o f e the r i n a 2 - l i te r Py r e x re a c t io n ve sse l e qu ipp e dw i th a n e l e c t r i c s t i r r e r a nd p rov ide d w i th a n a c c e ss fo rsa m pl ing the e the r a nd w a te r pha se s . In th is c a se , t heamount of b isulf i te was only in s l ight excess of thea m ou n t o f e the r pe ro x ide p re se n t . R e su l t s o f t he set e s t s show e d tha t de c ompos i t i on o f t he pe rox ide s w a sv e r y r a p i d . A n a p p r e c i a b l e r is e i n t e m p e r a t u r e o c c u r r e d up on a d d i t i on o f t he b i su lf i t e so lu t ion to thee the r ( a bou t 10 F . ) . N o pe rox ide s w e re found insa mple s o f t he e the r o r w a te r pha se w i thd ra w n a t a ny o fthe t e s t i n t e rva l s dow n to a s l ow a t ime in t e rva l a s 30se c onds . W he n the pe rox ide c on te n t is h igh , c ons ide r a b l e h e a t is e v o l v e d in t h e t r e a t m e n t w i t h s o d i u m m e t a b i su l fi t e a nd the r e a ge n t shou ld be a d de d s low ly a nd w i t hc o o l i n g .

La rg e r qua n t i t i e s o f f e r rous su l fa te a nd s t a n nou sc h lo r ide in the fo rm o f t he i r a que ous so lu t ions a re r e -

T A B L E I I I . E F F E C T O F R E F L U X I N G W I T HA M I N E S O L U T I O N S

Trial1234567891011121314

151617

Amine SolutionB u t y l a m i n eD i e t h y l e n e t r i a m i n eD i p r o p y l e n e t r i a m i n eD i e t h y l a m i n o p r o p y l a m i n eE t h y l e n e d i a m i n eH y d r o x y l a m i n e h y d r o c hl o r i d eH y d r o x y l a m i n e h y d r o c h lo r i d eH y d r o x y e t h y l p i p er a z i n eM o r p h o l i n eiV-Methy lmorpho l ineA"-Aminopropy lmorpho l ineA r-Aminoe thy lp ipe raz ineP r o p y l e n e d i a m i n eT r i e t h a n o l a m i n eT e t r a e t h y l e n e p e n t a m i n eTr ie thy lene te t r amineT r i e t h y l e n e t e t r a m i n eT r i e t h y l e n e t e t r a m i n e

Peroxides, Meq.02/G .

Start0 . 0 3 60 . 0 3 60 . 0 5 80 . 0 0 40 . 0 3 60 . 2 1 00 . 0 0 40 . 0 3 50 . 0 2 40 . 0 5 80 . 0 5 80 . 0 5 80 . 0 3 40 . 0 5 20 . 0 3 50 . 0 3 60 . 1 0 10 . 2 1 0

EtherAfter

Ether0 . 0 0 90 . 0 0 30 . 0 0 40 . 0 0 10 . 0 0 30 . 0 1 0N il0 . 0 0 40 . 0 0 30 . 0 0 80 . 0 0 50 . 0 0 70 . 0 0 10 . 0 0 20 . 0 0 30 . 0 0 2N ilN il

Reflux"Wate

0 . 0 0 1N ilN ilN ilN ilN ilN ilT r a c e0 . 0 0 10 . 0 0 4N ilN il0 . 0 0 10 . 0 0 1N ilN ilN ilN il

" One volume of 20% aqueous amine solution was refluxed for two howith two and one-half volumes of peroxidic isopropyl ether.

qu i re d to r e move a g ive n a moun t o f pe rox ide s in i sop rop y l e the r t ha n a re r e q u i re d to de s t ro y the pe rox ideu s i n g a q u e o u s s o d i u m m e t ab i s u l f i te . E s t i m a t e s m a df rom da ta g ive n in Ta b le IV ind ic a t e t ha t t he se r e a ge n tmu s t be u se d in e xc ess o f a b ou t f ive t ime s the a m ou nof pe rox ide s p re se n t .

I t w i l l be obse rve d tha t t he pe rox ide s o f i sop ropy l e thew e re de s t roye d by sha k ing the e the r w i th s t a nnouc h lo r ide in so l id fo rm. So d iu m me ta b i su l f i t e a nd fe r rousu l fa t e d id no t de c ompose pe rox ide s w he n u se d in thsol id s ta te .

T h e m e c h a n i s m b y w h i c h t h e p e r o x i d e s a r e r e m o v eb y t r e a t m e n t w i t h i n o r g a n i c r e d u c i n g a g e n t s i s s t a t ein i t s s implest form to be tha t of reac t ion of the oxygeo f the pe rox ide w i th the r e duc ing a ge n t , t he r e a ge nbe ing s imu l t a ne ous ly ox id i z e d (3). W he n f re sh lp re pa r e d , a que ous f e r rous su lfa t e so lu t ion is a pa l e g re ec o lo r . A f t e r sha k in g w i th the pe rox id iz e d e the r , ox idat ion of the fe rrous ion soon occurred as indica ted by b ro w n c o lo ra t ion o f t he so lu t ion a nd p re c ip i t a t ion of ine ly d iv ided red fe rr ic hydroxide on the s ides of threa c t io n f lask . A very f ine wh i te pre c ip i ta t e of t in oxid( S n O 2) o r s t a n n i c h y d r o x i d e f o r m e d w h e n t h e s t a n n o uc h lo r id e w a s f ir s t a d de d to the e the r . Th i s p re c ip i t ac o a g u l a t e s t o s o m e e x t e n t w i t h c o n t i n u e d s h a k i nbu t is d i f f icult to rem ov e by f i l t r a t ion .

Fo r r e mova l o f pe rox ide s , one shou ld c ons ide r bo tthe c on c e n t ra t i on of t he r e du c ing so lu t ion , a n d thra t i o o f vo lu me use d to tha t o f t he e the r t ha t i s be in

AUTHOR A. C. Hamstead is a Staff Associate in the Research and Development Department of the Chemicals DivisionUnion Carbide Corp., South Charleston, W . Va.

4 0 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y


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pur i f i e d . In some c a se s i t m a y be a dv a n t a ge ou s to u sea w e a k so lu t ion a n d a l a rg e vo lu me to p rov ide b e t t e rc o n t a c t . I n o t h e r i n s t a n c e s , m o r e c o n c e n t r a t e d s o l u t ions o f t he r e d uc i ng a ge n t ma y be r e q u i r e d to p ro v idem o r e r e d u c i n g ac t i v i t y . I t a p p e a r s t h a t v e r y w e a kso lu t ions of sod i um m e ta b i su l f i t e e f fe c tive ly de s t roy thepe rox ide s , w h i l e s t ronge r so lu t ions o f s t a nn ous c h lo r id ea nd fe r rous su l fa t e a re more e f fe c t ive tha n w e a ke rso lu t ions .

R e s u l t s o f t h e c o m p a r a t i v e d a t a i n T a b l e s I V a n d Vs t rong ly ind ic a t e d tha t t he b i su l f i t e w ou ld be mos te f fe ct ive a n d e c on om ic a l fo r t he pu rp ose . So d iu mme ta b i su l f i t e i s mo re c os t ly tha n th e f e r rous su l fa t e , t hec os t o f t h i s r e a ge n t be ing a pp rox ima te ly $14 pe r1 0 0 p o u n d s a s c o m p a r e d w i t h $ 7 . 0 0 p e r 1 0 0 p o u n d sfo r f e r rous su l fa t e , bu t i t i s i nd ic a t e d tha t on ly a bo u t1Zs a s m uc h b i su lf i t e a s f e r rous su l fa t e a nd s t a nn ousc h lo r ide w ou ld be ne e de d fo r t r e a tme n t o f pe rox id ici sop ropy l e the r . S t a n nou s c h lo r id e i s qu i t e c os t ly inc o m p a r i s o n w i t h t h e o t h e r t w o r e d u c i n g a g e n t s , i t s c o s tb e i n g a b o u t $ 1 2 7 p e r 1 0 0 p o u n d s .

R e s u l t s of t h e e x p e r i m e n t s c o n d u c t e d i n t h e l a b o r a to ry p rov id e a r e a s ona b le ba s i s fo r p l a n t - s c a l e op e ra t io ns .A s ind ic a t e d in the da t a o f Ta b le V , w he re a l a rge vo lumeof i sop ropy l e the r w a s t r e a t e d in c o r ro s ion t e s t s,good suc c e ss shou ld be ob ta ine d by c o ld w a sh ing thee the r i n a mix ing t a nk w i th 3 to 5 % a qu e oussod ium me ta b i su l f i t e so lu t ion u s ing 1 vo lu me o f t heb i su lf i te so lu t ion in 10 vo lum e s o f e the r . T he a m ou n to f sod i um me ta b i s u l f i t e p re se n t i n t he w a sh w a te rshou ld be e qu iva le n t t o o r s l i gh t ly in e xc e ss o f t he e the r -p e r o x i d e p r e s e n t . I n t i m a t e m i x i n g o f t h e e t h e r a n d

b i su l f i t e -w a te r pha se ne e d no t be c on t inue d more tha n af e w m i n u t e s .

I t shou ld be me n t ione d tha t su l fu r d iox ide , a de c om pos i t i on p r od uc t of sod ium me ta b i su l f i t e , i s s l i gh t lyso lub le in i sop ropy l e the r . In the iodo me t r i c me tho d ofa na ly s i s u se d fo r de t e rmin ing the pe rox ide c on te n t o f t hei sop ropy l e the r t h i s c ompound w i l l r e duc e iod ine tha t i sr e l e a se d f rom the po ta ss ium iod ide r e a ge n t by the pe r ox ide s c a us in g low re su l t s . In o rde r t o be c e r t a in ,the re fo re , t ha t a ll o f t he pe rox ide s ha v e be e n re m ove dby t r e a tme n t w i th the b i su l f i t e so lu t ion , t he e the r shou ldb e w a s h e d w i t h d i l u t e s o d i u m h y d r o x i d e s o l u t i o n o rw i th w a te r a lone to r e m ove th i s im pu r i ty be fo re be i nga na lyz e d fo r pe rox ide s .

I f o the r r e duc ing re a ge n t s , f e r rous su l fa t e o r s t a nnousc h lo r ide , a re p re fe r re d fo r some re a son , i t i s i nd ic a t e dtha t r e p ro c e ss ing o f t he e the r c ou ld be c o nd uc te d on ap la n t sc a le a s i nd ic a t e d a b ove fo r t he b i su l f it e t r e a tm e n tw i t h t h e m o d i f i c a t i o n t h a t t h e a m o u n t o f r e d u c i n g a g e n tin the w a sh so lu t ion shou ld be 5 to 10 t ime s th a t o f t hec a l c u l a t e d a m o u n t o f p e r o x i d e s p r e s e n t in t h e e t h e r t h a ti s b e i n g p u r i f i e d . I n t i m a t e m i x i n g of t h e a q u e o u spha se a nd e the r pha se shou ld be c on t inue d in th i s c a sefor a t least 15 minutes, as fa r as i s known.

A s in the c a se o f t he t r e a tme n t s u s ing a mine s , t hep u r i t y o f r e f in e d i s o p r o p y l e t h e r i s a p p r e c i a b l y d e g r a d e db y t r e a t m e n t w i t h t h e i n o r g a n i c r e a g e n t s . T h e l i m i t so f spe ci f ic g ra v i ty , d i s t i l l a t i on r a nge , w a te r c o n te n t , a n da c id i ty , i n some in s t a nc e s , w e r e a ffe c t ed mos t by thet r e a t m e n t s , a n d s u b s e q u e n t r e d i s t i l l a t i o n o r d e h y d r a t i o ni s r e q u i r e d to r e s to re th e e the r t o t h e spe c i f ic a t ions o f ar e f i n e d p r o d u c t .

T A B L E I V . E F F E C T O F A Q U E O U S S O L U T I O N S O F I N O R G A N I C R E A G E N T S

Trial123456789

101112131415161718192021

ReagentName1 0 % S o d i u m h y d r o x i d e2 0 % S o d i u m h y d r o x i d e2 0 % S o d i u m h y d r o x i d e 62 0 % S o d i u m c a r b o n a t e 61 % S od ium me tab isu l f it e3 % S od ium me tab isu l f i t e5 % S od ium me tab isu l f i t e5 % S od ium me tab isu l f i t e5 % S od ium me tab isu l f i t e5 % S od ium me tab isu l f it e5 % Ferrous sulfa te5 % Ferrous sulfa te5 % Ferrous sulfa te5 % Ferrous sulfa te2 0 % Ferrous sulfa te5 % S tannous ch lo r ide5 % S tannous ch lo r ide5 % S tannous ch lo r ide2 0 % S tannous ch lo r ideS o l id s tannous ch lo r ideS o l id s tannous ch lo r ide

Volume, Ml.Reagent10252030101523 . 35

715201631072035101.4 g .2 . 0 g .

Ether505050608075505050505 050505050505050504050

Peroxides, Meq. O2/G. Ether

Start0 . 0 2 30 . 0 2 80 . 1 0 10 . 2 0 00 . 0 1 10 . 2 2 00 . 0 8 10 . 1 5 20 . 3 1 80 . 3 1 80 . 3 1 80 . 3 1 40 . 1 5 20 . 0 2 70 . 0 4 10 . 3 1 40 . 3 1 40 . 3 1 40 . 0 4 10 . 3 3 80 . 3 6 8

After TreatmentEther

0 . 0 0 60 . 0 1 20 . 0 1 70 . 0 3 7N ilN ilN ilN il0 . 0 1 7N il0 . 0 1 70 . 0 0 70 . 0 0 1N i lNil0 . 0 0 90 . 0 0 1N ilN il0 . 0 0 5N il

Water

0 . 0 0 70 . 0 0 20 . 0 1 3N i lN il

0 . 0 0 5N ilCCCC

0 . 1 3 8N ilN ilNil

" Treatment consisted of vigorously shaking the ether an d reagent together in a small bottle for 15 minutes. b Refluxed two hours,iodine from the potassium iodide reagent, interfering with the analysis for peroxides in the wa ter layer.

The ferric ion liberates

V O L . 5 6 N O . 6 J U N E 1 9 6 4 4 1


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T A B L E V . C O R R O S I O N O F M E T A L S

Treatment ConditionsVol . r eagen t , ml .I sop ropy l e the r , vo l . ml .P e rox ides s ta r t , meq . 02 /g . e the rP e rox ides end , meq . Oz/g. e t h e rTim e o f t r ea tm en t , h r .

Corrosion Rate of Metals, Inch/YearMild s tee lC o p p e rA l u m i n u m 3 0 0 3Stainless s teel type 304

Liquid0.6540 . 0 2 60 . 0 3 5N i l

12 01200

Aqueous 5% Sodium Bisulfite

0 . 1 7 9Ni l*2

Vapor0 . 2 8 3 "0 . 1 1 4N i l dN il

12 012000 .17S

Nil"66Liquid0 . 4 0 60 . 0 2 90 . 0 1 9N il

Vapor0 . 0 1 30 . 0 5 40 . 0 1 1N i l

Aqueous 70%HydroxylamineHydrochloride25 080 00 . 0 3 7

Ni l14Liquid Vapor3 .850 0 .6250 . 0 6 4 0 . 1 5 06 . 1 5 0 ' N i lNi l Ni l

" The peroxide content nil after agitating the solution 75 ? Th e peroxide content at the end of 7 hr. was 0.007 meq. 0%/g. ether; nil after agitatinthe solution2 hr. ' Black deposit on metal; pitted. d Shallow pitting. ' Deeply etched; heavy corrosion deposit; solution contaminated with metal salts

Materials of ConstructionC orros ion t e s t s w e re c onduc te d on a f e w o f t he c ommon

ma te r i a l s o f c ons t ruc t ion u s ing one o f t he ino rga n icre a ge n t s t ha t w ou ld mos t l i ke ly be u se d fo r t he pe rox idede s t r uc t io n , sod ium me ta b i su l f i t e , a nd one o f t he a mine s ,h y d r o x y l a m i n e h y d r o c h l o r i d e , a n e f fe c ti v e a g e n t a n dp ro ba b ly the mos t c o r ro s ive of t he a m ine s t r i e d fo r t h i sp u r p o s e .

R e su l t s o f t he se t es t s i nd i c a t e d th a t fo r t he sho r tin t e rva l s of t im e re q u i re d for t he pe ro x ide c onve r s ionus ing sod ium me ta b i su l f i t e so lu t ions , a ny o f t he c o m mo nma te r i a l s of c ons t ruc t io n c ou ld be u se d . Fo r c on t inuous ope ra t ion in th i s se rv i c e o r fo r p ro longe d pe r iodso f t ime , a pp re c i a b l e da m a g e to mi ld s t e e l, c op pe r , o ra l u m i n u m e q u i p m e n t w o u l d b e e x p e c t e d . S t a i nl e s ss te e l t y p e 3 0 4 w a s u n a t t a c k e d d u r i n g t h e l a b o r a t o r yte s t a nd w ou ld be the p re fe r re d ma te r i a l o f c ons t ruc t ionfo r t he b i su l f i t e w a sh ing ope ra t ion .C o r r o s i v e a t t a c k i n t r e a t m e n t s u s i n g a q u e o u s 1 0 %h y d r o x y l a m i n e h y d r o c h l o r i d e s o l u t i o n w o u l d b e t o os e v e re to c o n d u c t i n m i l d s te e l o r a l u m i n u m e q u i p m e n t .C o p p e r w o u l d b e s u i t a b l e f o r o c c a s i o n a l t r e a t m e n t s .S ta in l e ss s t e el t ype 304 w a s no t a t t a c ke d du r in g a nin i t i a l 4 -hou r e xposu re in the r a p id ly a g i t a t e d i sop ropy le t h e r - a m i n e h y d r o c h l o r i d e s o l u t i o n a n d w o u l d b e t h ep r e f e r r e d m a t e r i a l fo r t h e d e p e r o x i d a t i o n t r e a t m e n t su s i n g t h i s r e a g e n t a ls o . T r e a t m e n t o f t h e i s o p r o p y le t h e r w i t h a n y of t h e o t h e r a q u e o u s a m i n e s o l u t io n st r ied could very l ike ly be done sa t isfac tor i ly in milds t ee l or c o p p e r , b u t n o t i n a l u m i n u m . A l u m i n u mis r a p id ly c o r r ode d du r ing in i t i a l e xposu re s in ne a r ly a l ld i lu t e a m ine so lu t ions . D a ta on the c o r ro s ion re s i s t a nc eo f the me ta l by the pe rox ide de c om pos i t i o n r e a ge n t sa r e s u m m a r i z e d i n T a b l e V .Experimental

R e f ine d i sop ropy l e the r me e t ing a l l spe c i f i c a t ionr e q u i r e m e n t s w a s u se d t o p r e p a r e p e r o x i d i z e d e t h e r f orthe inve s t iga t ion .

A u t o x i d a t i o n o f t h e i s o p r o p y l e t h e r d i d n o t p r o c e e dr e a d i l y as a n t i c i p a t e d b y s i m p l e a e r a t i o n . T h e b e s tme thod u se d fo r t h i s pu rpose w a s to r e pa c ka ge the i so p ropy l e the r i n va r ious ly s i z e d , c l e a r g l a ss , sc re w -c a p

bo t t l e s . T he sc re w c a ps w e re no t t i gh te ne d so a s provide access of a i r to the e ther , and to avoid the possib lha z a rd o f e xp lo s ions a r i s ing w h e n the t i gh te ne d c a pw e r e r e m o v e d f r o m c o n c e n t r a t i o n o f t h e p e r o x i da ro un d the c lo su re . T he c on ta ine r s w e re se t a s ide on thl a b o r a t o r y shelf. Pe rox ide s a t va r ious l e ve l s o f c oc e n t r a t i o n d e v e l o p e d i n t h e e t h e r d e p e n d i n g u p o n s i zo f t he c on ta ine r , pos i t i on o f e xposu re w i th r e spe c t l i gh t , a nd t ime o f e xposu re .

T r e a t m e n t o f t h e e t h e r w i t h t h e v a r i o u s p e r o x i dd e c o m p o s i t i o n r e a g e n t s i n c o l d w a s h i n g o p e r a t i o nusua l ly c ons i s t e d in sha k ing a sma l l me a su re d vo lume othe i sop ropy l e the r o f kno w n pe r ox id e c on te n t w i th k n o w n a m o u n t o f t h e r e a g e n t i n s m a l l s c r e w - c a p b o t t l et h e p e r o x i d e c o n t e n t b e i n g d e t e r m i n e d a g a i n a t t h e e no f the e xp e r im e n t . In some t e s ts l a rge r qua n t i t i e s i s o p r o p y l e t h e r a n d r e a g e n t w e r e a g i t a t e d r a p i d l y w i tan e lec t r ic s t i r re r in g lass conta iners of su i table s ize ans a m p l e s of t h e e t h e r a n d w a t e r p h a s e w i t h d r a w n va r ious t ime in t e rva l s fo r pe rox ide a na ly s i s .

T h e p e r o x i d e w a s d e t e r m i n e d b y a d d i t i o n o f p o t a s s i uiod ide r e a ge n t to t he e the r so lu t ions ju s t p re v iousa c id i fi e d w i th d i lu t e su lfu r ic a c id so lu t ion , a nd t i t r a t ioo f t he l i be ra t e d iod ine w i th QA N sod ium th io su l fa t e .Ac k nowle dgm e nt

T h e a u t h o r w i s he s t o t h a n k J . B . J o h n s o n a nR . M . B e rg of t he C he m ic a l s D iv i s ion o f U n ioC a rb ide C orp . fo r t he i r va lua b le a ss i s t a nc e in p re pa rt i o n of t h e m a n u s c r i p t .B I B L I O G R A P H Y( 1 ) A u d r i e t h , L . F . , " T h e C h e m i s t r y o f H y d r a z i n e , " W i l e y , N e w Y o r k , 1 9 5 1 .( 2 ) G a pp , G . W. , H a w k i ns , E . G . G . , J. Chem. Soc. 1 9 5 3 , p . 4 1 0 6 .( 3 ) D uke s , J . A . , " R e m ov a l o f Pe r ox i de s f r om E t h e r , " U nc l a s s i f i e d R e por t D L (I N - 2 0 1 0 , U . K . A t o m i c E n e r g y A u t h o r i t y , 1 9 5 8 .(4) F isher , F. R . , Bax ter , R . A. , Mines Mag., A u g u s t 1 9 4 0 , p . 4 4 7 .( 5 ) H a m s t e a d , A . G . , L e i s , D . G . , V a nD e l i n de r , L . S . , I N D . E N O . J C H E M . 5 3 , N opp . 6 3 A - 6 A ( 1 9 6 1 ) .( 6 ) H a m s t e a d , A . G . , V a n D e l i n d e r , L . S ., J. Chem. and Ene.Oata 5 , N o . 3 , p p . 36 ( 1 9 6 0 ) . S *(!) H a w k i n s , E . G . C . , " O r g a n i c P e r o x i d e s , " p . 1 0 7 , V a n N o s t r a n d , T o r o n t o , 1 9( 8 ) H u n t e r , W . , D o w n i n g , J ., J.S.C.I. 6 8 , p p . 3 6 2 - 4 , D e c . ( 1 9 4 9 ) .( 9 ) R i e c he , A . , Angew. Chem. 7 0 , N o . 9 , 2 5 1 - 6 6 ( 1 9 5 8 ) .( 1 0 ) T o b o l s k y , A r t h u r V . , M e s r o b i a n , R o b e r t B . , " O r g a n i c P e r o x i d e s , " p . 1I n t e r s c i e n c e , N e w Y o r k , 1 9 5 4 .( 11 ) Whi t by , G . S . , it a!., I N D . E N G . C H E M . 4 2 , N o . 3 , p p . 4 4 5 - 5 2 ( 1 9 5 0 ) .( 12 ) W i l l i a m s , E . C . , Chem. Ind. (London), J u l y 17 , 1936 , pp . 5 8 0 - 1 .

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