SECTION 7
Sulfur, Selenium, Tellurium
F. FEHER
Sulfu r s
PURE SULFUR
C o m m e r c i a l sulfur c a n b e p u r i f i e d t o a c o n s i d e r a b l e e x t e n t by r e p e a t e d r e c r y s t a l l i z a t i o n f r o m C S3.
A s o l u t i o n of 31.5 g. of S in 70 g. of C S3 ( C . P . ) i s p r e p a r e d at r o o m t e m p e r a t u r e . T h e s o l u t i o n i s f i l t e r e d and a l l o w e d t o s t a n d in i c e for s o m e t i m e in a c l o s e d E r l e n m e y e r f l a s k . T h e sulfur p r e - c i p i t a t e i s f i l t e r e d off and a g a i n c r y s t a l l i z e d s e v e r a l t i m e s in t h e s a m e m a n n e r . At t h e e n d of t h i s p r o c e d u r e , it i s p r e s s e d b e t w e e n f i l t e r p a p e r s t o r e m o v e a l l a d h e r i n g s o l v e n t , and i s finely p u l - v e r i z e d and d r i e d for a few h o u r s at 90 t o 1 0 0 ° C T h e p u r i f i e d p r o d u c t i s b r i g h t l i g h t - y e l l o w , and r e t a i n s only a v e r y w e a k o d o r of C S3.
H o w e v e r , R. F . B a c o n and R. F a n e l l i c l a i m t h a t t h e m a t e r i a l t h u s p u r i f i e d , a s w e l l a s a l l " c h e m i c a l l y p u r e " c o m m e r c i a l s u l f u r s , a r e s t i l l c o n t a m i n a t e d w i t h o r g a n i c s u b s t a n c e s ( p a r t i c u l a r l y liquid h y d r o c a r b o n s ) a s w e l l a s H3S , H3S x and a d s o r b e d g a s e s . T h e only m e t h o d c a p a b l e of r e m o v i n g t h e s e s t u b b o r n l y a d h e r i n g i m p u r i t i e s p r o c e e d s a s follows:
One k i l o g r a m of sulfur i s m e l t e d in a o n e - l i t e r , s h o r t - n e c k g l a s s f l a s k on an open f l a m e . D u r i n g t h i s o p e r a t i o n , t h e f l a s k i s c o v e r e d with a n i n v e r t e d f r i t t e d g l a s s c r u c i b l e . T h e t e m p e r a t u r e i s slowly i n c r e a s e d u n t i l t h e m a s s b e g i n s t o f o a m . A s s o o n a s g a s evolution s u b s i d e s , t h e liquid i s h e a t e d t o b o i l i n g , 5 g. of p u r e MgO i s a d d e d , and t h e s o l u t i o n i s b o i l e d for 3 - 4 h o u r s . It i s t h e n a l l o w e d t o s t a n d a t 125°C o v e r n i g h t . D u r i n g t h i s t i m e a b l a c k s l u d g e s e t t l e s t o t h e b o t t o m of t h e flask; t h i s i s r a p i d l y s e p a r a t e d , t o g e t h e r w i t h t h e MgO, by f i l t r a t i o n t h r o u g h a l a y e r of g l a s s w o o l . T h e c l e a r f i l t r a t e i s t r e a t e d four m o r e t i m e s in t h e s a m e m a n n e r , i . e . , e a c h t i m e adding 1% MgO, boiling for 2 5 - 3 0 h o u r s , and f i l t e r i n g t h r o u g h g l a s s w o o l . After a t o t a l t r e a t m e n t t i m e of 100-120 h o u r s , t h e f i l t r a t e i s
3 4 1
v e r y slowly c o o l e d . T h e f r e s h l y p u r i f i e d p r o d u c t i s c o m p l e t e l y g a s f r e e . After s t a n d i n g for s e v e r a l d a y s in a i r , it i s a g a i n p a r t i a l l y c o n t a m i n a t e d with g a s e s but c a n b e r e a d i l y d e g a s s e d by r e p e a t e d m e l t i n g and solidifying at a p r e s s u r e of 1 m m .
T h e p r o g r e s s of p u r i f i c a t i o n c a n be followed by o c c a s i o n a l l y t e s t i n g t h e c o n d e n s a t e c o l l e c t e d on t h e c o v e r i n g f r i t . T h u s , 3 g. of t h i s s u l f u r i s slowly h e a t e d t o b o i l i n g in a P y r e x t e s t t u b e (95 x 10 m m . ) (with p a r t i c u l a r c a r e b e i n g t a k e n t h a t t h e r e g i o n of t h e h i g h - v i s c o s i t y m e l t i s not t r a v e r s e d t o o quickly), boiled for 2 - 3 m i n u t e s , and a l l o w e d t o cool and solidify. No b l a c k s p o t s should a p p e a r at t h e l o w e r w a l l s of t h e g l a s s w h i c h a r e in c o n t a c t w i t h t h e f l a m e . T h e t e s t i s good to l e s s t h a n 1 0 "4% i m p u r i t i e s . B e f o r e t h e t e s t , t h e t e s t t u b e m u s t be r i n s e d w i t h hot c l e a n i n g s o l u t i o n , and d u r i n g t h e t e s t it m u s t b e p r o t e c t e d f r o m d u s t .
Von W a r t e n b e r g d e s c r i b e s a s i m p l e m e t h o d for obtaining S with a C content of l e s s t h a n 10 ~6%. T h i s p r o c e d u r e r e q u i r e s no s p e c i a l a t t e n t i o n and t a k e s p l a c e o v e r a p e r i o d of a few d a y s , A q u a r t z t u b e , e l e c t r i c a l l y h e a t e d t o 750°C, i s s u s p e n d e d in r e c r y s t a l l i z e d boiling S, t h u s c a u s i n g C S3 t o f o r m on it. When no f u r t h e r b l a c k m a t e r i a l p r e c i p i t a t e s on t h e t u b e , t h e sulfur i s d i s t i l l e d in v a c u u m .
A c c o r d i n g to Skj e r v e n , H2S m a y b e r e m o v e d f r o m t h i s c a r b o n - f r e e sulfur by t r e a t m e n t w i t h S 02.
PROPERTIES:
V e r y p u r e sulfur i s light y e l l o w and c o m p l e t e l y o d o r l e s s ; t h e m e l t t e n d s t o s u p e r c o o l ; t h e r e i s no r e s i d u e a f t e r b u r n i n g o r d i s t i l l i n g .
REFERENCES:
Abegg, Handbuch d e r a n o r g a n i s c h e n C h e m i e , Vol. IV, 1, p . 142.
J , H. Walton and E . L . W h i t f o r d , J . A m e r . C h e m . Soc. 4 5 , 601 (1923).
R. F . B a c o n and R. F a n e l l i , Ind. Eng. C h e m , 34, 1043 (1942).
H. von W a r t e n b e r g , Z . a n o r g . a l l g . C h e m . 2 5 1 , 166 (1943); 286, 243 (1956).
O. S k j e r v e n , Z . a n o r g . a l l g . C h e m . 2 9 1 , 325 (1957).
PLASTIC SULFUR
P l a s t i c sulfur i s f o r m e d by r a p i d cooling of m o l t e n s u l f u r . P u r e S i s h e a t e d to 2 5 0 - 3 5 0 C u n d e r a n i t r o g e n b l a n k e t . A t h i n s t r e a m of t h e m e l t i s t h e n p o u r e d into a c y l i n d r i c a l v e s s e l (at l e a s t 60 c m . high) w h i c h h a s a b o t t o m inlet a n d t o p o u t l e t for i c e - w a t e r flow. S t r a n d s of p l a s t i c s u l f u r c o l l e c t in t h e l o w e r p a r t w h i l e t h e f l o w e r s of s u l f u r f o r m i n g on t h e w a t e r s u r f a c e a r e c o n t i n u o u s l y flushed away.
7 . S U L F U R , S E L E N I U M , T E L L U R I U M 343
PROPERTIES:
Yellow, p l a s t i c , v i s c o e l a s t i c , a m o r p h o u s m a s s . T h e s t r a n d s c a n b e s t r e t c h e d out t o m a n y t i m e s t h e i r i n i t i a l l e n g t h , w h i c h c a u s e s p a r t i a l c r y s t a l l i z a t i o n . R e p e a t e d s t r e t c h i n g p r o d u c e s l o s s of e l a s t i c i t y . M o r e d e t a i l e d s t u d i e s h a v e b e e n m a d e by K. S a k u r a d a and H. E r b r i n g , K o l l o i d - Z . 7 2 , 129 (1935). I n s o l u b l e in w a t e r , p a r t i a l l y s o l u b l e in C S3.
REFERENCES:
Κ. H. M e y e r and Y. Go, Helv. C h i m . Acta 17, 1081 (1934).
R. Houwink, E l a s t i z i t a t , P l a s t i z i t a t und S t r u k t u r d e r M a t e r i e [ E l a s t i c i t y , P l a s t i c i t y and S t r u c t u r e of M a t e r i a l s ] , D r e s d e n and L e i p z i g , 1938, p . 3 5 3 .
H. S p e c k e r , K o l l o i d - Z . 1 2 5 , 106 (1952).
COLLOIDAL SULFUR SOLUTION
I. A v e r y s t a b l e m o n o d i s p e r s e d S s o l i s o b t a i n e d by m i x i n g a c i d i fied N a2S and N a3S 03 s o l u t i o n s of t h e p r o p e r c o n c e n t r a t i o n , followed by p e p t i z a t i o n .
Solutions of 7.2 g. of C . P . N a3S Oa · 7 H30 and 6.4 g. of C P . N a3S · 9 H30 , e a c h in 50 m l . of d i s t i l l e d H30 , a r e p r e p a r e d s e p a r a t e l y . T h e n 1.5 m l . of t h e N a3S 03 s o l u t i o n i s a d d e d with a p i p e t t e t o t h e N a3S s o l u t i o n . A m i x t u r e of 10 m l . of d i s t i l l e d H30 and 2.7 g. of c o n c e n t r a t e d H3S 04 i s t h e n added in d r o p s w i t h c o n s t a n t s t i r r i n g u p t o t h e point of i n c i p i e n t t u r b i d i t y (a t o t a l of 8 m l . i s n e e d e d ) . T h e n 5.5 g. of c o n c e n t r a t e d H3S 04 i s added to t h e r e m a i n i n g N a3S Oa s o l u t i o n and t h e N a3S s o l u t i o n i s p o u r e d in w i t h c o n s t a n t s t i r r i n g . T h e m i x t u r e i s a l l o w e d t o s t a n d for one h o u r in an E r l e n m e y e r f l a s k c o v e r e d w i t h a w a t c h g l a s s . It i s t h e n f i l t e r e d t h r o u g h a fluted funnel; t h e p r e c i p i t a t e i s w a s h e d f r o m t h e o u t s i d e of t h e f i l t e r w i t h about 100 m l . of H30 and i s p e p t i z e d on t h e f i l t e r w i t h 300 m l . of d i s t i l l e d w a t e r . About 5 t o 10 m l . of t h e y e l l o w i s h - w h i t e c o l l o i d a l sulfur s o l u t i o n r u n n i n g t h r o u g h t h e f i l t e r i s p o u r e d into 300 m l . of d i s t i l l e d H30 , f o r m i n g a beautiful, r e d d i s h o p a l e s c e n t s u l f u r s o l . After 24 h o u r s t h e s l i g h t d e p o s i t of solid w h i c h m a y h a v e f o r m e d i s f i l t e r e d off. T h e s o l i s t h e n s t a b l e for w e e k s . II. M o r e h i g h l y c o n c e n t r a t e d S s o l s m a y b e o b t a i n e d by p e p t i z a t i o n of finely d i v i d e d S p r e c i p i t a t e s in t h e p r e s e n c e of a p r o t e c t i v e c o l l o i d .
After t h e S p r e c i p i t a t e on t h e fluted funnel, p r e p a r e d a c c o r d i n g t o m e t h o d I, h a s b e e n w a s h e d , it i s m i x e d with sufficient 10% a g a r s o l u t i o n and d i l u t e NaOH t o r e a c h a c o n c e n t r a t i o n of 0.6% a g a r and 0.4% NaOH in t h e s o l p r o d u c t , r e l a t i v e to t h e weight of d r y s u l f u r . T h e m i x t u r e i s t h e n d e c a n t e d f r o m t h e i n s o l u b l e c o m p o n e n t s . T h e r e s u l t i n g sol i s v e r y s t a b l e .
REFERENCES:
I. A. J a n e k , K o l l o i d - Ze 64, 31 (1933).
II. B r i t i s h P a t . 4 1 1 241 (1934), IG. F a r b e n i n d u s t r i e . Hydroge n Sulfid e
H2S
T h e h y d r o g e n sulfide g a s p r e p a r e d in t h e l a b o r a t o r y f r o m F e S and d i l u t e HC1 i s g e n e r a l l y c o n t a m i n a t e d w i t h a c i d v a p o r s s u c h a s
H2 » C 02, A s H3, N2 and 02. T h e HC1 c a n be r e a d i l y r e m o v e d by s c r u b b i n g w i t h d i s t i l l e d w a t e r . T o r e m o v e A s H3, J a c o b s e n r e c o m m e n d s t h a t t h e g a s , p r e d r i e d w i t h C a C l2, b e p a s s e d t h r o u g h a U t u b e c o n t a i n i n g d r y iodine and g l a s s w o o l . T h e A s d e p o s i t s a s A s l3 and t h e s i m u l t a n e o u s l y f o r m e d HI i s t h e n s c r u b b e d out w i t h d i s t i l l e d w a t e r . After d r y i n g w i t h P205, t h e p e r m a n e n t g a s e s H2, N2 and 02 c a n b e r e m o v e d by c o n d e n s i n g t h e H2S in a t r a p c o o l e d w i t h D r y Ice f r e e z i n g m i x t u r e .
A c o n s i d e r a b l y p u r e r g a s i s obtained by t h e d e c o m p o s i t i o n of CaS ( p r e p a r e d by t h e Otto m e t h o d and p r e s s e d into c u b e s ) w i t h v e r y p u r e d i l u t e h y d r o c h l o r i c a c i d . T h e p r o d u c t g a s i s p a s s e d t h r o u g h a w a s h b o t t l e with d i s t i l l e d w a t e r , two w a s h b o t t l e s with KHS s o l u t i o n , a U t u b e w i t h C a C l2, and finally, into a t r a p c o o l e d with D r y Ice m i x t u r e . T h e H2S r e e v a p o r a t e d f r o m t h i s t r a p i s c o n t a m i n a t e d only w i t h a s m a l l quantity of C 02.
V e r y p u r e , a i r - and C 02- f r e e H2S c a n b e p r e p a r e d v i a t h e following p r o c e d u r e s :
I. HEATING OF CONCENTRATED Mg(HS)2 SOLUTION
A o n e - l i t e r r o u n d - b o t t o m f l a s k w i t h a t w o - h o l e r u b b e r s t o p p e r s e r v e s a s t h e g a s g e n e r a t o r . A s e p a r a t o r y funnel (250 m l . ) and a g a s outlet t u b e a r e p l a c e d in t h e s t o p e r . T h e n 250 m l . of s a t u r a t e d M g C l2 s o l u t i o n i s allowed t o flow in f r o m t h e s e p a r a t o r y funnel, followed by t h e s a m e quantity of H20 , and finally, by t h e s a m e v o l u m e of s a t u r a t e d NaHS s o l u t i o n . A u n i f o r m H2S s t r e a m i s g e n e r a t e d on slight h e a t i n g of t h e flask. T h e g a s i s f r e e of C 02. At t h e b e g i n n i n g of t h e r u n , t h e a p p a r a t u s i s flushed w i t h n a s c e n t H2S ( u s e a hood!) u n t i l a l l t h e a i r i s d i s p l a c e d . After t h i s , t h e g a s i s v e r y p u r e . It i s d r i e d o v e r P205 and g l a s s wool and c a n be u s e d f o r m o s t l a b o r a t o r y p u r p o s e s . T h e y i e l d , b a s e d on h y d r o s u l f i d e , i s about 80%.
Π. H2 + S = H2S
2.02 32.07 34.09
E s p e c i a l l y p u r e H2S c a n be o b t a i n e d by s y n t h e s i s f r o m t h e e l e m e n t s . T h e a p p a r a t u s i s shown in F i g . 1 5 3 . T h e f l a s k 7?, m a d e
7 . S U L F U R , S E L E N I U M , TELLURIUM 3 4 5
of h i g h - m e l t i n g g l a s s , i s c h a r g e d w i t h about 250 g. of c a r e f u l l y p u r i f i e d S ( s e e p . 341), T h e s i d e a r m r e a c t i o n t u b e r - δ , i n c l i n e d u p w a r d and having an i n t e r n a l d i a m e t e r of 2.5 c m . and a l e n g t h of 150 c m . , i s filled with p e a s i z e p u m i c e c h i p s for a length of 80 c m . T h e s e a r e p r e p u r i f i e d by b o i l i n g w i t h c o n c e n t r a t e d HC1, d i l u t e H2S 04 and t h e n H20 u n t i l t h e y show no C I " o r SOf" r e a c t i o n . T h e y a r e t h e n c a l c i n e d in a n i t r o g e n and t h e n in a h y d r o g e n s t r e a m . T h e p a r t of t h e t u b e c o n t a i n i n g t h e c h i p s i s e n c a s e d in f u r n a c e Ε and c a n b e h e a t e d t o 600°C. A l e a d c o o l i n g c o i l i s wound a r o u n d t h e m i d d l e of t h e t u b e s e c t i o n t h a t p r o t r u d e s f r o m t h e f u r n a c e . T h e t u b e o u t l e t i s c l o s e d off w i t h a t h i c k w a d of a b s o r b e n t c o t t o n a n d a o n e - h o l e r u b b e r s t o p p e r . F r o m t h e s t o p p e r , a t u b e l e a d s t o t h e p u r i f i c a t i o n and c o n d e n s a t i o n s e t u p ( w a s h b o t t l e 1 c o n t a i n s d i s t i l l e d w a t e r ; w a s h b o t t l e s 2 and 3 : d i s t i l l e d w a t e r and g l a s s c h i p s ; w a s h b o t t l e 4 : a b s o r b e n t c o t t o n ) .
F i g . 1 5 3 . P r e p a r a t i o n of h y d r o g e n s u l f i d e .
At t h e b e g i n n i n g of t h e r u n , c a r e f u l l y p u r i f i e d N2 i s i n t r o d u c e d a t Β u n t i l t h e a i r i s c o m p l e t e l y d i s p l a c e d f r o m t h e a p p a r a t u s . T h e n H2 i s a l l o w e d t o flow in at a r a t e of 8-9 l i t e r s / h o u r , w h i l e Ε i s s w i t c h e d on. W h e n t h e t e m p e r a t u r e h a s r i s e n t o 600°C, Ax i s c o o l e d w i t h liquid n i t r o g e n and t h e s u l f u r in Β i s h e a t e d t o b o i l i n g . T h e h y d r o g e n r e a c t s q u a n t i t a t i v e l y t o f o r m H2S . T h e h e a t input at Β should be r e g u l a t e d in s u c h a w a y t h a t no s u l f u r a c c u m u l a t e s in t h e s i d e a r m and a d e p o s i t of f l o w e r s of sulfur i s f o r m e d on t h e c o t t o n w a d only a f t e r s o m e t i m e h a s e l a p s e d . A l o o s e c o n d e n s a t e of long, shiny H2S c r y s t a l s p r e c i p i t a t e s i n ^l e It i s m e l t e d b r i e f l y f r o m t i m e t o t i m e in o r d e r to u t i l i z e t h e c o n d e n s e r v o l u m e c o m p l e t e l y a n d to a v o i d p l u g g i n g of t h e i n l e t s a n d o u t l e t s . W h e n A x i s full, s t o p c o c k a i s o p e n e d a n d Ax i s s e a l e d a t e . F o r p u r i f i c a t i o n t h e m a t e r i a l i s d i s t i l l e d f r o m A x into A 2 in a high v a c u u m by slowly h e a t i n g Ax and cooling As w i t h liquid n i t r o g e n (the i n t e r m e d i a t e U t u b e s a r e c o o l e d w i t h D r y Ice m i x t u r e ) . T h e f i r s t and l a s t p o r t i o n s of t h e d i s t i l l a t e a r e d i s c a r d e d . About 130 l i t e r s of H2S
a r e obtained in 18 h o u r s ; t h e i m p u r i t y c o n t e n t of t h e g a s i s l e s s t h a n 0.01%.
III. P u r e H2S , c o m p l e t e l y f r e e of h y d r o c h l o r i c a c i d , i s o b t a i n e d in a s i m p l e m a n n e r by d e c o m p o s i t i o n of a c o n c e n t r a t e d a q u e o u s s o l u t i o n of C P . N a2S * 9 H20 with 2 0 - 3 0 % p h o s p h o r i c a c i d ( C . P . ) . T h e a c i d i s allowed t o d r i p slowly f r o m a s e p a r a t o r y funnel into t h e s o d i u m sulfide s o l u t i o n , a n d t h e evolving g a s i s d r i e d o v e r C a C l2 and P205.
H y d r o g e n sulfide i s s t o r e d in liquid f o r m at low t e m p e r a t u r e o r in g a s o m e t e r s o v e r s a t u r a t e d NaCl s o l u t i o n . M e r c u r y m a y a l s o be u s e d a s s e a l i n g fluid when t h e g a s i s c o m p l e t e l y p u r e and d r y .
PROPERTIES:
C o l o r l e s s g a s with an u n p l e a s a n t o d o r r e m i n i s c e n t of r o t t e n e g g s ; highly t o x i c . R e d u c i n g a g e n t for m a n y s u b s t a n c e s ; for t h i s r e a s o n H2S c a n n o t b e d r i e d w i t h c o n c e n t r a t e d H2S 04.
M . p . —83°C, b . p . —59°C, c r i t . t. +100.5°C, c r i t . p . 98.0 a t m . g a g e ; d (b.p.) 0.9504; w t . p e r l i t e r 1.5392 g. Solubility at 760 m m . in 1 v o l u m e of H2O ( 0 ° C ) : 4 . 6 7 ; (20°C): 2 . 5 8 ; (100°C): 0.81 v o l u m e of H2S ; for f u r t h e r d e t a i l s , s e e D ' A n s - L a x (1949), T a b l e 332632 A, 7, p . 970; a l s o s o l u b l e in e t h a n o l .
In c r y s t a l l i n e H2S , t h e S a t o m s f o r m a f a c e - c e n t e r e d c u b i c l a t t i c e ; p r o b a b l y t y p e C I o r C 2 .
REFERENCES:
0 . J a c o b s e n . B e r . d t s c h . c h e m . G e s . 20, 1999 (1887).
A. K l e m e n c . Die Behandlung 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 . 1 8 0 .
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 . 6 8 .
I. E . G r i i n e r t . J . p r a k t . C h e m . 122, 1 (1929).
II. A. K l e m e n c and O. B a n k o w s k i . Z. a n o r g . a l l g . C h e m . 2 0 8 , 348 (1932).^
III. F . F e h e r , K. N a u s e d and H. W e b e r . Z . a n o r g . a l l g . C h e m . 290, 303 (1957).
Crud e Sulfan e HgSx
1. Na2S + y S = Na2Sx (x = y + 1)
Na2Sx + 2 HC1 = H2SX f 2 NaCl
An a q u e o u s solution of s o d i u m polysulfide w i t h t h e a p p r o x i - m a t e c o m p o s i t i o n N a2S5 # 5 s e r v e s a s t h e s t a r t i n g m a t e r i a l . It i s
7 . S U L F U R , SELENIUM , TELLURIUM 347 p r e p a r e d a s f o l l o w s : A t w o - l i t e r , r o u n d - b o t t o m , l o n g - n e c k f l a s k i s p l a c e d on a s t e a m b a t h and filled w i t h 500 g . of N a2S · 9 H20 , w h i c h i s t h e n h e a t e d w i t h 250 g . of p o w d e r e d S for t h r e e h o u r s . F r e q u e n t s h a k i n g i s n e c e s s a r y . T h e sulfide m e l t s in i t s w a t e r of c r y s t a l l i z a t i o n and d i s s o l v e s m o s t of t h e s u l f u r , w i t h t h e c o l o r of t h e m i x t u r e b e c o m i n g d e e p e r . T h e c o o l e d , d a r k r e d - b r o w n s o l u t i o n i s d i l u t e d w i t h 400 m l . of H20 . It i s t h e n r a p i d l y s u c t i o n - f i l t e r e d t o r e m o v e S r e s i d u e and o t h e r i m p u r i t i e s , and t h e f i l t r a t e i s d i l u t e d w i t h w a t e r t o one l i t e r .
Next, a f i v e - l i t e r f i l t r a t i o n j a r i s t h o r o u g h l y c o o l e d on t h e o u t s i d e w i t h a n i c e - s a l t m i x t u r e , and 2 k g . of finely c r u s h e d i c e and t w o l i t e r s of p u r e c o n c e n t r a t e d h y d r o c h l o r i c a c i d (d 1.19) a r e a d d e d one a f t e r t h e o t h e r . W h e n t h e a c i d r e a c h e s a t e m p e r a t u r e of
—15 t o —20°C, t h e a d d i t i o n of N a2Sx s o l u t i o n i s b e g u n . T h e s o l u t i o n (in a s e p a r a t o r y funnel) i s a d d e d w i t h t h o r o u g h s t i r r i n g o v e r a p e r i o d of 1-1.5 h o u r s . T h e s o l u t i o n b e c o m e s cloudy d u r i n g t h e r e a c t i o n b e c a u s e of t h e f o r m a t i o n of a m i l k y - w h i t e s u l f u r e m u l s i o n . T h e H2SX p r o d u c t s e t t l e s a t t h e b o t t o m a s a y e l l o w o i l . T h e a d d i t i o n r a t e should b e s o c o n t r o l l e d t h a t t h e t e m p e r a t u r e d o e s not r i s e a b o v e —10°C, if at a l l p o s s i b l e , and in no c a s e a b o v e —5°C;
o t h e r w i s e , d e c o m p o s i t i o n of t h e H2SX and e v o l u t i o n of H2S o c c u r s . A f t e r a l l t h e N a2Sx s o l u t i o n h a s b e e n a d d e d and t h e p r o d u c t oil h a s c o m p l e t e l y s e t t l e d , t h e m o t h e r l i q u o r i s d e c a n t e d and t h e oil i s w a s h e d in t h e f i l t r a t i o n j a r with 1 Ν HC1 a n d d e c a n t e d in a s e p a r a t o r y funnel. A s m a l l q u a n t i t y of P2Ob i s a d d e d t o t h e c r u d e s u l f a n e . T h e p r o d u c t h a s t h e a p p r o x i m a t e c o m p o s i t i o n H2S5 e 5; it c a n be s t o r e d in a c l o s e d g l a s s v e s s e l at 0°C f o r a f a i r l y long p e r i o d without c h a n g e . B e f o r e f u r t h e r u s e , t h e P 205 i s f i l t e r e d off t h r o u g h g l a s s w o o l . F r e s h l y p r e p a r e d H2SX should f o r m a c l e a r s o l u t i o n w i t h p u r e b e n z e n e . T h e y i e l d i s 260 g . (160 m l . ) of o i l , i . e . , 87% r e l a t i v e t o t h e s t a r t i n g s u l f u r .
If c r u d e s u l f a n e i s t o b e p r e p a r e d c o n t i n u o u s l y in f a i r l y l a r g e q u a n t i t i e s , t h e a p p a r a t u s d e s c r i b e d b y F . F e h e r a n d W. L a u e s h o u l d b e u s e d .
Use of sulfane for the preparation of H2S2 and H2S3: A c r u d e s u l f a n e w h i c h i s e s p e c i a l l y r i c h in H2S4 and i s t h e r e f o r e s u i t e d f o r t h e p r o d u c t i o n of t e t r a s u l f a n e i s p r e p a r e d in t h e following m a n n e r :
A s o l u t i o n of N a2S2 i s p r e p a r e d by h e a t i n g 480 g. of N a2S * 9 H20 , 64 g . of p o w d e r e d S and 500 m l . of H20 f o r t h r e e h o u r s in a t w o - l i t e r r o u n d - b o t t o m f l a s k on a s t e a m b a t h . T h e c o o l e d s o l u t i o n , s u c t i o n - f i l t e r e d t o r e m o v e S r e s i d u e s , i s t h e n d e c o m p o s e d in t h e m a n n e r d e s c r i b e d a b o v e , u s i n g f o u r l i t e r s of d i l u t e HC1. T h e y i e l d i s 32 m l . of c r u d e s u l f a n e h a v i n g t h e a p p r o x i m a t e c o m p o s i t i o n H2S4 e 5.
II. In g e n e r a l , e x c e s s s u l f a n e , H2S n , w h i c h a l s o a c t s a s a s o l v e n t , r e a c t s with a c h l o r o s u l f a n e SmC l2, p r o d u c i n g q u a n t i t a t i v e HC1
s e p a r a t i o n and c h a i n i n c r e a s e and f o r m i n g a h i g h e r sulfane H3Ss n+ m a c c o r d i n g t o t h e following s c h e m e :
H — S n — Η + C I — Sm— CI + H — S n — Η = H2S * n + m + 2HC1
E x c e s s H2Sn
T h e H2Ss n+ m , w h i c h i s f o r m e d a s an i n t e r m e d i a t e , r e a c t s in t u r n with t h e SmC l2. Again, HC1 i s s p l i t off. T h e f o r m a t i o n of a h o m o l o g o u s m i x t u r e of s u l f a n e s (= c r u d e s u l f a n e , H2SX) i s b a s e d on t h i s fact. (See a l s o p . 353).
T h e n u m b e r of m o l e s of r e a g e n t s , a and b, in t h e e q u a t i o n b e l o w g i v e s t h e a v e r a g e c o m p o s i t i o n χ and t h e quantity c of c r u d e sulfane f o r m e d when t h e quantity d of u n r e a c t e d s u l f a n e d i s t i l l e d off a f t e r t h e r e a c t i o n i s d e t e r m i n e d . T h e e q u a t i o n w a s d e r i v e d on t h e b a s i s of a s s u m p t i o n about t h e m o l e c u l a r d i s t r i b u t i o n o b t a i n e d in t h e c o n d e n s a t i o n of s u l f a n e s and h a l o s u l f a n e s ( F . F e h e r and W.
L a u e ) ; h o w e v e r , it h o l d s only for t h e a b o v e d e s c r i b e d r e a c t i o n s u n d e r t h e f u r t h e r r e s t r i c t i o n t h a t no o t h e r r e a c t i o n s t a k e p l a c e .
a H2Sn + b Sm Cl2 = c H2Sx + 2 bHCl + d H2Sn am + η (2a— b) b(n + m) . ., b \2 χ = , ; c ; d = a (1
a— b χ — η a /
I n t e r f e r i n g s i d e r e a c t i o n s w h i c h l e a d t o a h i g h e r S c o n t e n t of t h e c r u d e sulfane a r e f a v o r e d , a m o n g o t h e r t h i n g s , by t o o v i o l e n t a r e a c t i o n and by t o o s m a l l a sulfane e x c e s s . B e c a u s e of i t s e a s e of p r e p a r a t i o n , only H2S (n = 1) i s of i m p o r t a n c e a s a r a w m a t e r i a l for " c r u d e oil." T h e r e a g e n t s f o r t h e p r e p a r a t i o n of c h l o r o s u l f a n e a r e S C l2 ( m = l ) a n d S2C 12 ( m = 2). E l e m e n t a r y c h l o r i n e , w h i c h r e a c t s v e r y v i o l e n t l y , m a y a l s o b e u s e d . Since t h e p r o d u c t i s e i t h e r d i s t i l l e d o r c r a c k e d , t h e f o r m a t i o n of s i d e p r o d u c t s i s of n o p a r t i c u l a r i m p o r t a n c e .
F o r e x a m p l e , t h e r e a c t i o n of a 7 - m o l e e x c e s s of H2S with S C 12 y i e l d s a c r u d e oil w i t h t h e a p p r o x i m a t e c o m p o s i t i o n HaS4 5 and c o n t a i n i n g f a i r l y l a r g e q u a n t i t i e s of H2S3. With S2C 12, a c r u d e oil of t h e a p p r o x i m a t e c o m p o s i t i o n H2S5 # 2, c o n t a i n i n g a l a r g e a m o u n t of H2S4, i s o b t a i n e d . T h e s e r e a c t i o n s a r e c a r r i e d out in t h e s a m e a p p a r a t u s and in a m a n n e r a n a l o g o u s t o t h a t d e s c r i b e d f o r t h e p r e p a r a t i o n of t e t r a s u l f a n e (p. 354). T h e r e a c t i o n of liquid H2S w i t h C l2 y i e l d s m a i n l y HaS3 and H2S4, p l u s a s m a l l a m o u n t of H2S2.
T h e c h o i c e of t h e s e c o n d c o m p o n e n t in t h e r e a c t i o n with liquid H2S u s u a l l y d e p e n d s e i t h e r on t h e sulfane w h i c h i s t o b e d i s t i l l e d d i r e c t l y f r o m t h e c r u d e m i x t u r e o r , if c r a c k i n g i s t o follow t h e p r i m a r y r e a c t i o n , on t h e c o m p o s i t i o n of t h e sulfane m i x t u r e w h i c h i s b e s t s u i t e d for t h a t p r o c e s s .
7 . SULFUR , S E L E N I U M , TELLURIUM 349
SYNONYMS:
" C r u d e p e r h y d r o g e n s u l f i d e , " " c r u d e h y d r o g e n p e r s u l f i d e , "
" h y d r o g e n poly s u l f i d e , " o r j u s t " c r u d e o i l . " F o r t h e n o m e n - c l a t u r e of c h a i n c o m p o u n d s of s u l f u r , s e e F . F e h e r and W, L a u e , Z . N a t u r f o r s c h . 8b, 11 (1953).
PROPERTIES:
Yellow liquid r e s e m b l i n g olive oil, pungent o d o r of c a m p h o r and No definite m . p . ; s o l i d i f i e s in liquid a i r to f o r m a g l a s s y m a s s w h i c h s o f t e n s again on h e a t i n g o v e r a f a i r l y b r o a d t e m p e r a t u r e r a n g e . On h e a t i n g , c r a c k i n g t o l o w e r h y d r o g e n s u l f i d e s ( s e e H2S3 and H2S3) t a k e s p l a c e . G r a d u a l l y d e c o m p o s e d by w a t e r with evolution of H2S . S p o n t a n e o u s d e c o m p o s i t i o n i s c a u s e d by a l k a l i s and s o m e t i m e s even by t h e a l k a l i content of g l a s s . F o r t h i s r e a s o n , a l l v e s s e l s w h i c h c o m e in c o n t a c t with t h e p r o d u c t m u s t be
" n e u t r a l i z e d " b e f o r e h a n d by r i n s i n g with hot, c o n c e n t r a t e d h y d r o - c h l o r i c a c i d o r by t r e a t m e n t with g a s e o u s HC1. Soluble in C S2, C6H6 and C H C 13.
REFERENCES:
I. I. B l o c h and F . Hohn, B e r . d t s c h . c h e m . G e s . 4 1 , 1961 (1908);
F . F e h e r and M. B a u d l e r , Z . a n o r g . a l l g . C h e m . 2 5 8 , 147 (1949);
F . F e h e r and W. L a u e , Z . a n o r g . a l l g . C h e m . 288, 103 (1956).
II. F . F e h e r , W. L a u e and J . K r a e m e r , Z . a n o r g . a l l g . C h e m . 2 8 1 , 151 (1955); F . F e h e r and W. L a u e , Z . a n o r g . a l l g . C h e m . 287, 45 (1956); F . F e h e r and W. K r u s e , Z . a n o r g . a l l g . C h e m . 2 9 3 , 302 (1957).
Pure Sulfane s
Since s u l f a n e s a r e r e a d i l y d e c o m p o s e d by a l k a l i , m e t a l s , d u s t , c o r k , r o u g h s u r f a c e s a n d m o i s t u r e , a l l g l a s s v e s s e l s which c o m e in c o n t a c t with t h e m ( e v e n g l a s s wool) m u s t b e t h o r o u g h l y c l e a n e d , c a r e f u l l y d r i e d and s t o r e d in a d u s t - f r e e a t m o s p h e r e .
G l a s s v e s s e l s a r e r i n s e d with hot c l e a n i n g s o l u t i o n , t h e n with hot, p u r e , c o n c e n t r a t e d h y d r o c h l o r i c a c i d , and finally with d i s t i l l e d w a t e r . A p p a r a t u s c o n t a m i n a t e d with sulfur c a n be p r e c l e a n e d w i t h C S2 o r hot a m m o n i u m sulfide s o l u t i o n .
G r o u n d g l a s s c o n n e c t i o n s s h o u l d b e s e a l e d with s i l i c o n e g r e a s e . No N H3 g a s ( e . g . , f r o m b o t t l e s of c o n c e n t r a t e d a m m o n i a o r a m m o n i u m sulfide in t h e a r e a ) m a y b e p r e s e n t in t h e a t m o s p h e r e .
All r e a c t i o n s with s u l f a n e s m u s t be p r o t e c t e d f r o m m o i s t u r e , and p u r e s t a r t i n g m a t e r i a l s m u s t b e u s e d .
T h e s e p r e c a u t i o n s m u s t a l w a y s be v e r y c a r e f u l l y a d h e r e d t o w h e n w o r k i n g with s u l f a n e s , e v e n when t h i s i s not e x p r e s s l y p o i n t e d out in t h e p r e p a r a t i o n .
I. DISULFANE A N D TRISULFANE, H2S2, H2S3
Both of t h e s e h y d r o g e n sulfide c o m p o u n d s a r e f o r m e d by c r a c k i n g of c r u d e s u l f a n e , u s i n g t h e a p p a r a t u s shown in F i g . 154.
H2Sx = H2S2 + (x—2) S H2Sx = H2S3 + (x—3) S
Since t h e y i e l d s of H2S2 and H2S3 i m p r o v e when only s m a l l q u a n t i t i e s of H2SX a r e c r a c k e d at a t i m e , t h e p r o c e s s i s c a r r i e d out a s f o l l o w s . F i r s t , f l a s k a (300 m l . ) i s h e a t e d in a p a r a f f i n b a t h t o 110°C w h i l e t h e a p p a r a t u s i s e v a c u a t e d to 1 2 - 1 5 m m . T h e n 15 m l . of H2SX ( s e e p . 346 f o r p r e p a r a t i o n ) i s i n t r o d u c e d t h r o u g h d.
After a s h o r t t i m e t h e c o n d e n s e r s u r f a c e i s c o a t e d w i t h fine d r o p l e t s . T h e H2S3 c o l l e c t s s l o w l y but at a u n i f o r m r a t e in r e c e i v e r bt w h i c h i s at r o o m t e m p e r a t u r e , while t h e H2S2 i s c o n d e n s e d in t r a p ο, w h i c h i s c o o l e d with D r y I c e - m e t h a n o l m i x t u r e . T h e n t h e b a t h t e m p e r a t u r e at a i s slowly i n c r e a s e d t o 125°C o v e r a p e r i o d of 20 m i n u t e s . T h e f l a s k c o n t e n t s a r e c o o l e d t o 110°C and 15 m l . of H2SX i s a g a i n added t h r o u g h d. T h e 2 0 - m i n u t e h e a t i n g p r o c e d u r e i s r e p e a t e d . After two p o r t i o n s of H2S x h a v e b e e n c r a c k e d , t h e v a c u u m i s r e l e a s e d and 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 , p a s s i n g t h r o u g h t h e C a C l2 and s o d a - l i m e t u b e s . T h e g r o u n d g l a s s joint at a i s t h e n quickly d i s c o n n e c t e d , and t h e h o t , s t i l l liquid
78 °C
^20 soda lime CaCL2 F i g . 154. P r e p a r a t i o n of d i - and t r i s u l f a n e .
7 . S U L F U R , SELENIUM , TELLURIUM 3 5 1
r e s i d u e i s p o u r e d out, w h e r e u p o n it s o l i d i f i e s . After t h e g r o u n d g l a s s joint h a s b e e n r e s e a l e d , t h e c r a c k i n g i s c o n t i n u e d and t h e r e s i d u e i s a g a i n r e m o v e d a f t e r t w o 1 5 - m l . a d d i t i o n s of H3S x . About 25 m l . of H3S3 and 15 m l . of H3S3 a r e o b t a i n e d f r o m 120 m l , of f r e s h l y p r e p a r e d H3S x . With a g e d H3S x , t h e y i e l d of H3S3 i n c r e a s e s , w h i l e t h a t of H3S3 i s r e d u c e d . Both p r o d u c t s a r e n e a r l y p u r e ; at m o s t , e a c h i s c o n t a m i n a t e d by a s m a l l a m o u n t of t h e o t h e r .
U s e of t h e B l o c h and Hohn s u c t i o n d e v i c e t o r e m o v e t h e c r a c k i n g r e s i d u e i s not r e c o m m e n d e d s i n c e t h e r e s i d u e s o l i d i f i e s e a s i l y in t h e n a r r o w t u b e s and i s t h e n difficult t o r e m o v e .
F i g . 1 5 5 . D i s t i l l a t i o n of d i s u l f a n e .
T h e d i s u l f a n e i s f u r t h e r p u r i f i e d by d i s t i l l a t i o n in t h e a p p a r a t u s shown in F i g . 155.
T h e l o w - t e m p e r a t u r e c o l u m n h i s a L i e b i g c o n d e n s e r filled w i t h g l a s s R a s c h i g r i n g s . It i s c o o l e d by c i r c u l a t i n g m e t h a n o l f r o m a c o n s t a n t t e m p e r a t u r e b a t h t. T h e d i s t i l l a t i o n f l a s k d i s p l a c e d in a w a t e r b a t h w at r o o m t e m p e r a t u r e . T h e t r a p / for c o l l e c t i n g t h e p u r e d i s u l f a n e i s a t t a c h e d t o h with an a d a p t e r . T h e l i q u i d - n i t r o g e n - c o o l e d double t r a p I i s c o n n e c t e d t o a v a c u u m p u m p .
After t h e c r u d e d i s u l f a n e , w h i c h h a s b e e n d r i e d with P3Os and f i l t e r e d t h r o u g h g l a s s w o o l , i s c h a r g e d into t h e d i s t i l l a t i o n f l a s k d, t h e c o l u m n i s c o o l e d t o —15°C and t h e s y s t e m i s s l o w l y e v a c - u a t e d t o 15 m m . T h e f l a s k c o n t e n t s f o a m v i g o r o u s l y , r e l e a s i n g t h e d i s s o l v e d H3S . When t h e i n i t i a l f o a m i n g s u b s i d e s , c o n d e n s a t i o n of t h e p u r e d i s u l f a n e i s b e g u n by cooling / w i t h a D r y I c e - m e t h a n o l m i x t u r e . F u r t h e r d i s t i l l a t i o n d o e s not r e q u i r e any s p e c i a l a t t e n t i o n .
P u r i f i c a t i o n of 100 g. of d i s u l f a n e t a k e s about 1.5 h o u r s .
T h e t r i s u l f a n e i s f u r t h e r p u r i f i e d by d i s t i l l a t i o n in t h e a p p a r a t u s shown in F i g . 156.
T h e 5 0 0 - m l . f l a s k d9 i m m e r s e d in w a t e r b a t h iv, c a r r i e s a L i e b i g c o n d e n s e r kx filled w i t h g l a s s R a s c h i g r i n g s and a s p i r a l
F i g . 156. D i s t i l l a t i o n F i g . 157. P r e p a r a t i o n of t r i s u l f a n e . of t e t r a s u l f a n e .
c o n d e n s e r k2. T h e l a t t e r e x p a n d s at t h e b o t t o m to a t o r o i d , f r o m w h i c h an o u t l e t l e a d s to r e c e i v e r v. A h o r i z o n t a l c o n n e c t i n g t u b e l e a d s f r o m k2 to t r a p / . T h e l a t t e r i s followed by double t r a p I, c o o l e d with liquid n i t r o g e n , and t h i s in t u r n i s c o n n e c t e d to a h i g h - v a c u u m p u m p . E a c h c o n d e n s e r i s p r o v i d e d with i t s own c o n s t a n t - t e m p e r a t u r e c i r c u l a t i o n s y s t e m . T h e r u n i s s t a r t e d by adjusting t h e t e m p e r a t u r e in kx to 42°C. Then flask d i s filled with t h e c r u d e t r i s u l f a n e and a t t a c h e d to t h e a p p a r a t u s . T r a p / i s c o o l e d with Dry I c e - m e t h a n o l and t h e s y s t e m i s slowly e v a c u a t e d . When a p r e s s u r e of 1.5 m m . i s r e a c h e d , k2 and ν a r e c o o l e d with i c e w a t e r and w a t e r b a t h w i s h e a t e d to 52°C. T h e d i s t i l l a t i o n now p r o c e e d s without f u r t h e r a t t e n t i o n ; H2S3 c o n d e n s e s in v. T h e m o r e v o l a t i l e o i l s c o n d e n s e in / and t h e l e s s v o l a t i l e c o m p o n e n t s in kl9 f r o m w h i c h they flow b a c k into f l a s k d. T h e t e m p e r a t u r e s in kl9 k2 and w m u s t b e c o n s t a n t d u r i n g t h e r u n . T h e p u r e d i s t i l l a t e g e n e r a l l y h a s t h e c o m p o s i t i o n H2S3 i 0 0_3 e 0 3.
E q u i p m e n t for t h e c o n t i n u o u s p r e p a r a t i o n of l a r g e r q u a n t i t i e s of H2S2 and H2S3 i s d e s c r i b e d by F . F e h e r and M. B a u d l e r , Z.
a n o r g . C h e m . 2 5 3 , 170 (1947); 254, 251 (1947); and F . F e h e r , W.
L a u e and G. W i n k h a u s , Z. a n o r g . a l l g . C h e m . 2 8 8 , 113 (1956). T h i s
7 . S U L F U R , S E L E N I U M , TELLURIUM 353 e q u i p m e n t m a y a l s o b e u s e d t o p r e p a r e d i s u l f a n e in y i e l d s g r e a t e r t h a n t h o s e d e s c r i b e d a b o v e .
II. TETRASULFANE, H2S4
T e t r a s u l f a n e i s o b t a i n e d f r o m c r u d e sulfane in t h e a p p a r a t u s shown in F i g . 157.
T h e modified U t z i n g e r t u b e h9 t h e l o w e r p a r t of w h i c h i s f l a t t e n e d t o i n c r e a s e t h e v a p o r i z a t i o n s u r f a c e a s m u c h a s p o s s i b l e ( s e e c r o s s s e c t i o n ) , i s s u r r o u n d e d by a h e a t i n g j a c k e t and c a r r i e s a s e p a r a t o r y funnel t and a 5 0 0 - m l . f l a s k r . T h e a t t a c h e d c o n d e n s e r kx and the s p i r a l c o n d e n s e r k2 (which i s i d e n t i c a l to t h a t u s e d in t r i s u l f a n e p u r i f i c a t i o n and h a s a t o r o i d a i e x p a n s i o n and an o u t l e t to t h e r e c e i v e r v) a r e p r o v i d e d w i t h s e p a r a t e c o n s t a n t - t e m p e r a t u r e c i r c u l a t i n g s y s t e m s . Again, c o n d e n s e r k2 i s c o n n e c t e d t o t r a p / , w h i c h i s i m m e r s e d in a D r y I c e - m e t h a n o l m i x t u r e . T r a p / a d j o i n s double t r a p / , c o o l e d with liquid n i t r o g e n , w h i c h i s c o n n e c t e d to a h i g h - v a c u u m p u m p . T h e c o n n e c t i n g s e c t i o n s of t h e c o n d e n s e r s a r e c o v e r e d w i t h a s b e s t o s i n s u l a t i o n ^ a n d £3.
T h e s y s t e m i s e v a c u a t e d u n t i l a p r e s s u r e of 10 ~3 m m . i s a t t a i n e d . T u b e h i s h e a t e d t o 75°C, kx t o 50°C, and ft3 and t h e w a t e r b a t h t o 15°C. T h e n c r u d e oil of c o m p o s i t i o n H3S4 - 5 _B e 0 ( p r e p a r a t i o n on p . 346) i s allowed t o d r i p s l o w l y f r o m t h e s e p a r a t i n g funnel t into t h e t u b e h. T h e v o l a t i l e c o m p o n e n t s of t h e oil d i s t i l l off w h i l e t h e r e s i d u e c o l l e c t s in r . C o n d e n s e r k2 s e p a r a t e s t h e t e t r a s u l f a n e f r o m t h e l i g h t e r and h e a v i e r c o m p o n e n t s of t h e d i s t i l l a t e . T h e p r o d u c t i s c o l l e c t e d in v. An H3S3- H3S3 m i x t u r e c o l l e c t s i n / w h i l e t h e h i g h e r - b o i l i n g f r a c t i o n s flow f r o m 7r1 into r .
III. TETRA-, ΡΕΝΤΑ-, HEXA-, HEPTA-and OCTASULFANES H2S4, H2S5, H2S6, H2S7, H>S8
(a — 2 ) H2Sn+ H—Sn- H + C I —S m — CI + H — Sn—Η = H2S2 n+ m + 2HC1 + (a —2) H2Sn
η = 1, 2.
m = 1, 2, 3, 4, 5, 6.
In g e n e r a l , e x c e s s s u l f a n e H3Sn r e a c t s w i t h a c h l o r o s u l f a n e S m C l3, s p l i t t i n g off HC1 q u a n t i t a t i v e l y and p o l y m e r i z i n g t o f o r m a h o m o l o g o u s m i x t u r e of c h a i n s u l f a n e s . T h e f o r m a t i o n of s u c h a m i x t u r e i s p r e d i c a t e d on t h e fact t h a t t h e p r o d u c t of t h e p r i m a r y r e a c t i o n r e a c t s f u r t h e r w i t h t h e c h l o r o s u l f a n e ( c o m p a r e p . 348).
If, h o w e v e r , a v e r y l a r g e e x c e s s of t h e H3S n c o m p o n e n t (a) i s u s e d , individual s u l f a n e s c a n b e o b t a i n e d v i a d i r e c t s y n t h e s i s . In t h i s c a s e , t h e r a t e of f o r m a t i o n of t h e sulfane i s s o m u c h l a r g e r t h a n t h a t of t h e h o m o l o g s t h a t it i s r e a c t i o n - c o n t r o l l i n g . T h e e x c e s s of t h e s u l f a n e , (a - 2 ) H3Sn, i s d i s t i l l e d off a f t e r t h e r e a c t i o n . U s i n g t h i s p r i n c i p l e , it i s p o s s i b l e t o o b t a i n , w i t h a p p r o p r i a t e c h l o r o -
s u l f a n e s , a l m o s t p u r e H2S4, H3S5, H2S6, H2S7 and H2S8. T h e p r e p a r a t i v e p r o c e d u r e s for all t h e s e p r o d u c t s a r e a n a l o g o u s , t h e r e a c t i o n c o n d i t i o n s m i l d , and t h e p r o d u c t s a l m o s t u n c o n t a m i n a t e d with e a c h o t h e r .
T h e s e s u l f a n e s a r e g e n e r a l l y b e s t p r e p a r e d f r o m t h e following r e a c t a n t s :
D e s i r e d Sulfane c o m p o n e n t C h l o r o s u l f a n e
sulfane c o m p o n e n t
H2S4 H2S s2c i2
H2 S2 S C 12
o r H2S S 3 C I 2
H2 S6 H2S2 s2c i3
H2S7 H2S S5C 12
o r H2S2 s3c i2
H2SQ H2S2 s ^ c i2
A s an e x a m p l e of t h e p r o c e d u r e and t h e r a t i o s of t h e r e a c t a n t s u s e d , t h e p r e p a r a t i o n of t e t r a - and p e n t a s u l f a n e a r e d e s c r i b e d . a) T E T R A S U L F A N E , H2S,
H — S — Η + C I — S— CI + H I — S — Η = H2S4 + 2HC1 34.08 135.05 34.08 130.28 72.93
E x c e s s H2S
T h e r e a c t i o n i s c a r r i e d out in a 5 0 0 - m l . , f o u r - n e c k f l a s k , p r o v i d e d w i t h one m a l e and t h r e e f e m a l e g r o u n d g l a s s c o n n e c t i o n s for P205 d r y i n g t u b e , s e p a r a t i n g funnel, l o w - t e m p e r a t u r e t h e r m o m e t e r , and a m e r c u r y s e a l s t i r r e r . T h e p r o d u c t i s p o u r e d out t h r o u g h t h e n e c k with t h e m a l e c o n n e c t i o n .
T o p r e p a r e t h e H2S , a c o n c e n t r a t e d a q u e o u s solution of C P . N a2S - 9 H30 (1800 g.) i s d e c o m p o s e d with C P . 2 5 % H3P 04 (3400 g.) ( c o m p a r e p . 346) and t h e g a s i s p a s s e d t h r o u g h C a C l3 and P305 d r y i n g t u b e s into a c o o l e d t r a p ( m e t h a n o l - D r y Ice) w h e r e about 150 m l . of H2S i s c o n d e n s e d . F r o m t h i s t r a p , t h e H2S i s d i s t i l l e d into t h e r e a c t i o n flask, p a s s i n g t h r o u g h t h e C a C l2 and P205 d r y i n g t u b e s . T h e r e a c t i o n f l a s k i s i m m e r s e d in a D e w a r f l a s k c o n t a i n i n g D r y I c e - m e t h a n o l m i x t u r e and t h e g a s i s t h u s liquefied.
About 20 g. of d i c h l o r o d i s u l f a n e (about 0.15 m o l e ) i s c a r e f u l l y added f r o m a s e p a r a t o r y funnel. T h e addition t e m p e r a t u r e i s —80°
C, s t i r r i n g i s e m p l o y e d , and t h e d i c h l o r o s u l f a n e i s a d d e d d r o p - b y - d r o p o v e r a p e r i o d of two h o u r s . It i s a d v i s a b l e t o p r e c o o l t h e c h l o r o s u l f a n e . T h u s , a b e n t c a p i l l a r y i s a t t a c h e d t o t h e outlet t u b e of t h e s e p a r a t o r y funnel. T h i s c a p i l l a r y i s i m m e r s e d in t h e liquid H2S and t h e n d i s c h a r g e s above t h e s u r f a c e of t h e H2S . T h e r e a c t i o n
7 . S U L F U R , SELENIUM » TELLURIUM 355 i s c o m p l e t e a f t e r about 12 h o u r s , when t h e r e a c t i o n m i x t u r e h a s b e c o m e c o l o r l e s s . T h e e x c e s s H2S , c o n t a m i n a t e d w i t h HC1, i s s l o w l y e v a p o r a t e d by r e m o v i n g t h e D e w a r f l a s k . T h e l a s t t r a c e s of H2S a r e r e m o v e d by b r i e f l y a p p l y i n g a n a s p i r a t o r v a c u u m . C l e a r , a l m o s t p u r e t e t r a s u l f a n e r e m a i n s in t h e f l a s k . Since H2S i s highly t o x i c , t h e p r e p a r a t i o n m u s t b e c a r r i e d out u n d e r a good hood.
b) PENTASULFANE, H2S5 Η — S2— Η +
6.15
Cl|—S—|C1 102.98
+ H — S
66,15
-H = H2S5 + 2HC1 162.35 72.93
E x c e s s H2S2
T h e r e a c t i o n flask ( d e s c r i b e d in t h e p r e p a r a t i o n of t e t r a s u l f a n e ; s e e above) c o n t a i n i n g 100 g. H2S2 i s c o o l e d w i t h D r y I e e - m e t h a n o l t o —60 t o —65°C in a D e w a r f l a s k . F r o m t h e s e p a r a t o r y funnel, 10 g. of S C 12 (about 0.1 m o l e ) i s a l l o w e d t o d r i p in slowly (with s t i r r i n g ) in s u c h a way t h a t t h e t e m p e r a t u r e of t h e m i x t u r e d o e s not r i s e a b o v e —55°C. In c o n t r a s t t o t h e p r e p a r a t i o n of t e t r a s u l f a n e , t h e u s e of a b e n t o u t l e t c a p i l l a r y i s not r e c o m m e n d e d , s i n c e it p l u g s e a s i l y . T h e D e w a r f l a s k i s r e m o v e d 15 m i n u t e s a f t e r t h e c o m p l e t i o n of t h e d r o p w i s e a d d i t i o n . When t h e m i x t u r e h a s w a r m e d t o 0°C, t h e t e m p e r a t u r e i s h e l d c o n s t a n t u n t i l t h e evolution of HC1 h a s , f o r all p r a c t i c a l p u r p o s e s , e n d e d ; t h e m i x t u r e i s t h e n s t i r r e d for a n o t h e r 0.5 h o u r a t r o o m t e m p e r a t u r e . T h e t o t a l r e a c t i o n t i m e i s 1.5 h o u r s .
T h e c l e a r m i x t u r e i s p o u r e d into a 2 5 0 - m l . , t w o - n e c k f l a s k . One n e c k of t h i s f l a s k , t h e one c o n n e c t e d t o a r e c e i v i n g t r a p , i s s h a p e d a s shown in F i g . 158. T h i s i n t r i c a t e s h a p e i s n e c e s s a r y s i n c e t h e H2S2 t o be e v a p o r a t e d t e n d s t o s u p e r h e a t and s p l a s h . T h e o t h e r n e c k i s a m a l e g r o u n d g l a s s p i e c e and i s u s e d for p o u r i n g out t h e p r o d u c t . M o s t of t h e H2S2 i s r e m o v e d in a v a c u u m of 15 m m . , t h e r e m a i n d e r in high v a c u u m (about 1 0 ~3 t o 10 ~4 m m . ) . T h e p r o d u c t i s a l s o b r i e f l y h e a t e d t o 30 t o 40°C d u r i n g t h e l a s t s t a g e of H2S2 r e m o v a l . T h e g e n e r a l l y quite c l e a r g r e e n i s h - y e l l o w t o y e l l o w r e s i d u e r e p r e s e n t s t h e d e s i r e d p r o d u c t , w h i c h i s quite p u r e .
F i g . 158. E v a p o r a t i o n of e x c e s s d i s u l f a n e .
PROPERTIES:
H2S2:
F o r m u l a weight 6 6 . 1 5 . M . p . - 8 9 . 6 ° C , b . p . 70.7°C; d. (20°C) 1.334.
Light y e l l o w l i q u i d .
H3S3:
F o r m u l a weight 9 8 . 2 1 . M . p . - 5 2 t o - 5 4 ° C ; d (20°C) 1.491. On h e a t i n g , c r a c k i n g t o H2S2, H2S2 and S o c c u r s . L i g h t y e l l o w liquid of s o m e w h a t d e e p e r c o l o r t h a n H2S2. Both H2S2 and H2S3 h a v e a pungent o d o r of c a m p h o r and S2C 12; the v a p o r s a r e i r r i t a t i n g t o t h e e y e s and m u c o u s m e m b r a n e s . On p r o l o n g e d s t a n d i n g , both a r e c o n v e r t e d to h o m o l o g s r i c h e r in s u l f u r , giving off H2S , With w a t e r t h e y d e c o m p o s e with evolution of H2S and p r e c i p i t a t i o n of S.
Soluble in C S2, C6H6 and C H C 13. H2S4:
F o r m u l a w e i g h t 1 3 0 . 2 8 . B r i g h t l i g h t - y e l l o w liquid s i m i l a r to o l i v e o i l , pungent o d o r . S o m e w h a t l e s s e a s i l y d e c o m p o s e d t h a n H2S2 and H2S3; l i k e t h e s e , it i s c o n v e r t e d on p r o l o n g e d s t a n d i n g into h o m o l o g s r i c h e r in s u l f u r . No definite m e l t i n g point; s o l i d i f i e s at about —85°C t o a w h i t e , g l a s s y m a s s w h i c h g r a d u a l l y softens o v e r a f a i r l y w i d e t e m p e r a t u r e r a n g e when h e a t e d . C r a c k e d by h e a t i n g to l o w e r h y d r o g e n s u l f i d e s , p a r t i c u l a r l y H2S . d (20°C) 1.582.
H2S5:
F o r m u l a weight 162.35. d (20°C) 1.644.
H2S6:
F o r m u l a w e i g h t 1 9 4 . 4 1 . d (20°C) 1.688.
H2S7:
F o r m u l a w e i g h t 2 2 6 . 4 8 . d (20°C) 1.721.
H2SQ:
F o r m u l a weight 258.54. d (20°C) 1.747.
T h e p r o p e r t i e s of t h e h i g h e r s u l f a n e s ( f r o m H2S5 up) a r e s i m i l a r t o t h o s e of t h e l o w e r h o m o l o g s . T h e y a r e g r e e n i s h - y e l l o w l i q u i d s , c h a n g i n g t o a d e e p e r y e l l o w with i n c r e a s i n g c h a i n l e n g t h . At 0°C, t h e s u b s t a n c e s a r e s t a b l e for s e v e r a l d a y s if t h e y a r e p r o t e c t e d f r o m c o n t a c t with a i r .
REFERENCES:
I. I. Bloch and F . Hohn, B e r . d t s c h . c h e m . G e s . 41_, 1 9 7 1 , 1975 (1908); F . F e h e r , W. L a u e and G. W i n k h a u s , Z . a n o r g . a l l g . C h e m . 2 8 8 , 113 (1956).
7 . S U L F U R , SELENIUM , TELLURIUM 357 II. F . F e h e r and M. B a u d l e r , Z. a n o r g . C h e m . 254, 289 (1947);
F . F e h e r , W. L a u e and G . W i n k h a u s , Z. a n o r g . a l l g . C h e m . 2 8 8 , 113 (1956).
III. F . F e h e r and L . M e y e r , Z . N a t u r f o r s c h . l i b , 605 (1956); F . F e h e r and G. W i n k h a u s , Z . a n o r g . a l l g . C h e m . 2 8 8 , 123 (1956);
F . F e h e r and W. K r u s e , Z . a n o r g . a l l g . C h e m . 2 9 3 , 302 (1957).
Ammoniu m Hydroge n Sulfid e NH4HS
N H3 + H2S = N H4H S 17.03 34.08 51,11
C a r e f u l l y d r i e d N H3 and H2S a r e a l t e r n a t e l y a d d e d t o a n E r l e n - m e y e r f l a s k c o n t a i n i n g a n h y d r o u s e t h e r at 0°C; t h e f l a s k m u s t b e c a r e f u l l y p r o t e c t e d f r o m m o i s t u r e . W h i t e c r y s t a l s of p u r e N H4H S p r e c i p i t a t e . T h e s e r e a d i l y d e c o m p o s e a g a i n at r o o m t e m p e r a t u r e into N H3 and H2S and m u s t t h e r e f o r e be quickly s u c t i o n - f i l t e r e d and f r e e d of a d h e r i n g e t h e r by p r e s s i n g b e t w e e n f i l t e r p a p e r s . W h e n s e a l e d in g l a s s a m p o u l e s , N H4H S i s s t a b l e for s o m e t i m e .
PROPERTIES:
W h i t e , n e e d l e - s h a p e d c r y s t a l s ; e a s i l y d e c o m p o s e d ; d i s s o c i a t i o n p r e s s u r e at r o o m t e m p e r a t u r e about 350 m m . d 1.17.
R e a d i l y s o l u b l e in w a t e r and e t h a n o l , f o r m i n g c o l o r l e s s s o l u t i o n s w h i c h r a p i d l y y e l l o w in a i r ; i n s o l u b l e in e t h e r and b e n z e n e .
T e t r a g o n a l c r y s t a l s , s p a c e g r o u p Djh.
REFERENCE:
J . S. T h o m a s and R. W. R i d i n g , J . C h e m . Soc. (London) 1 2 3 , 1181 (1923).
Sodiu m Hydroge n Sulfid e NaHS
C2H5O N a + H2S = NaHS + Q H5O H 68.06 34.08 56.07 46.07
C a r e f u l l y d e h y d r a t e d C2H5O H (20 m l . ) and s m a l l , b r i g h t p i e c e s of Na (2 g.) a r e p l a c e d in a 1 5 0 - m l . g l a s s f l a s k e q u i p p e d w i t h a r e - flux c o n d e n s e r and an a d a p t e r , c l o s e d a t f i r s t , for i n t r o d u c i n g a g a s
inlet t u b e . A d r y i n g t u b e on t h e r e f l u x c o n d e n s e r p r e v e n t s p e n e t r a - t i o n of a t m o s p h e r i c m o i s t u r e . When t h e e t h o x i d e b e g i n s t o s e p a r a t e , j u s t enough a d d i t i o n a l CsH5O H i s added t o k e e p a l l s o l u t e in solution at r o o m t e m p e r a t u r e . A t o t a l of about 40 m l . of C2HBO H i s n e e d e d . T h e n a g l a s s t u b e , r e a c h i n g t o t h e b o t t o m of t h e f l a s k , i s i n t r o d u c e d t h r o u g h t h e a d a p t e r and s e a l e d in t i g h t l y w i t h a r u b b e r s t o p p e r o r a p i e c e of h o s e . A f a s t s t r e a m of p u r e , c a r e - fully d r i e d H2S ( s e e p . 344 ff.) i s i n t r o d u c e d t h r o u g h t h i s t u b e into t h e s o l u t i o n . After a few m i n u t e s , an a b u n d a n t , fine c r y s t a l l i n e p r e c i p i t a t e of s l i g h t l y i m p u r e NaHS s e p a r a t e s out. T h e s o l u t i o n i s s a t u r a t e d w i t h H2S and quickly s u c t i o n - f i l t e r e d . T h e f i l t r a t e i s t r a n s f e r r e d into a d r y E r l e n m e y e r f l a s k and 50 m l . of p u r e a b s o - l u t e e t h e r i s added. A d e n s e , p u r e w h i t e p r e c i p i t a t e of NaHS s e p a r a t e s i m m e d i a t e l y . It i s a l l o w e d t o s e t t l e in t h e s t o p p e r e d f l a s k , and s m a l l p o r t i o n s of e t h e r a r e a d d e d a s long a s c r y s t a l s c o n t i n u e t o f o r m in t h e s u p e r n a t a n t liquid. In a l l , about 110 m l . of e t h e r i s r e q u i r e d for t h e p r e c i p i t a t i o n . T h e p r e c i p i t a t e i s quickly s u c t i o n - f i l t e r e d , w a s h e d with a b s o l u t e e t h e r , and t r a n s f e r r e d t o a v a c u u m d e s i c c a t o r . T h e y i e l d i s 4,3 g. of NaHS. T h e p r o d u c t i s a l m o s t a n a l y t i c a l l y p u r e . R e d i s s o l u t i o n in a b s o l u t e C2H5O H and r e p r e c i p i t a t i o n with e t h e r r e a d i l y y i e l d s a c o m p l e t e l y p u r e s u b s t a n c e .
PROPERTIES:
W h i t e , g r a n u l a r c r y s t a l l i n e p o w d e r ; v e r y h y g r o s c o p i c . T u r n s y e l l o w on h e a t i n g in d r y a i r , o r a n g e at h i g h e r t e m p e r a t u r e s ; m e l t s t o a b l a c k liquid at about 350°C. d 1.79.
V e r y soluble in w a t e r ; m o d e r a t e l y s o l u b l e in C2H5O H . P u r e NaHS d i s s o l v e s in h y d r o c h l o r i c a c i d w i t h v i g o r o u s evolution of H2S t o f o r m a c l e a r solution. Aged p r o d u c t s g i v e a w e a k l y y e l l o w i s h , o p a l e s c e n t s o l u t i o n .
R h o m b o h e d r a l l y d i s t o r t e d NaCl s t r u c t u r e , s p a c e g r o u p D ^d.
REFERENCES:
A. R u l e , J . C h e m . S o c (London) 99, 558 (1911).
W. T e i c h e r t and W, K l e m m , Z . a n o r g . a l l g . C h e m . 2 4 3 , 86 (1939).
Sodiu m Sulfid e Na2S
I. 2 Na + S = Na2S
45.99 32,07 78.06
T h e r e a c t i o n i s c a r r i e d out in liquid a m m o n i a u s i n g t h e a p p a r a t u s of F i g . 159.
