Hydrogen, Deuterium, Water

SECTION 1

Hydrogen, Deuterium, Water

M. BAUDLER

Hydroge n

C o m m e r c i a l h y d r o g e n , a v a i l a b l e in s t e e l c y l i n d e r s , i s p r o d u c e d e i t h e r b y e l e c t r o l y s i s o r by t h e w a t e r shift r e a c t i o n f r o m w a t e r g a s .

E l e c t r o l y t i c h y d r o g e n c o n t a i n s 9 9 . 7 - 9 9 . 8 % H³. The o n l y i m - p u r i t y i s a i r , with t h e oxygen a m o u n t i n g to l e s s t h a n 0 . 1 % . T h i s c o m m e r c i a l h y d r o g e n m a y be t r e a t e d e i t h e r by p a s s a g e t h r o u g h a c o m b u s t i o n t u b e filled with r e d u c e d CuO w i r e at 400°C, o r by p a s s a g e t h r o u g h t h e " a c t i v e c o p p e r t o w e r " of M e y e r and Ronge

( s e e s e c t i o n on N i t r o g e n ) , followed by d r y i n g with C a C l² o r P s 0⁵. T h e g a s o b t a i n e d by e i t h e r of t h e s e m e t h o d s m a y b e u s e d for m o s t l a b o r a t o r y a p p l i c a t i o n s , s i n c e i t s v e r y s m a l l N² c o n t e n t (about 0.2%) i s u s u a l l y not h a r m f u l . If c o m m e r c i a l e l e c t r o l y t i c h y d r o g e n i s u n a v a i l a b l e , it m a y b e p r e p a r e d in t h e a p p a r a t u s d e s c r i b e d in t h e s e c t i o n on N i t r o g e n (the p o l a r i t y i s r e v e r s e d , c o m p a r e d to oxygen p r e p a r a t i o n ! ) .

On t h e o t h e r hand, c o m m e r c i a l h y d r o g e n p r o d u c e d f r o m w a t e r g a s i s c o n t a m i n a t e d with c o n s i d e r a b l e a m o u n t s of CO, C O^s, 0² a n d N^s, a n d s o m e t i m e s a l s o w i t h A s H³ a n d F e ( C O )^B. T h e C O^s m a y b e r e m o v e d by a b s o r p t i o n w i t h KOH o r s o d a l i m e ; t h e A s H³ i s t a k e n u p by a fully s a t u r a t e d KMnO ⁴ s o l u t i o n ( c o n t a i n i n g s o l i d K M n 0⁴) . T h e O^s i s s e p a r a t e d out e i t h e r by p a s s a g e o v e r h e a t e d c o p p e r w i r e o r o v e r r e d - h o t P t - a s b e s t o s ( p r e p a r e d a c c o r d i n g to t h e d i r e c t i o n s g i v e n in t h e s e c t i o n on P l a t i n u m M e t a l s ) . T h e l a t t e r p r o c e d u r e a l s o r e s u l t s in t h e r m a l d e c o m p o s i t i o n of t h e Fe(CO)s, T h e r e m o v a l of CO i s m o r e difficult, s i n c e n e i t h e r a b s o r p t i o n in a c i d o r a m m o n i a c a l CuCl s o l u t i o n n o r o x i d a t i o n with HgO (or H I 0³) i s q u a n t i t a t i v e . T h e m o s t r e l i a b l e m e t h o d of r e m o v i n g CO i s f r e e z i n g out at t h e t e m p e r a t u r e of liquid n i t r o g e n . In any c a s e , p u r e H⁹ i s b e s t p r e p a r e d f r o m e l e c t r o l y t i c h y d r o g e n .

V e r y p u r e , c o m p l e t e l y a i r - f r e e h y d r o g e n m a y b e p r e p a r e d b y any of t h e following m e t h o d s .

1 1 1

I. HEATING OF PALLADIUM SPONGE

P a l l a d i u m s p o n g e , p r e p a r e d by t h e r e d u c t i o n of P d C l^a s o l u t i o n (see s e c t i o n on P l a t i n u m M e t a l s ) , i s c a r e f u l l y w a s h e d with hot w a t e r , d r i e d and well c a l c i n e d b y h e a t i n g with a b u r n e r . The hot p r o d u c t i s c h a r g e d into a p r e h e a t e d c o m b u s t i o n t u b e (provided w i t h a m a n o m e t e r s e a l e d to o n e end) and a l l o w e d to cool slowly in v a c u u m . When t h e s p o n g e r e a c h e s r o o m t e m p e r a t u r e , a c a r e f u l l y p r e p u r i f i e d and p r e d r i e d H² s t r e a m i s a d m i t t e d into the t u b e and is to a l a r g e e x t e n t a b s o r b e d b y t h e P d . T h e a b s o r p t i o n p r o d u c e s a s l i g h t glowing of t h e s p o n g e . W h e n t h e s p o n g e i s t h e n h e a t e d t o about 200°C, p u r e H² is l i b e r a t e d . A s t e a d y s t r e a m of t h e g a s m a y b e o b t a i n e d with t h e aid of a s m a l l p u m p . In t h i s way, 100 m l . (STP) of Η ² m a y be o b t a i n e d p e r g r a m of p a l l a d i u m .

T h i s m e t h o d i s e s p e c i a l l y useful in t h e p r e p a r a t i o n of s m a l l q u a n t i t i e s of v e r y p u r e h y d r o g e n . E . von A n g e r e r ( T e c h n i s c h e K u n s t g r i f f e bei p h y s i k a l i s c h e n U n t e r s u c h u n g e n [ i n d u s t r i a l T e c h ­ n i q u e s Applied to P h y s i c a l E x p e r i m e n t s ] 6th e d . , B r a u n s c h w e i g , p . 92) s h o w s an a p p a r a t u s c a p a b l e of c o n t i n u o u s p r o d u c t i o n of

100 m l . of p u r e Η 2 p e r h o u r . It o p e r a t e s on the p r i n c i p l e of h y d r o g e n diffusion t h r o u g h e l e c t r i c a l l y h e a t e d P d t u b e s .

II. DIFFUSION THROUGH NICKEL

C o m m e r c i a l h y d r o g e n m a y a l s o b e f u r t h e r p u r i f i e d by diffusion t h r o u g h n i c k e l . T h i s m a y b e a c c o m p l i s h e d in t h e a p p a r a t u s shown in F i g . 8 7 , w h i c h y i e l d s a s t e a d y s t r e a m of v e r y p u r e g a s at a t m o s p h e r i c p r e s s u r e .

The b a s i c c o m p o n e n t i s a p u r e n i c k e l , p r e c i s i o n g r o u n d , s e a m ­ l e s s tube ( d i a m e t e r 2 m m . , length 5 m . , wall t h i c k n e s s 0.1 m m . ) s o l d e r e d s h u t at one end. F i v e s u c h t u b e s a r e n e e d e d . E a c h i s c o i l e d into a h e l i x , t h e h e l i c e s a r e i n t e r t w i n e d , and t h e open end of e a c h t u b e i s s o l d e r e d to a b r a s s h e a d e r , a s s h o w n . The h e a d e r i s p r o v i d e d with a s t a n d a r d t a p e r e d m a l e joint n. F o r e a s e of h a n d l i n g , t h e t u b e s a r e h e a t e d in a H^s s t r e a m at 1000°C for two h o u r s , after which t h e y m a y e a s i l y b e b e n t by h a n d . T h e h e l i x a s s e m b l y i s i n s e r t e d into a q u a r t z r e a c t o r t u b e 1 m . long and 35 m m . in d i a m e t e r . T h e front and b a c k h e a d e r s a r e c e m e n t e d to t h e q u a r t z t u b e with p i c e i n , a s shown. T h e b a c k h e a d e r i s p r o ­ vided with a n e e d l e valve v, which s e r v e s for fine c o n t r o l of p r e s ­ s u r e in the tube and t h r o u g h which the g a s e o u s i m p u r i t i e s , which a r e c o n t a i n e d in t h e h y d r o g e n and which a c c u m u l a t e in t h e r e a c t o r , m a y b e r e l e a s e d and s u b s e q u e n t l y b u r n e d . The front h e a d e r h a s a c o n n e c t i o n for a m e r c u r y m a n o m e t e r . Only t h e m i d d l e p a r t of t h e q u a r t z r e a c t o r is e l e c t r i c a l l y h e a t e d . T h u s , t h e s o l d e r e d p o i n t s of the n i c k e l t u b e s r e m a i n in t h e c o o l e r s e c t i o n s of t h e a p p a r a t u s .

I . H Y D R O G E N , D E U T E R I U M , W A T E R

F i g . 87. P u r i f i c a t i o n of h y d r o g e n by diffusion t h r o u g h n i c k e l : υ i s a n e e d l e v a l v e for fine c o n t r o l of p r e s s u r e

in t h e a p p a r a t u s .

Depending on t h e o p e r a t i n g c o n d i t i o n s , t h e a p p a r a t u s i s c a p a b l e of d e l i v e r i n g t h e following q u a n t i t i e s of h y d r o g e n :

° c 15 20 25 30 m m . Hg 750 20 27 34 41

815 27 36 43 52 > m l . / m i n . 860 34 45 55 68 > m l . / m i n . 900 41 54 68 84

T h e g a s output i s p r o p o r t i o n a l to t h e p r e s s u r e in t h e r e a c t o r but d o e s not v a r y l i n e a r l y with t e m p e r a t u r e . By v a r y i n g t h e p r e s ­ s u r e , any d e s i r e d g a s output c a n b e o b t a i n e d a l m o s t i n s t a n t a n e o u s l y . P r o v i d e d t h e feed g a s c y l i n d e r h a s a good r e g u l a t o r , t h e r e a c t o r will g i v e t r o u b l e - f r e e o p e r a t i o n for about 250 h o u r s . H o w e v e r , it m u s t b e t e s t e d for l e a k s b e f o r e e a c h r u n .

III. DECOMPOSITION OF U H3

2 UH³ = 2 U + 3 H²

482.19 476.14 6.05

T h i s p r o c e d u r e p e r m i t s t h e p r o d u c t i o n of v e r y p u r e h y d r o g e n f r e e of n o b l e g a s e s . T h e g a s m a y b e o b t a i n e d in any d e s i r e d a m o u n t and at any t i m e f r o m p r e v i o u s l y m a d e UH³.

The U H³ m a y be p r e p a r e d in the a p p a r a t u s shown in F i g . 88.

C o m m e r c i a l e l e c t r o l y t i c h y d r o g e n (from a c y l i n d e r ) i s p r e p u r i f i e d by p a s s a g e o v e r c o p p e r s h a v i n g s in t u b e b at 650-700°C and d r y i n g with a n h y d r o u s M g ( C 1 0⁴)² in t u b e o . The g a s m a y b e f u r t h e r p u r i ­ fied at d by p a s s a g e t h r o u g h p u l v e r i z e d u r a n i u m at 700-750°C.

1 13

T h i s p r e p u r i f i e d h y d r o g e n m a y t h e n b e c o n v e r t e d to U H³ in t h e t w o - n e c k flask / , which i s half filled with u r a n i u m t u r n i n g s . T h e s e t u r n i n g s m u s t a l s o be p r e p u r i f i e d by t r e a t m e n t with dilute H N 0³ (to r e m o v e t h e oxide f i l m ) , w a s h i n g and d r y i n g . F l a s k / i s h e a t e d e i t h e r with a n i t r a t e - n i t r i t e s a l t b a t h o r an e l e c t r i c f u r n a c e . T h e t e m p e r a t u r e in t h e flask is 250°C. Two w a s h b o t t l e s , one e m p t y and one filled with c o n c e n t r a t e d H ^ > 0⁴, a r e a t t a c h e d to flask / .

F i g . 8 8 . P r e p a r a t i o n of u r a n i u m h y d r i d e and p u r i f i c a ­ tion of h y d r o g e n , b) t u b e filled w i t h c o p p e r s h a v i n g s ; c) t u b e filled with M g ( C 1 0⁴)³; d) t u b e c o n t a i n i n g u r a n i u m p o w d e r s u p p o r t e d and c o v e r e d by g l a s s wool p l u g s e and e' \ f) f l a s k w i t h u r a n i u m t u r n i n g s ; g) h e a t ­

ing b a t h ; s^{l 9} s²) g r o u n d g l a s s j o i n t s .

The a p p a r a t u s m u s t be t h o r o u g h l y p u r g e d with h y d r o g e n p r i o r to t h e r u n , i . e . , p r i o r to h e a t i n g δ, d a n d / . T h e r e a c t i o n is c o m ­ p l e t e d when t h e H²S 0⁴ in t h e r i s e r of t h e l a s t w a s h b o t t l e i s no l o n g e r p u l l e d u p w a r d by s u c t i o n upon i n t e r r u p t i o n of t h e H² s t r e a m .

T h e U H³ p r o d u c t is a b r o w n - b l a c k , s p o n t a n e o u s l y igniting p o w d e r . V e r y p u r e h y d r o g e n m a y be l i b e r a t e d f r o m it by h e a t i n g , p o s s i b l y at r e d u c e d p r e s s u r e , to 400°C (or t o a s o m e w h a t l o w e r t e m p e r a ­ t u r e ) . T h e u r a n i u m p o w d e r r e s i d u e r e m a i n i n g a f t e r t h e d e c o m ­ p o s i t i o n r e a c t s v i g o r o u s l y with H² at r o o m t e m p e r a t u r e . The r e a c t i o n is s t i l l quite v i g o r o u s at — 80°C and c e a s e s only a t - 2 0 0 ° C .

IV. DECOMPOSITION OF TITANIUM HYDRIDE

T i t a n i u m h y d r i d e i s well s u i t e d for the p r o d u c t i o n of l a r g e r q u a n t i t i e s of v e r y p u r e h y d r o g e n . It h a s a r e l a t i v e l y low d e c o m ­ p o s i t i o n t e m p e r a t u r e (400-900 C), a r e l a t i v e l y high h y d r o g e n c o n ­ t e n t , and i s e a s i l y r e g e n e r a t e d . A s i d e f r o m t h i s , t i t a n i u m oxide and n i t r i d e a r e c o m p l e t e l y s t a b l e at t h e r e q u i r e d d e c o m p o s i t i o n

I . H Y D R O G E N , D E U T E R I U M , W A T E R 1 1 5

t e m p e r a t u r e s . T h e d e c o m p o s i t i o n is e n d o t h e r m i c . T h u s , t h e e v o l u ­ t i o n of g a s c e a s e s w h e n e v e r t h e flow of h e a t i s r e d u c e d , a n d a c o n ­ t i n u o u s , w e l l - c o n t r o l l e d g a s s t r e a m i s o b t a i n e d . It i s a d v i s a b l e to u s e t h e a p p a r a t u s shown in F i g . 89, s o t h a t t h e v e r y p u r e Η^s p r o d u c t m a y b e i m m e d i a t e l y u s e d in h y d r o g e n a t i o n r e a c t i o n s , which m a y be c o n d u c t e d in t h e s p a c e p r o v i d e d at g.

impure H ,

=dp—w—*p I I

r e II £ ^

F i g . 89. P r e p a r a t i o n of v e r y p u r e h y d r o g e n f r o m t i t a n i u m h y d r i d e , a) q u a r t z r e a c t o r t u b e ; b) m o l y b d e n u m b o a t c o n ­ t a i n i n g Ti; o) h e a t i n g winding; d) r a d i a t i o n s h i e l d ; e) r a d i a ­ t i o n s h i e l d s for p r o t e c t i o n of s t o p p e r s ; f) g l a s s wool; g) a p p a r a t u s for c o n d u c t i n g r e a c t i o n s with the v e r y p u r e h y d r o g e n p r o d u c t ; t h e t u b e c o n t a i n s a b o a t f o r t h e r e a c t a n t s and i s s u r r o u n d e d by an e l e c t r i c f u r n a c e . T h i s p a r t m a y be o m i t t e d if the h y d r o g e n p r o d u c t i s to be u s e d e l s e w h e r e ;

m) p r e s s u r e - s e n s i n g s w i t c h ; r ) r e l a y .

A q u a r t z r e a c t o r tube a (O.D. 34 m m . , I.D. 30 m m . , o v e r - a l l length 1500 m m . ) i s wound o v e r a length of 650 m m . with a h e a t i n g c o i l c, which i s c e m e n t e d to t h e t u b e with a t h i n q u a r t z - w a t e r g l a s s s l u r r y . M o l y b d e n u m b o a t b i s p l a c e d in t h e h e a t e d z o n e . T h e r a d i a ­ t i o n s h i e l d d r e t a r d s h e a t l o s s to t h e o u t s i d e . Switch m c o n t r o l s t h e h e a t input to t h e winding, s e n s i n g t h e p r e s s u r e d e v e l o p e d b y t h e h y d r o g e n p r o d u c t s t r e a m .

T h e t i t a n i u m h y d r i d e i s p r e p a r e d a s f o l l o w s : c o m m e r c i a l t i t a n i u m s p o n g e of u s u a l p u r i t y and m e d i u m g r a i n s i z e i s p l a c e d in t h e m o l y b d e n u m boat and d r i e d in a s t r e a m of c o m m e r c i a l h y ­ d r o g e n at 400°C. T h i s s t e p m a y s o m e t i m e s b e o m i t t e d . Following t h i s , t h e t e m p e r a t u r e i s r a i s e d to 700°C. The m a t e r i a l i s t h e n h e a t e d for 30 m i n u t e s while m a i n t a i n i n g t h e g a s flow. T h e n , after t h o r o u g h e v a c u a t i o n of t h e a p p a r a t u s , t h e p r o d u c t ( t i t a n i u m h y d r i d e ) is h e a t e d

until a p r e s s u r e of 0.1 a t m . g a u g e is r e g i s t e r e d on s w i t c h m, at w h i c h p o i n t t h e c u r r e n t i s s h u t off. The p r e s s u r e d e c r e a s e s due to the r a p i d d r o p in t e m p e r a t u r e and c o n s e q u e n t g a s v o l u m e c o n ­ t r a c t i o n ( a n d / o r u s e of t h e g a s for h y d r o g e n a t i o n at g). When t h e c o n t r o l p o i n t p r e s s u r e is r e a c h e d , the c u r r e n t is a g a i n s w i t c h e d on. D e s p i t e t h i s s i m p l e "on-off" c o n t r o l , p r e s s u r e f l u c t u a t i o n s a r e s m a l l .

After t h e d e s i r e d a m o u n t of h y d r o g e n h a s b e e n l i b e r a t e d , t h e t i t a n i u m h y d r i d e m a y be r e g e n e r a t e d by h e a t i n g in c o m m e r c i a l h y d r o g e n and s u b s e q u e n t c o o l i n g . A c h a r g e of 500 g. of t i t a n i u m s p o n g e w i l l l i b e r a t e 100 l i t e r s of p u r e H³ p e r r u n .

V. ELECTROLYSIS IN THE ABSENCE OF AIR

An a p p a r a t u s for e l e c t r o l y t i c p r e p a r a t i o n of H²o r O^s (depending on p o l a r i t y ) in c o m p l e t e a b s e n c e of a i r is d e s c r i b e d in t h e s e c t i o n on N i t r o g e n . The p r o d u c t g a s c o n t a i n s l e s s t h a n 4 · 1 0 "⁶% a i r .

PROPERTIES:

F o r m u l a weight 2.016. C o l o r l e s s , o d o r l e s s , t a s t e l e s s g a s . Its r e d u c i n g a c t i o n i s e s p e c i a l l y a p p a r e n t at high t e m p e r a t u r e s . F o r t h i s r e a s o n , hot H² s h o u l d not be p a s s e d t h r o u g h c o n c e n t r a t e d H²S 0⁴, s i n c e it t h e n b e c o m e s e a s i l y c o n t a m i n a t e d by S 0². M . p . - 2 5 9 . 2 ° C , b . p . - 2 5 2 . 8 ° C ; t^{c r} - 2 3 9 . 9 ° C , p^{c r} 12.8 a t m . g a u g e ; d (liquid) 0.070; weight of 1 l i t e r H² at S T P = 0.08987 g.

Solubility in w a t e r at 760 m m . : 0.021 v o l . / v o l . at 0°C, 0.018 v o l . / v o l . at 20°C, 0.016 v o l . / v o l . at 100°C. Solubility in o t h e r liquids is a l s o v e r y s m a l l .

REFERENCES:

A. K l e m e n c . Die B e h a n d l u n g und R e i n d a r s t e l l u n g v o n G a s e n [ T r e a t ­ m e n t and P u r i f i c a t i o n of G a s e s ] , L e i p z i g , 1938, p . 9 7 .

I. L . M o s e r . Die R e i n d a r s t e l l u n g von G a s e n [ P u r i f i c a t i o n of G a s e s ] , S t u t t g a r t , 1920, p . 37.

II. R. S c h a f e r and W. K l e m m . J . p r a k t . C h e m . (4) 5, 233 (1958);

J . L . Snoek and E. J . H a e s . Appl. Sci. R e s . A 2, 326 (1950);

s e e a l s o : E. R. H a r r i s o n and L . C. W. H o b b i s . R e v . Sci.

I n s t r u m e n t s 26, 305 (1955).

III. F . H. Spedding, A. S. Newton, J . C. Warf, O. J o h n s o n , R. W.

Nottorf, I. B. J o h n s and A. H. D a a n e . N u c l e o n i c s 4, 4 (1949).

IV. B. L u x . P l a n s e e b e r . P u l v e r m e t a l l u r g i e 4 , 7 (1956).

V. F . P a n e t h and K. P e t e r s . Z. p h y s i k . C h e m . 134, 364 (1928);

G. B r a u e r . Z. a n o r g . C h e m . 2 5 5 , 105 (1947).

I . H Y D R O G E N , D E U T E R I U M , W A T E R 1 1 7

Pure Wate r

T h e u s u a l l a b o r a t o r y d i s t i l l e d w a t e r c o n t a i n s c o n s i d e r a b l e a m o u n t s of d i s s o l v e d C 0² and, o c c a s i o n a l l y , t r a c e s of N H³a n d o r g a n i c s u b s t a n c e s .

T h i s d i s t i l l e d w a t e r m a y b e p u r i f i e d with C 0²- and N H³- f r e e a i r , which i s allowed to bubble t h r o u g h at 90°C for 24 h o u r s . The a i r s h o u l d b e d r a w n f r o m o u t s i d e t h e b u i l d i n g , s i n c e l a b o r a t o r y a i r i s often quite b a d l y c o n t a m i n a t e d . B e f o r e c o n t a c t i n g t h e w a t e r , t h e a i r p a s s e s s u c c e s s i v e l y t h r o u g h a w a s h b o t t l e filled with c o n - c e n t r a t e d H²S 0 4 , two b o t t l e s with NaOH, and one filled with p u r e w a t e r . Avoid long r u b b e r tubing c o n n e c t i o n s .

T h i s p r e p u r i f i e d w a t e r i s t h e n doubly d i s t i l l e d , f i r s t with a d d i - t i o n of s o m e NaOH and K M n 0⁴ and t h e n in t h e p r e s e n c e of a s m a l l q u a n t i t y of KHSO4. ^{T h e} c o n d e n s e r and i t s c o n n e c t i o n s should b e of Sn, P t o r q u a r t z . G l a s s c o n d e n s e r s m u s t b e avoided. It is a d v i s a b l e to b e n d t h e c o n d e n s e r o u t l e t at a r i g h t a n g l e and i n s e r t t h e l e g d i r e c t l y into t h e n e c k of t h e r e c e i v e r , u s i n g no s e a l i n g m a t e r i a l s (see F i g . 90). T o avoid c o n d e n s a t e s p r a y i n g , a v a p o r t r a p i s i n s t a l l e d b e f o r e t h e r e c e i v e r , a s shown in t h e f i g u r e (b).

c o n d e n s e r t o t h e r e -

c e i v e r ; a) s i m p l e and F i g < g i e D i s t i l l a t i o n o f " c o n d u c t i v i t y "

i n e x p e n s i v e ; b) with a ^{w a te re S T a re st a n da rd g r o U}n d j o i n t s , v a p o r t r a p .

T h e r e c e i v e r s should b e of q u a r t z , P t o r P y r e x and m u s t be t h o r o u g h l y s t e a m e d out b e f o r e u s e . The d i s t i l l a t i o n s h o u l d be s l o w and l a r g e v o l u m e s of f o r e r u n and r e s i d u e s h o u l d b e d i s c a r d e d . C o n t a c t with l a b o r a t o r y a i r s h o u l d b e a v o i d e d a s m u c h a s p o s s i b l e .

T h e p r o d u c t m a y b e t e s t e d for p u r i t y b y t h e c o n d u c t i v i t y m e t h o d . T h e f r e s h l y d i s t i l l e d p r o d u c t s h o u l d h a v e a c o n d u c t i v i t y of about l O ^ / o h m ^ c m r¹. It m a y b e t e s t e d for C O^s with B a ( O H )² s o l u t i o n and for N H³ with N e s s l e r ' s r e a g e n t .

V e r y p u r e w a t e r i s s t o r e d i n q u a r t z o r p l a t i n u m c o n t a i n e r s . P y r e x v e s s e l s m a y b e u s e d , if p r o p e r l y s t e a m e d o u t a n d if e m p l o y e d o n l y f o r w a t e r s t o r a g e . T h e r e c e i v e r n e c k s h o u l d h a v e a m a l e g r o u n d j o i n t a n d b e c l o s e d b y a c a p w i t h a f e m a l e j o i n t .

REFERENCES:

0 . H o n i g s c h m i d a n d R. S a c h t l e b e n . Z. a n o r g . a l l g . C h e m . 2 2 1 , 6 5 ( 1 9 3 4 ) ; O s t w a l d - L u t h e r . H a n d - u n d H i l f s b u c h z u r A u s f u h r u n g p h y s i k o c h e m i s c h e r M e s s u n g e n [ H a n d b o o k a n d M a n u a l f o r M a k i n g P h y s i c o c h e m i c a l M e a s u r e m e n t s ] , 5 t h E d . , L e i p z i g , 1 9 3 1 , p . 6 3 3 .

"CONDUCTIVITY" WATER

E x t r e m e l y p u r e w a t e r f o r c o n d u c t i v i t y m e a s u r e m e n t s i s o b ­ t a i n e d t h r o u g h v e r y c a r e f u l d i s t i l l a t i o n of a l r e a d y t h o r o u g h l y p u r i f i e d m a t e r i a l . T h i s p r e p u r i f i e d w a t e r ( c o n d u c t i v i t y a t 2 5 ° C :

1 - 2 · 1 0 ~6 o h m "1) i s o b t a i n e d e i t h e r v i a t h e m e t h o d d e s c r i b e d a b o v e o r t h r o u g h a n o t h e r d o u b l e d i s t i l l a t i o n p r o c e d u r e [the f i r s t d i s t i l l a t i o n w i t h K M n 04 + H2S 04, t h e s e c o n d w i t h B a ( O H )2, u s i n g a P y r e x a p p a r a t u s w i t h a t i n c o n d e n s e r ] .

1. S i n g l e - s t e p d i s t i l l a t i o n a c c o r d i n g t o t h e m e t h o d of K o r t i i m i s d o n e in t h e a p p a r a t u s s h o w n i n F i g . 9 1 . E x c e p t f o r t h e s h o r t q u a r t z c o n d e n s e r , t h e a p p a r a t u s i s m a d e o f P y r e x . A l l c o n ­ n e c t i o n s a r e m a d e w i t h g r o u n d j o i n t s , e x c e p t w h e r e i n d i c a t e d . T h e s e c t i o n b e t w e e n t h e r e f l u x c o n d e n s e r and t h e q u a r t z c o n ­ d e n s e r i s w o u n d w i t h a 6 0 - o h m h e a t i n g c o i l a n d h e a t e d t o 1 0 0 ° C i n o r d e r t o a v o i d c r e e p o v e r of l i q u i d w a t e r . T h e P y r e x r e f l u x c o n d e n s e r i s of t h e i n t e r n a l h e l i x t y p e . A g r o u n d j o i n t a d a p t e r c o n n e c t s t h e c o n d e n s e r a n d t h e r e c e i v e r . T h i s a d a p t e r and t h e r e c e i v e r s m u s t b e t h o r o u g h l y p r e s o a k e d i n h o t , d i l u t e a c i d s

( s e v e r a l d a y s ) t o r e m o v e a n y i m p u r i t i e s w h i c h m a y i n c r e a s e t h e c o n d u c t i v i t y of t h e p r o d u c t .

T h e p u r e w a t e r c h a r g e i s d i s t i l l e d i n a s t r e a m of a i r . C o m ­ p r e s s e d a i r f r o m a c y l i n d e r f l o w s a t a s l o w r a t e of 1 b u b b l e / s e c o n d t h r o u g h s e v e n w a s h b o t t l e s . In s u c c e s s i o n , t h e s e a r e f i l l e d w i t h c o n c e n t r a t e d H - S 0 4 (1 b o t t l e ) , 50% K O H (3 b o t t l e s ) a n d " c o n ­ d u c t i v i t y " w a t e r (3 b o t t l e s , p r e f e r a b l y w i t h g l a s s f r i t s ) . T h e s a m e c o m p r e s s e d p u r e a i r i s u s e d t o t r a n s f e r t h e p r o d u c t w a t e r f r o m t h e r e c e i v e r s t o s t o r a g e v e s s e l s . T h e t h r e e g r i d s h e a t i n g t h e d i s t i l l a t i o n f l a s k c o n s u m e a b o u t 3 0 0 w a t t s . In o r d e r t o i m ­ p r o v e t h e r a t e a n d u n i f o r m i t y of h e a t t r a n s f e r , t h e s p a c e b e ­ t w e e n t h e h e a t i n g g r i d a n d t h e d i s t i l l a t i o n f l a s k i s f i l l e d w i t h c e r a m i c b e a d s . T h e c e n t e r t u b e of t h e d i s t i l l i n g f l a s k p e r m i t s c h a r g i n g a n d e m p t y i n g t h e c o n t e n t s .

A c o n d u c t i v i t y c e l l i s a t t a c h e d t o t h e t h r e e - w a y s t o p c o c k a t t h e o u t l e t o f t h e c o n d e n s e r . T h e d i s t i l l a t e i s d i s c a r d e d u n t i l

1 . H Y D R O G E N , D E U T E R I U M , W A T E R

its c o n d u c t i v i t y m a t c h e s the d e s i r e d v a l u e . Only t h e n is t h e s y s t e m c o n n e c t e d to the r e c e i v e r .

T h e a p p a r a t u s d e l i v e r s 100 m l . / h r . of w a t e r h a v i n g a κ (25°C) = 2 · 1 0 ~⁷ o h m '¹. At v e r y low d i s t i l l a t i o n r a t e s , w a t e r with a κ (25°C) = 1 0 "⁸ ohm""¹ m a y b e o b t a i n e d .

II. " C o n d u c t i v i t y " w a t e r with κ (25°C) = 6 - 8 · 1 0 "⁸o h m "¹, in v o l u m e s l a r g e r t h a n t h o s e p r o v i d e d by t h e a p p a r a t u s of m e t h o d I, c a n b e o b t a i n e d with t h e i n s t a l l a t i o n of T h i e s s e n and H e r r m a n n . T h i s t w o - o r t h r e e - s t e p d i s t i l l a t i o n d o e s not r e q u i r e e x c e s s i v e l y c o m ­ p l e x e q u i p m e n t and i s c a p a b l e of d e l i v e r i n g 400 m l . / h r . of p r o ­ d u c t .

REFERENCES:

I. G. K o r t i i m . C h e m . F a b r i k 1 3 , 143 (1940).

II. P . A. T h i e s s e n and K. H e r r m a n n . C h e m . F a b r i k 10, 18 (1937);

Z . E l e k t r o c h e m . 4 3 , 66 (1937).

" p H - P U R E " W A T E R

T h e m e t h o d for o b t a i n i n g l a r g e q u a n t i t i e s of w a t e r with ρ Η = 7.00 i s b a s e d on addition of NaOH and K M n 0⁴ d u r i n g the f i r s t d i s t i l l a t i o n and H³P 0⁴ (to c o m b i n e t h e NH³) in t h e s e c o n d d i s ­ t i l l a t i o n s t e p . A t h i r d d i s t i l l a t i o n in q u a r t z a p p a r a t u s (to r e ­ m o v e t r a c e s of alkali) f o l l o w s .

REFERENCE:

E . L u x . Z. E l e k t r o c h e m . 4 8 , 215 (1942).

Deuteriu m an d Deuteriu m Compound s

D e u t e r i u m and the s i m p l e r i n o r g a n i c d e u t e r i u m c o m p o u n d s a r e c o m m e r c i a l l y a v a i l a b l e . N e v e r t h e l e s s , t h e r e s e a r c h c h e m i s t m a y o c c a s i o n a l l y be c a l l e d upon to p r e p a r e s o m e of t h e s e c o m ­ p o u n d s , s t a r t i n g with D²0 — t h e m o s t a v a i l a b l e of t h e d e u t e r i u m

c o m p o u n d s .

H e a v y w a t e r is m a n u f a c t u r e d in c o n c e n t r a t i o n s r a n g i n g f r o m 5 to 99.5% D²0 and is s o l d in s e a l e d g l a s s a m p o u l e s . P u r e h e a v y w a t e r i s v e r y h y g r o s c o p i c ; i . e . , it l o s e s D²0 v a p o r while s i m u l ­ t a n e o u s l y a b s o r b i n g a i r m o i s t u r e . T h e r e f o r e , c e r t a i n p r e c a u t i o n s m u s t be t a k e n when filling o r e m p t y i n g D²0 a m p o u l e s .

If only a p o r t i o n of t h e a m p o u l e c o n t e n t i s to be u s e d , t h e p o i n t e d end of t h e a m p o u l e i s h e a t e d in a s m a l l f l a m e and d r a w n out to a c a p i l l a r y with t o n g s . T h e c a p i l l a r y end is t h e n b r o k e n off and t h e d e s i r e d q u a n t i t y of D²0 d r i v e n out b y g e n t l e h e a t i n g ,

1 1 9

e . g . , by hand. T h e r e c e i v e r i s c l o s e d off a s s o o n a s p o s s i b l e and t h e a m p o u l e i s i m m e d i a t e l y r e s e a l e d with a f l a m e . It i s b e s t to s t o r e it in a d e s i c c a t o r .

T h e D²0 c o n t e n t s of an a m p o u l e m a y be p r e s e r v e d f r o m c o n ­ t a c t with a i r m o i s t u r e and s t i l l u t i l i z e d only p a r t i a l l y in t h e following w a y : t h e e n t i r e c o n t e n t s of t h e a m p o u l e a r e t r a n s ­ f e r r e d by t h e m e t h o d g i v e n b e l o w to an e l o n g a t e d f l a s k , c l o s e d off by a p i e r c a b l e , m e m b r a n e - t y p e r u b b e r s t o p p e r , s u c h a s u s e d for s e r u m v i a l s . Then t h e d e s i r e d a m o u n t s of D²0 c a n b e w i t h d r a w n f r o m t h e c l o s e d flask b y m e a n s of a h y p o d e r m i c s y r i n g e and i n ­ j e c t e d into o t h e r v e s s e l s , which c a n a l s o b e c l o s e d off with t h e s a m e type of s t o p p e r . T h e v e r y fine c a p i l l a r y p r o d u c e d in t h e r u b b e r s t o p p e r by t h e n e e d l e c l o s e s i m m e d i a t e l y upon w i t h ­ d r a w a l of t h e l a t t e r .

If t h e e n t i r e c o n t e n t s of an a m p o u l e a r e to b e u s e d in a r e a c t i o n , it is b e s t to b r e a k and e m p t y it i n s i d e t h e r e a c t o r itself, t h u s avoiding t r a n s f e r o p e r a t i o n s . To a c c o m p l i s h t h i s , t h e a m p o u l e is p l a c e d in a s n u g l y fitting v e s s e l , s u c h a s shown in F i g . 92. T h i s v e s s e l i s t h e n m e l t - s e a l e d to t h e r e a c t o r . T h e a p p a r a t u s i s t h e n c o n n e c t e d to a h i g h - v a c u u m s y s t e m . If a v o i d a n c e of dilution of t h e D²0 c o n t e n t i s c r i t i c a l , t h e e n t i r e a p p a r a t u s i s h e a t e d b y fanning with an open f l a m e to r e m o v e t h e f i l m of " l i g h t " w a t e r a c c u m u l a t e d on t h e i n t e r n a l s u r f a c e s . T h e v a c u u m i s t h e n d i s ­ c o n n e c t e d , t h e a p p a r a t u s i s c l o s e d off, and t h e v e s s e l c o n t a i n i n g t h e a m p o u l e i s r a p i d l y i m m e r s e d in liquid n i t r o g e n . T h e s u d d e n f r e e z i n g of t h e D^sO c a u s e s t h e a m p o u l e to s h a t t e r . Cooling with an a c e t o n e - D r y Ice m i x t u r e i s not sufficient, b e c a u s e t h e s o l i d i ­ fication of t h e D²0 t e n d s to b e s l o w e r and i t s c r y s t a l s b e g i n to g r o w m o s t l y in t h e u p p e r , e m p t y p a r t of t h e a m p o u l e . A l t e r n a t i v e l y , t h e a m p o u l e m a y b e b r o k e n b y a s u d d e n m o v e ­ m e n t of a g l a s s - e n c l o s e d i r o n b a r , s u s p e n d e d i n s i d e t h e r e a c t o r and s e t in m o t i o n b y an e l e c t r o m a g n e t .

All s u b s t a n c e s to be r e a c t e d with D^sO m u s t be c a r e f u l l y f r e e d of all t r a c e s of w a t e r . H y ­ g r o s c o p i c c o m p o u n d s , in which t h e u p t a k e of s m a l l a m o u n t s of H²0 d u r i n g c h a r g i n g of t h e r e a c t o r i s u n a v o i d a b l e , m u s t b e r e - d e h y d r a t e d in t h e r e a c t o r itself. T h i s i s done b y h e a t i n g (in high v a c u u m , if p o s s i b l e ) , d i s t i l l a t i o n o r r e s u b l i m a t i o n , w h e r e a p p l i c a b l e . Again, s u c h h y g r o s c o p i c c o m p o u n d s m a y b e e n c l o s e d in F i g . 9 2 . B r e a k - s e a l e d g l a s s a m p o u l e s i m m e d i a t e l y after t h e i r i n g DgO a m - p r e p a r a t i o n . T h e s e a m p o u l e s m a y t h e n b e i n - p o u l e s by f r e e z - s e r t e d into t h e r e a c t o r and b r o k e n w i t h a ing w i t h liquid m a g n e t - o p e r a t e d i r o n b a r , a s d e s c r i b e d

n i t r o g e n . a b o v e . t ^{t o}

I reactor

I . H Y D R O G E N , D E U T E R I U M , W A T E R 121 A s f a r a s p o s s i b l e , t h e a p p a r a t u s s h o u l d h a v e fused c o n n e c ­ t i o n s and c o n t a i n a m i n i m u m of s t o p c o c k s . If t h i s is not p o s s i b l e , s p e c i a l c a r e s h o u l d be t a k e n in s e a l i n g all p o s s i b l e l e a k s . D r y i n g t u b e s s h o u l d be i n s e r t e d b e t w e e n t h e a p p a r a t u s and i t s c o n n e c ­ t i o n s to t h e p u m p s (vacuum) o r to t h e a t m o s p h e r e . B e t t e r s t i l l , l i q u i d - n i t r o g e n - c o o l e d g a s t r a p s s h o u l d b e u s e d to p r e v e n t e n t r a n c e of a t m o s p h e r i c m o i s t u r e . Since in t h e p r e s e n c e of H²0 m o s t i n ­ o r g a n i c D c o m p o u n d s e x c h a n g e p a r t of t h e i r D c o n t e n t for H, t h e s e p r e c a u t i o n s m u s t b e o b s e r v e d in all r e a c t i o n s d e s c r i b e d in l a t e r s e c t i o n s .

L a r g e a m o u n t s of d e u t e r i u m c o m p o u n d s a r e e x p e n s i v e . It i s t h e r e f o r e a d v i s a b l e to p r a c t i c e e a c h r e a c t i o n with " l i g h t " s t a r t i n g m a t e r i a l b e f o r e a t t e m p t i n g t o u s e t h e D c o m p o u n d s .

REFERENCES:

1. C a t a l o g of t h e N o r s k H y d r o - E l e k t r i s k K v a e l s t o f a k t i e s e l s k a b , O s l o , S o l l i g a t e n 7, N o r w a y .

2 . I. W e n d e r , R. A. F r i e d e l and M. O r c h i n . J . A m e r . C h e m . Soc.

7 1 , 1140 (1949); M, O r c h i n and I. W e n d e r . A n a l y t . C h e m . 2 1 , 875 (1949).

3 . J . W. Knowlton and F . D . R o s s i n i . J . R e s . Nat. B u r . S t a n d a r d s 19, 605 (1937).

Deuteriu m D²

I. 2 D²0 + 2Na = D² 4- 2NaOD

40.06 45.99 4.03 82.02

F l a s k Ε of t h e g l a s s a p p a r a t u s shown in F i g . 93 c o n t a i n s an Al c r u c i b l e with e x c e s s m e t a l l i c s o d i u m . V e s s e l V c o n t a i n s t h e D²0 r e a g e n t . The l a t t e r i s i n t r o d u c e d (as d e s c r i b e d above) in t h e a b s e n c e of a t m o s p h e r i c m o i s t u r e . After cooling V with liquid n i t r o g e n , t h e a p p a r a t u s i s c a r e f u l l y e v a c u a t e d , with s t o p ­ c o c k s 1 and 2 o p e n . Stopcock 2 i s t h e n c l o s e d and t h e D²0 i s d i s ­ t i l l e d s l o w l y onto t h e N a by cooling Ε with liquid n i t r o g e n . To c o m p l e t e t h e r e a c t i o n , Ε i s t h e n h e a t e d for s e v e r a l h o u r s to 350°C.

After o p e n i n g s t o p c o c k 2, t h e D² p r o d u c e d i s t r a n s f e r r e d for p u r i f i c a t i o n into a r e c e p t a c l e filled with d e g a s s e d c h a r c o a l and left t h e r e for s o m e t i m e at —196°C. If f r e s h N a i s u s e d , the D² p r o d u c t will s t i l l c o n t a i n s o m e few p e r c e n t of Η ² a f t e r t h e p u r i ­ fication (this H² w a s d i s s o l v e d in t h e m e t a l and e x i s t e d a s NaOH).

P u r e D², c o n t a i n i n g l e s s t h a n 0.2% H² and o t h e r f o r e i g n g a s e s , is only o b t a i n e d in t h e s e c o n d r u n with t h e s a m e p i e c e of N a .

high vacuum

F i g . 9 3 . P r e p a r a t i o n of D2 f r o m DsO a n d N a .

T h e g a s i s t e s t e d f o r p u r i t y b y m e a s u r e m e n t of t h e t h e r m a l c o n ­ d u c t i v i t y o r v a p o r p r e s s u r e . T h e y i e l d o f D? i s q u a n t i t a t i v e .

T h e m e t h o d i s e s p e c i a l l y s u i t a b l e f o r t h e p r e p a r a t i o n of s m a l l a m o u n t s of D2 (up t o o n e l i t e r ) .

In a n e l o n g a t e d f l a s k of a P y r e x a p p a r a t u s , p r e - e v a c u a t e d t o 1 0 "4 m m . , 2 0 g . of D2 lO i s s l o w l y e v a p o r a t e d . T h e v a p o r p a s s e s t h r o u g h t h e r e a c t i o n t u b e , s e t v e r t i c a l l y o n t o p o f t h e f l a s k . T h e t u b e (I.D. 2 . 4 c m . a n d 5 5 c m . l o n g ) c o n t a i n s 1 3 0 g . of M g s h a v i n g s o f v a r i o u s s i z e s , w i t h c o a r s e p a r t i c l e s o n t h e b o t t o m a n d l o o s e p o w d e r o n t o p . T h e c o l u m n f i l l i n g i s s u p p o r t e d b y a p e r f o r a t e d p l a t i n u m d i s k w h i c h r e s t s o n g l a s s l u g s i n s i d e t h e t u b e . T h e M g i s h e a t e d t o 4 8 0 ° C b y a t u b u l a r f u r n a c e .

A f t e r a n e x t e n d e d p e r i o d of t i m e , s o m e m a g n e s i u m s u i c i d e w i l l f o r m o n t h e w a l l s o f t h e h e a t e d g l a s s t u b e . T o a v o i d t h i s , it i s s u g g e s t e d t h a t t h e M g b e p l a c e d i n a t u b e of u n g l a z e d h a r d p o r c e l a i n w h i c h i s t h e n i n s e r t e d i n t o a P y r e x o r V y c o r t u b e a n d m e l t - s e a l e d t o t h e l a t t e r at o n e e n d . With s u c h a n a r r a n g e m e n t t h e M g m a y e v e n b e h e a t e d t o a s o m e w h a t h i g h e r t e m p e r a t u r e a n d i t s r e a c t i v i t y t h u s e n h a n c e d .

F o r p u r i f i c a t i o n , t h e D2 p r o d u c t p a s s e s t h r o u g h a t r a p f i l l e d w i t h g l a s s w o o l a n d k e p t at — 1 9 6 C . It i s t a k e n o u t f r o m t h e g e n e r a t o r a s q u i c k l y a s p o s s i b l e , e i t h e r b y c o n d e n s a t i o n w i t h l i q u i d H2 o r b y f o r c i n g it i n t o an a t t a c h e d s t o r a g e c o n t a i n e r . A n i n - l i n e f l o w m e t e r a n d a m a n o m e t e r a l l o w c o n s t a n t c h e c k i n g o f p r e s s u r e . T h e r a t e of e v o l u t i o n c a n b e c o n t r o l l e d b y v a r y i n g t h e

s u p p l y of h e a t t o t h e D^sO f l a s k . A m a x i m u m f l o w of 0 . 5 m o l e o f D²/ h o u r m a y b e o b t a i n e d . S i n c e t h e f i r s t D² f r a c t i o n m a y b e

II. D20 + Mg = D2 + MgO

20.03 24.32 4.03

I . H Y D R O G E N , D E U T E R I U M , W A T E R 1 2 3

c o n t a m i n a t e d w i t h s o m e H² f r o m t h e M g a n d f r o m t h e a p p a r a t u s w a l l s , it i s a d v i s a b l e t o c o l l e c t s o m e of t h e f i r s t D2 f r a c t i o n i n a s e p a r a t e v e s s e l . T h e D2 f o r m e d l a t e r i s v e r y p u r e . T h e y i e l d i s q u a n t i t a t i v e .

T h i s m e t h o d a l l o w s r a p i d p r o d u c t i o n of l a r g e a m o u n t s of D2

a n d u t i l i z e s t h e e n t i r e D c o n t e n t o f t h e h e a v y w a t e r .

ΠΙ. a) 2 D20 + U = U 02 + 2 D2

40.06 238.07 270.07 8.06 b) 3 D² + 2 U = 2 U D³

12.09 476.14 488.23

T h i s m e t h o d i s e s p e c i a l l y u s e f u l i n t h a t it m a k e s p o s s i b l e b o t h t h e p r e p a r a t i o n ( E q . a) a n d t h e s t o r a g e ( a s U D³— E q . b) of D². H i g h - p u r i t y D2 c a n t h e n b e l i b e r a t e d b y t h e r m a l d e c o m p o s i t i o n of t h e U D3. A n y d e s i r e d q u a n t i t y of v e r y p u r e D2 c a n t h u s b e o b ­ t a i n e d w h e n n e e d e d .

T h e h i g h l y e n d o t h e r m i c r e a c t i o n of D20 v a p o r w i t h U m a y b e c a r r i e d o u t s l o w l y a n d s a f e l y i n t h e a p p a r a t u s of F i g . 9 4 . T h e 5 0 - m l . f l a s k a i s c o n n e c t e d b y s t o p c o c k h1 w i t h m a n o m e t e r b a n d q u a r t z r e a c t i o n t u b e d. R e a c t o r d i s h e a t e d w i t h a n e l e c t r i c f u r n a c e t o 6 0 0 - 7 0 0 ° C a n d i s c o n n e c t e d t o a l i q u i d - n i t r o g e n - c o o l e d t r a p / . T h e l a t t e r i s , i n t u r n , c o n n e c t e d t o a h i g h - v a c u u m p u m p a n d a f l a s k g w h i c h m a y b e h e a t e d t o 2 5 0 ° C .

F l a s k α i s a b o u t h a l f f i l l e d w i t h D²0 a n d d a n d q w i t h u r a n i u m s h a v i n g s (the u r a n i u m i s p r e t r e a t e d w i t h d i l u t e H N 03 t o r e m o v e a l l o x i d e , t h e n w a s h e d a n d d r i e d ) . T h e s h a v i n g s i n r e a c t o r d a r e s u p p o r t e d o n a n d c o v e r e d w i t h g l a s s w o o l p l u g s cx a n d ο 2. T h e DsO i n α i s t h e n f r o z e n w i t h a D r y I c e - m e t h a n o l b a t h ; t h i s m u s t b e d o n e s l o w l y t o a v o i d c r a c k i n g t h e f l a s k . T h e e n t i r e a p p a r a t u s i s t h e n e v a c u a t e d , w h i l e g a n d d a r e h e a t e d . T h e D 20 i s t h e n c a r e ­ f u l l y m e l t e d a n d t h e r e a c t i o n i s s l o w l y s t a r t e d b y a l l o w i n g t h e v a p o r t o p e n e t r a t e t o t h e u r a n i u m i n d. T h e f i r s t D2 e v o l v e d i s u s e d t o f l u s h t h e a p p a r a t u s , w i t h s t o p c o c k h3 c l o s e d . O n l y t h e n i s h4 c l o s e d a n d h3 o p e n e d . D u r i n g t h e r e a c t i o n , a i s k e p t at a b o u t 3 0 ° C . T h e D2 p r o d u c t p a s s e s t h r o u g h t r a p / , i n w h i c h a n y e n t r a i n e d t r a c e s of D20 a r e f r o z e n o u t , a n d i s a b s o r b e d b y t h e u r a n i u m s h a v i n g s i n g, f o r m i n g U D3. W h e n a l l of t h e U i s f i n a l l y c o n v e r t e d t o U D3, t h e e x c e s s D2 c a u s e s a n i n c r e a s e i n p r e s s u r e w h i c h s u p p r e s s e s t h e e v a p o r a t i o n o f D20 a n d t h e r e b y p r e v e n t s a n y f u r t h e r D2 f o r m a t i o n . T h u s , o n c e s t a r t e d , t h e p r o c e s s i s s e l f - r e g u l a t i n g a n d r e q u i r e s n o s p e c i a l a t t e n t i o n . S e v e r a l g r a m s of D20 c a n b e c o n v e r t e d i n t o U D3 i n o n e h o u r .

T h e U D3 i s a b r o w n - b l a c k , s p o n t a n e o u s l y i g n i t i n g p o w d e r . T o p r e p a r e v e r y p u r e D2, it i s t h e r m a l l y d e c o m p o s e d e i t h e r a t a t ­

m o s p h e r i c o r r e d u c e d p r e s s u r e ( s e e a l s o H2 a b o v e : III). T h e U

F i g , 9 4 . P r e p a r a t i o n and s t o r a g e of d e u t e r i u m , a) D^sO r e s e r v o i r ; b) m a n o m e t e r ; ο ¹, ο ²) g r o u n d j o i n t s ; d) q u a r t z tube c o n t a i n i n g U t u r n i n g s ; f) trap;gr) r e a c t i o n f l a s k c o n ­

t a i n i n g U t u r n i n g s ; h^h^) s t o p c o c k s .

p o w d e r t h u s f o r m e d (at 400°C o r l o w e r t e m p e r a t u r e s ) r e a c t s v i g o r o u s l y with H o (or at r o o m t e m p e r a t u r e and s t i l l quite v i g o r o u s l y at —80 C Only at —200°C d o e s t h e r e a c t i o n c e a s e .

IV. ELECTROLYSIS OF D20

An e l e c t r o l y t i c c e l l , holding 60 m l . of liquid and m a d e f r o m a s t a n d a r d g r o u n d g l a s s joint, is shown in F i g . 95. The m a l e p a r t of t h e g r o u n d joint c o n t i n u e s into a c y l i n d r i c a l w a t e r j a c k e t (only p a r t l y shown in the d i a g r a m ) which s u r r o u n d s t h e c a t h o d e . The P t e l e c t r o d e s a r e a l s o c y l i n d r i c a l and a r e p r e p a r e d by fusing t o g e t h e r a P t w i r e with a P t foil. T h e D²0 e l e c t r o l y t e i s acidified with 25% D²S 0⁴. (If no D²S 0⁴ i s a v a i l a b l e , c a r e f u l l y d e h y d r a t e d K²S 0⁴ o r N a²C 0³ c a n a l s o be u s e d . ) After e v a c u a t i o n of t h e c e l l at A and B⁹ e l e c t r o l y s i s i s begun at a low c u r r e n t to p r e v e n t f o a m i n g at low p r e s s u r e s . After a s h o r t t i m e , h o w e v e r , t h e c u r r e n t c a n be i n c r e a s e d to 5 a m p . The t e m p e r a t u r e of t h e e l e c t r o l y t e m u s t not be allowed to r i s e . If t h e D² p r o d u c t g a s i s to o v e r c o m e t h e p r e s s u r e d r o p due to n a r r o w t u b e s and a liquid h e a d in t h e a t t a c h e d p u r i f i c a t i o n a p p a r a t u s o r r e a c t o r , t h e p r e s s u r e in t h e c e l l m u s t be m a i n t a i n e d at a h i g h e r l e v e l by m e a n s of a t h r o t t l i n g

I . H Y D R O G E N , D E U T E R I U M , W A T E R 1 2 5

F i g . 9 5 . E l e c t r o l y s i s of D²0 .

v a l v e in t h e 0² o u t l e t . T h e D ² p r o d u c t s t i l l c o n t a i n s s m a l l a m o u n t s of Ο ² and D²0 v a p o r . V e r y p u r e g a s m a y b e o b t a i n e d by h e a t i n g t h e e l e c t r o l y s i s p r o d u c t o v e r p l a t i n i z e d a s b e s t o s , followed by d r y i n g with liquid n i t r o g e n . At 5 a m p . , two l i t e r s of D²p e r h o u r i s o b t a i n e d .

S m a l l q u a n t i t i e s of D² a r e s t o r e d in s e a l e d g l a s s f l a s k s o r o v e r m e r c u r y . D i s t i l l e d w a t e r c a n a l s o b e u s e d a s a s e a l i n g liquid.

L a r g e r a m o u n t s m a y b e c o n d e n s e d in a m e t a l f l a s k c o o l e d with liquid Η ². T h e liquid i s t h e n h e a t e d and t h u s f o r c e d t h r o u g h m e t a l tubing into s m a l l s t e e l c y l i n d e r s .

O t h e r e q u i p m e n t for e l e c t r o l y s i s of D²0 , s o m e of which i s a p p l i c a b l e to s m a l l - s c a l e o p e r a t i o n , i s d e s c r i b e d b y : F . N o r l i n g , P h y s i k . Z. 3 6 , 711 (1935); C. M. Slack and L . F . E h r k e , R e v . Sci.

I n s t r u m e n t s (N.S.) 8, 39 (1937); A. S i e v e r t s and W. D a n z , Z . P h y s . C h e m . Β 3 8 , 46 (1937); Μ. Μ. Winn, J . S c i . I n s t r u m e n t s 2 8 , 152 (1951); J . T. L l o y d , J . Sci. I n s t r u m e n t s 2 9 , 164 (1952);

R. W. Waniek, R e v . Sci. I n s t r u m e n t s 2 1 , 262 (1950).

V. Other preparative methods: R e d u c t i o n of D²0 with F e o r W at h i g h t e m p e r a t u r e s .

SYNONYM:

Heavy h y d r o g e n .

PROPERTIES:

C o l o r l e s s , o d o r l e s s g a s . C h e m i c a l p r o p e r t i e s a n a l o g o u s to H², but s o m e w h a t l e s s r e a c t i v e . In t h e a b s e n c e of c a t a l y s t s , m i x t u r e s of D² and H² a r e s t a b l e to about 500°C. In a d d i t i o n , no e x c h a n g e with H²0 o c c u r s at r o o m t e m p e r a t u r e . M.p. —254.6°C, b . p . - 2 4 9 . 7 ° C ; d (liq., - 2 5 3 . 1 ° C ) 0 . 1 7 1 . V e r y s l i g h t l y s o l u b l e in w a t e r and o t h e r l i q u i d s .

REFERENCES:

I. G. N. L e w i s and W. T. H a n s o n . J . A m e r . C h e m . Soc. 56, 1687 (1934).

II. J . W. Knowlton and F . D. R o s s i n i . J . R e s . N a t . B u r . S t a n d a r d s 19, 605 (1937); u n p u b l i s h e d e x p e r i m e n t s of G. B r a u e r .

ΙΠ. F . H. Spedding, A. S. Newton, J . C Warf, O. J o h n s o n , R. W.

Nottorf, I. B. J o h n s and A. H. D a a n e , N u c l e o n i c s 4, 4 (1949).

IV. C. L. Wilson and A. W. Wylie. J . C h e m . S o c (London) 1 9 4 1 , 596.

V. E . Z i n t l and A. H a r d e r . Z. p h y s . C h e m . Β 2 8 , 480 (1935);

A. F a r k a s and L. F a r k a s . P r o c . Roy. Soc. London 144, 469 (1934).

Hydroge n Deuterid e

H D

LiAlH⁴ + 4 D²0 = LiOD + Al(OD)³ + 4 HD

37.94 80.12 24.96 81.02 12.09

T h i s r e a c t i o n i s c o n d u c t e d in a 2 5 0 - m l . t w o - n e c k f l a s k p r o ­ vided with a r e f l u x c o n d e n s e r and a m a g n e t i c s t i r r e r . The o t h e r n e c k of the flask is c l o s e d with a r u b b e r c a p . T h e r e f l u x c o n d e n s e r i s c o n n e c t e d to a r e c e i v e r and a diffusion p u m p via cold t r a p s , w h e r e t h e e n t r a i n e d liquid is c o n d e n s e d . G a s i n l e t l i n e s with s t o p ­ c o c k s a l l o w e a c h p a r t of t h e a p p a r a t u s to b e e v a c u a t e d s e p a r a t e l y o r , if d e s i r e d , to be filled with a i r o r N².

About 150 m l . of η - b u t y l e t h e r , d r i e d o v e r Na, i s d i s t i l l e d into t h e r e a c t i o n flask and 5.75 g. of L i A l H⁴ (40% e x c e s s ) i s t h e n added u n d e r a n i t r o g e n b l a n k e t . T h e m i x t u r e i s f r o z e n with liquid Ν ². T h e a p p a r a t u s i s t h e n e v a c u a t e d , and t h e f l a s k c o n t e n t s a r e b r o u g h t to boiling by c a r e f u l h e a t i n g . After 1.5 h o u r s , it i s a g a i n

I . H Y D R O G E N , D E U T E R I U M , W A T E R 1 2 7

c o o l e d with liquid N², t h e e v a c u a t i o n i s r e p e a t e d , and 5 m l . of 99.5% D²0 (see a b o v e , D²0 ) i s a d d e d to t h e s o l i d i f i e d m i x t u r e , u s i n g a h y p o d e r m i c s y r i n g e to p i e r c e t h e r u b b e r c a p . T h e g a s evolution i s s t a r t e d by m e l t i n g t h e m i x t u r e and a g i t a t i n g with t h e m a g ­ n e t i c s t i r r e r . B e c a u s e of t h e low r e a c t i o n t e m p e r a t u r e , t h e f l a s k b e c o m e s c o a t e d with i c e on t h e o u t s i d e . By r e p e a t e d i m m e r s i o n in liquid N^s, t h e t e m p e r a t u r e i s c o n t r o l l e d s o t h a t t h e i c e on t h e o u t e r w a l l of t h e flask d o e s not m e l t . A s s o o n a s t h e r e a c t i o n s u b s i d e s s o m e w h a t , two a d d i t i o n a l p o r t i o n s of 6.5 m l . of D^sO e a c h a r e a d d e d (for a t o t a l of 18 m l . o r 150% e x c e s s ) . The y i e l d i s 10 l i t e r s of HD. T h e p u r i t y i s 9 7 - 9 9 % .

PROPERTIES:

C o l o r l e s s , o d o r l e s s g a s . B . p . —251.02°C; t r i p l e p o i n t —256.55°C (92.8 m m . ) .

REFERENCES:

A. F o o k s o n , P . P o m e r a n t z and Ε . H. R i c h . J . R e s . N a t . B u r . S t a n d a r d s 4 7 , 31 (1951); S c i e n c e (New York) 1 1 2 , 748 (1950).

J . W e n d e r , R. A. F r i e d e l and M. O r c h i n . J . A m e r . C h e m . Soc. 7 1 , 1140 (1949).

R. B. Scott and F . G. B r i c k w e d d e . P h y s . R e v . (2) 4 8 , 483 (1935);

5 5 , 672 (1939).

Deuteriu m Fluorid e

D F

I. D² + 2 AgF = 2 DF + 2Ag

4.03 253.76 42.03 215.76

S o m e d r y A g F i s c h a r g e d into a s i l v e r r e a c t i o n f l a s k p r o v i d e d with a m a n o m e t e r and an i n l e t t u b e t h a t c a n b e c l o s e d off. T h e A g F c a n a l s o b e p r o d u c e d by t h e a c t i o n of F² on t h e i n n e r w a l l s of t h e flask itself. After e v a c u a t i o n , p u r e , c a r e f u l l y d r i e d D²

(see a b o v e , D²) i s a d m i t t e d into t h e f l a s k . T h e l a t t e r i s t h e n c l o s e d and h e a t e d to 110°C until t h e p r e s s u r e c e a s e s to c h a n g e . T h e D F f o r m e d i s f r o z e n out of t h e r e a c t i o n m i x t u r e by cooling with liquid n i t r o g e n , and e x c e s s D² i s d r a w n off by s u c t i o n a f t e r o p e n i n g t h e f l a s k . The, p r o d u c t i s p u r i f i e d by h i g h - v a c u u m d i s t i l l a ­ t i o n in which all c o n n e c t i o n s and r e c e i v e r s m u s t b e of Ag o r Cu.

To d a t e , t h i s m e t h o d h a s b e e n u s e d o n l y for p r o d u c i n g s m a l l a m o u n t s of D F . D e u t e r i u m f l u o r i d e m a y b e s t o r e d in v e s s e l s m a d e of p l a t i n u m , s i l v e r o r c o p p e r .

Π. 2 C^eH⁵C O F + D²0

248.22 20.03

(C^eH⁵CO)²0 + 2 D F

226.22 42.03

T h e r e a c t i o n i s c a r r i e d out in t h e a p p a r a t u s shown in F i g . 96.

T h e l a t t e r i s flushed out with d r y Ν ², and a t m o s p h e r i c m o i s t u r e i s s t r i c t l y e x c l u d e d .

S i l v e r f l a s k a i s c h a r g e d w i t h 168 g. (1.5 m o l e s ) of b e n z o y l f l u o r i d e a n d c h i l l e d w i t h D r y I c e - a c e t o n e f r e e z i n g m i x t u r e . T h e n 5 g.

(0.25 m o l e ) of 99.5% D²0 is added all at o n c e u n d e r N². T h e flask i s t h e n a t t a c h e d to t h e s i l v e r d i s t i l l a t i o n a p p a r a t u s . B r i n e at

—15°C i s c i r c u l a t e d t h r o u g h t h e c o n d e n s e r o^t and t h e q u a r t z r e ­ c e i v e r i s c o o l e d with D r y I c e - a c e t o n e to — 80°C. Cooling of

F i g . 96. P r e p a r a t i o n of d e u t e r i u m f l u o r i d e . a) S i l v e r f l a s k ; b) t h e r m o m e t e r w e l l ; o)

j a c k e t e d g l a s s c o n d e n s e r ; d) p a r a f f i n - c o a t e d s t o p p e r ; e) c a l c i u m c h l o r i d e t u b e ; / ) q u a r t z

r e c e i v e r .

flask a i s t h e n c e a s e d and t h e l a t t e r i s s l o w l y h e a t e d to r o o m t e m p e r a t u r e : t h e evolving D F i s t h e n d i s t i l l e d on a w a t e r b a t h at 8 0 - 9 0 ° C . T o a c h i e v e a n a l y t i c a l p u r i t y and s e p a r a t e e n t r a i n e d b e n z o y l f l u o r i d e , t h e d i s t i l l a t i o n i s r e p e a t e d t w i c e . T h e y i e l d i s 9.7 g. of D F (92% of t h e o r e t i c a l ) .

III. L a r g e r q u a n t i t i e s of D F c a n b e p r e p a r e d b y s y n t h e s i s f r o m t h e e l e m e n t s a c c o r d i n g to a m e t h o d d e s c r i b e d b y H. von W a r t e n - b e r g for t h e p r o d u c t i o n of H F ; h o w e v e r , t h i s r e q u i r e s e x t e n s i v e e q u i p m e n t .

IV. A q u e o u s s o l u t i o n s of d e u t e r a t e d h y d r o f l u o r i c a c i d c a n b e p r e p a r e d by t h e c o n d e n s a t i o n of D F in D²0 o r by t h e r e a c t i o n of v e r y p u r e C a F² with D²S 0⁴ (see a l s o p r e p a r a t i o n of p u r e h y ­ d r o f l u o r i c a c i d , p . 145 ff.).

I . H Y D R O G E N , D E U T E R I U M . W A T E R 1 2 9

PROPERTIES:

F o r m u l a weight 2 1 . 0 1 . C o l o r l e s s , w a t e r l i k e liquid; p u n g e n t o d o r ; f u m e s in m o i s t a i r . T h e v a p o r s a r e v e r y t o x i c . C h e m i c a l p r o p e r t i e s a n a l o g o u s t o H F . T h e d e u t e r i u m i s e x c h a n g e d for h y d r o g e n in t h e p r e s e n c e of H⁺. B.p. +18.6°C. V e r y r e a d i l y s o l u b l e in w a t e r .

REFERENCES:

I. W. H. C l a u s e n and J . H. H i l d e b r a n d . J . A m e r . C h e m . Soc.

56, 1820 (1934).

Π. G. O l a h and S. Kuhn. Z. a n o r g . a l l g . C h e m . 2 8 7 , 282 (1956).

III. H. von W a r t e n b e r g a n d O. F i t z n e r . Z . a n o r g . a l l g . C h e m . 1 5 1 , 313 (1926).

Deuteriu m Chlorid e DC1

I. 2C^eH⁵COCl + D²0 = (C^eH⁵CO)²0 + 2DC1

281.13 20.03 226.22 74.94

T h e a p p a r a t u s shown in F i g . 97 m a y b e e n l a r g e d if l a r g e r a m o u n t s of DC1 a r e d e s i r e d . T h e long c a p i l l a r y t u b e f r o m d r o p p i n g funnel t, which r e a c h e s into t h e r e a c t i o n f l a s k r t h r o u g h t h e c o n ­ d e n s e r k, e n s u r e s u n i f o r m a d d i t i o n of D^sO to t h e b e n z o y l c h l o r i d e in t h e f l a s k in s p i t e of s m a l l f l u c t u a t i o n s of p r e s s u r e d u r i n g t h e r e a c t i o n . In o r d e r to t r a p any b e n z o y l c h l o r i d e e n t r a i n e d t h r o u g h t h e c o n d e n s e r by t h e DC1 g a s , t r a p / i s c o o l e d in an i c e b a t h . M a n o m e t e r m (with one a r m o p e n to t h e a i r ) s e r v e s b o t h a s a s a f e t y v a l v e and a s a m e a n s for following t h e c o u r s e of t h e r e a c t i o n (if t h e o u t l e t t u b e i s c l o s e d off, t h e m a n o m e t e r will s h o w w h e t h e r t h e g a s c o n t i n u e s to e v o l v e ) .

A s an e x a m p l e of DC1 p r e p a r a t i o n , 5 m l . of 99.6% D^sO i s a l l o w e d to r e a c t with 210 g. of b e n z o y l c h l o r i d e (2-3 m o l a r e x c e s s ) c o n ­ t a i n i n g s o m e p o r o u s b o i l i n g c h i p s . At f i r s t , only a few d r o p s of D^aO a r e a d d e d , while t h e m i x t u r e i s c a r e f u l l y h e a t e d . T h i s i s c o n t i n u e d until a m o d e r a t e g a s s t r e a m i s d e v e l o p e d . T h i s t e m ­ p e r a t u r e i s m a i n t a i n e d u n t i l all of t h e D²0 i s a d d e d . By v a r y i n g t h e h e a t input, g a s f o r m a t i o n c a n e a s i l y b e r e g u l a t e d . A s t h e flow d e c r e a s e s , t h e t e m p e r a t u r e i s s l o w l y i n c r e a s e d to t h e b o i l i n g p o i n t of b e n z o y l c h l o r i d e (197°C) and k e p t t h e r e until no f u r t h e r g a s i s e v o l v e d . At t h e end of t h e r e a c t i o n , a s t r e a m of d r y a i r i s s l o w l y i n t r o d u c e d into t h e a p p a r a t u s t h r o u g h t h e d r o p ­ p i n g funnel, without i n t e r r u p t i n g t h e r e f l u x i n g , to e x p e l all t h e DC1. T h e p r o d u c t i s a n a l y t i c a l l y p u r e and t h e y i e l d i s a l m o s t q u a n t i t a t i v e .

υ

F i g . 9 7 . P r e p a r a t i o n of DC1 f r o m h e a v y w a t e r and b e n z o y l c h l o r i d e . / ) C o n ­ d e n s a t i o n t r a p ; h) r e f l u x c o n d e n s e r ; m) open a r m m a n o m e t e r ; r) r e a c t i o n f l a s k ; t) d r o p p i n g funnel

w i t h c a p i l l a r y s t e m .

II. SiCl⁴ + 2 D²0 = 4 DC1 + Si0²

169,89 40.06 149,88

Two t h i n - w a l l , v a c u u m - s e a l e d a m p o u l e s c o n t a i n i n g 18 g. of c a r e ­ fully p u r i f i e d S i C l⁴ and 1.8 g. of D^sO a r e s h a t t e r e d by s h a k i n g in an e v a c u a t e d f i v e - l i t e r f l a s k p r o v i d e d with a g l a s s s t o p p e r with a s t o p c o c k s e a l e d in. After 24 h o u r s t h e flask i s s e a l e d t o a h i g h - v a c u u m s y s t e m and t h e c r u d e g a s c o n d e n s e d in a l i q u i d - n i t r o g e n - c o o l e d t r a p . T h e p r o d u c t m a y b e f u r t h e r p u r i f i e d a s in I o r , e v e n b e t t e r , with a l o w - t e m p e r a t u r e d i s t i l l a t i o n c o l u m n (see o r i g i n a l l i t e r a t u r e for d e t a i l s ) .

L i q u i d d e u t e r i u m c h l o r i d e c a n b e s t o r e d at low t e m p e r a t u r e . T h e g a s m a y b e s t o r e d in a s e a l e d g l a s s flask o r o v e r m e r c u r y .

Other preparative methods:

III. R e a c t i o n of a n h y d r o u s M g C l² with D^aO a t 600°C:

MgCl² + D²0 = 2 DC1 + MgO.

Y i e l d s v e r y p u r e DC1 on d i s t i l l a t i o n . IV. R e a c t i o n of v e r y p u r e N a C l with D²S 0⁴.

A q u e o u s s o l u t i o n s of h e a v y h y d r o c h l o r i c a c i d a r e p r e p a r e d by c o n d e n s a t i o n of DC1 in D^sO .

SYNONYM:

Heavy h y d r o g e n c h l o r i d e .

PROPERTIES:

F o r m u l a weight 37.47. C h e m i c a l p r o p e r t i e s a n a l o g o u s to HC1.

In t h e a b s e n c e of m o i s t u r e and c a t a l y s t s , no d e u t e r i u m e x c h a n g e o c c u r s in g a s e o u s m i x t u r e s of HC1 and DC1. H o w e v e r , an e x ­ c h a n g e r e a c t i o n o c c u r s i n s t a n t a n e o u s l y in s o l v e n t s c o n t a i n i n g H⁺. M.p. - 1 1 4 . 8 ° C , b . p . - 8 1 . 6 ° C , t^{c r} +50.3°C.

REFERENCES:

I. H. C. B r o w n and C. G r o o t . J . A m e r . C h e m . Soc. 64, 2223 (1942).

II. K. C l a u s i u s and G. Wolf. Z. N a t u r f o r s c h . 2 a , 495 (1947).

I . H Y D R O G E N , D E U T E R I U M , W A T E R 1 3 1

III. G. N. L e w i s , R. T. M a c d o n a l d and P . W. Schutz. J . A m e r . C h e m . Soc. 56, 494 (1934).

IV. A. S m i t s , G. J . M u l l e r and F . A. K r o g e r . Z. p h y s . C h e m . B38, 177 (1937); s e e a l s o Ο. E . F r i v o l d , O. H a s s e l and S.

R u s t a d . P h y s . Z. 3 8 , 191 (1937).

Deuteriu m Bromid e DBr

I. D² + Br² = 2 DBr

4,03 159.83 163.86

T h e g l a s s a p p a r a t u s s h o w n in F i g . 98 i s u s e d . P r i o r t o t h e r u n , it is e v a c u a t e d for a c o n s i d e r a b l e t i m e via P . F l a s k 0 i s c h a r g e d with c a r e f u l l y p u r i f i e d B r² f r o m (see s e c t i o n on B r²) by m o v i n g t h e p l u g S of t h e d r o p p i n g funnel (which h a s no s t o p c o c k ) . T h e flask is t h e n h e a t e d to 48 C. D r y D² ( s e e p . 121) e n t e r s at A at a r a t e of about two l i t e r s / h o u r and p a s s e s t h r o u g h s t o p c o c k Β ( l u b r i c a t e d with p h o s p h o r i c a c i d - g r a p h i t e and s e a l e d with m e r c u r y ) into 0, w h e r e it m i x e s with t h e b r o m i n e v a p o r which i s r e p l e n i s h e d d u r i n g t h e r e a c t i o n f r o m t h e d r o p p i n g funnel. T h e Dtg-Brs m i x ­ t u r e flows into t h e V y c o r c o m b u s t i o n t u b e Β, which i s filled with

F i g . 9 8 . P r e p a r a t i o n of D B r . B) Hg s e a l s t o p ­ c o c k , l u b r i c a t e d with g r a p h i t e - p h o s p h o r i c acid; D) b r o m i n e s t o r a g e v e s s e l ; 0) r e a c t i o n flask; JR) V y c o r t u b e filled with p o r c e l a i n c h i p s ; Ε, F) c o n d e n s a t i o n t r a p s ; K) c o l u m n

with Cu t u r n i n g s .