Sept.. r g i
j
T H E J O l - R S A L O F I S D L ' S T R I A L .4-IrD ELVGIAVltEERISG C H E M I S T R Y
which is fitted a double t u b e . T h e outer t u b e is connected b y a s h o r t T t u b e , F , bent d o w n w a r d a n d fitted with a r u b b e r t u b e b y m e a n s of lvhich t h e operator sucks u p solution t o fill t h e b u r e t t e . T h e inner or
E
\
01-erflow t u b e G is fused i n t o t h e outer a n d bends d o w n w a r d , connecting by m e a n s of a short r u b b e r t u b e , with a small glass t u b e , H . T h i s t u b e extends d o m i t h e back of t h e b u r e t t e a n d joins, b y m e a n s of a n o t h e r short rubber t u b e , with t h e t u b e C. T h e overflow t u b e G m a y be a d j u s t e d b y sliding u p or d o w n in t h e cork E so t h a t t h e lower e n d of it is o n t h e s a m e level as t h e zero m a r k on t h e b u r e t t e . It is seen t h a t when t h e liquid a b o v e t h e zero m a r k on t h e b u r e t t e is allowed t o siphon back it will drain off all t h e liquid above t h e zero m a r k . I n order t o fill t h e b u r e t t e , t h e operator opens t h e pinch-cock J a n d sucks t h r o u g h t h e r u b b e r t u b e K till t h e liquid is a b o v e t h e zero m a r k o n t h e b u r e t t e . He t h e n allows t h e excess t o automatically siphon back t h r o u g h t h e overflow t u b e i n t o t h e main supply. I n s t e a d of filling t h e b u r e t t e b y suction, a rubber bulb m a y be a t t a c h e d t o t h e bottle so t h a t t h e b u r e t t e c a n be filled b y air pressure. F o r small supply bottles this m e t h o d is excellent b u t for larger ones it is not so satisfactory. 6358 ELLISA v s r u c , CHICAGO,1~1.1~015 ~
~~. .___
A KJELDAHL DISTILLATION APPARATUS By J. M. PICKEL Received March 6, 1915
M r . Holmes describes w h a t is evidently a n excellent f o r m of Kjeldahl distillation a p p a r a t u s . ' We h a v e 1
THISJOT:RSAL. 6 ,1914). 1010.
i87
been using for eight or t e n years in t h e laboratory of t h e S o r t h Carolina D e p a r t m e n t of Agriculture a distillation a p p a r a t u s of t h e writer's designing, which xvould seem t o be simpler, more flexible a n d less costly t h a n t h a t of XIr. Holmes'. This a p p a r a t u s has t h e following features, some of which a r e , so f a r as k n o n n t o t h e writer. distincti1-e: I--The connecting bulbs a n d condensing t u l m are in one piece. t h u s eliminating annoying rubbcr connections. ( I n t h e case of a copper still. t h e whcl.1~ t h i n g is in one piece.) a-The condensing t u b e s are not clamped, s c r e ~ e d or a t t a c h e d , in a n y way, t o other p a r t s of t h e npparntus: a n d n o t enclosed within a n y other p a r t of the a p p a r a t u s . ( T o be sure, during distillation. there is. connection with flask a n d receiver.) 3-111 consequence of items I a n d 2 , a n y condenser c a n , without interfering with a n y other condenser, be instantly removed and a n o t h e r dropped i n t o its place; a n y condenser can. therefore, without d i s t u r b ing its neighbors, be repaired, or flushed o u t with n-:,ter
FIG.
I-BACK VIEW
OF
KJIXDAIIL DISTII.LIN(: APPIKPTI'.
under a t a p , or air forced into it under water ( w i t h x bicycle p u m p , for example), this l a t t e r \operation dis-closing b y air bubbles even t h e tiniest leak (all of o u r condensers are t h u s tested when first p u t i n t o comniission a n d a t suitable intervals t h e r e a f t e r ) . 4-The condensers adjust themselves autoniaiicnlly t o distilling flasks of different lengths. 5-In case one cares t o set or h a n g t h e app::ra:us against a mall. t h u s throwing distilling flasks a n d re-. ceil-ers on one a n d t h e s a m e side, t h e condensers a r c easily adjusted t o t h a t a r r a n g e m e n t ; b u t t h e recei\,ers are placed a b o e e , not b e l o w , t h e distilling flasks. 6--The distilling flasks, their support a n d h e a t e r s (Bunsen burners) are suspended over a t r o u g h . 7 in conscquencc of arrangement 5 and 6 , i f . d u r i n g distillation, a distilling flask lireaks, as not inirc-. q u e n t l y happens. t h e contents of it drop. n o t o n t h e t a b l e , nor on or i n t o a receiver. b u t i n t o t h e trough. which can be easily flushed out with water. S--Regurgitation of liquid from t h e recei\.er 11:ic.k into t h e distilling flask is precluded. In Fig. 11. upper p a r t . are t h e receii-ers iflnt 1)CJrtnm
T H E J O C R , V d L O F I ; V D C ‘ S T R I A L A S D ENGIXEERIAVG C H E M I S T R Y
788
Erlenmeyer flasks of 2 j o a n d 300’ cc. c a p a c i t y ) . connected u p w i t h t h e condensers. T h e s t o p p e r of each receil-er carries t w o b e a d t u b e s , in addition t o t h e glass t u b e t h a t connects, b y means of r u b b e r t u b e , with t h e condenser. T h i s glass t u b e a n d t h e rubber t u b e could be dispensed with-the r u b b e r s t o p p e r in t h a t case being slipped over t h e e n d of t h e condenser. T h e condenser, or i t s glass extension. does not touch t h e
FIG.
11-FRONT
V I E W OF KJELD.4IiL
DISTILIJNG APPAR.4TUS
liquid in t h e receiver. T o begin t h e distillation. int r o d u c e t h e s t a n d a r d acid a n d indicator i n t o t h e receiver. b u t no water. Connect u p with t h e condendenser, t h e n fill t h e interstices of t h e beads with distilled w a t e r . I n lower p a r t of Fig. I 1 a r e s h o w n : ( a ) A never-gets-out-of-order carrier, or s u p p o r t , for Kjeldahl flasks. ( b ) A device (see t h e flask a t t h e extreme r i g h t ) which. by mere pressure o n a pinchcock, drops i n t o t h e flask (simultaneously washing its neck) t h e requisite q u a n t i t y of w a t e r ( a b o u t I O O t o 1 2 5 cc.) t o dilute t h e digestate. (c) X distillation flask, m a r k e d I O , connected u p with condensing t u b z a n d receiver. T h e condensing t u b e rises f r o m t h e connecting b u l b , passes t h r o u g h a slot (see Fig. I ) , over t h e edge of t h e water t a n k . i n t o t h e w a t e r ; along under t h e water a n d rises over t h e front edge of t h e t a n k on which i t r e s t s ; t h e only other point of s u p p o r t t o t h e condensing t u b e is t h e stopper in t h e distilling flask. I n case one desires t o bring t h e recei\.er on t h e same side with t h e distilling flaskst h e condensing t u b e . a f t e r dipping t h r e e or four inches i n t o t h e w a t e r , b e n d s b a c k t h r o u g h a slot over t h e same side of t h e t a n k (see t h e fifth flask f r o m t h e right in Fig. I , t h u s connected u p with its receiver).
X7o1.
j ,
NO.9
those of t h e b u l b , of t h e t u b e below t h e b u l b a n d of t h e t u b e a b o v e t h e b u l b t o t h e first b e n d , c a n . w i t h o u t d e t r i m e n t , be diminished b y a b o u t half, provided t h a t , in order t o use interchangeably flasks of differe n t lengths, t h e r e m u s t be sufficient length of t u b e between t h e first a n d second b e n d s t o p r e v e n t lifting t o o much of t h e t u b e out of t h e w a t e r in using flasks viith e x t r a long necks. With p l e n t y of cooling w a t e r . a 1 inch inside diameter a n d 8 or I O block-tin t u b e inches ( 2 0 t o 2 j c m . ) u n d e r w a t e r affords ample condensing surface. T h e cooling t a n k has t h e following measurements: length (for twelve condensers), I j3 c m . ; d e p t h , 2 0 c m . ; w i d t h a t t o p 2 6 . j cm., a t b o t t o m 2 1 c m . I n case receivers a n d distilling flasks a r e o n t h e s a m e side. t h e t a n k need b e only 4 or j c m . wide. B u t after t h e .distillation is over, these condensers c a n n o t be easily s t e a m e d o u t ? If t h e s t e a m i n g o u t is i n t e n d e d t o clean out t r a c e s of a m m o n i a , it is entirely superfluous in t h e case of these condenserst h e r e is no a m m o n i a t o clean o u t ; if it is i n t e n d e d t o clean o u t a n y fixed alkali. t h a t is something s t e a m c a n n o t d o ; t h a t is a function of w a t e r ; a n d these condensers can easily be carried t o a t a p . water r u n in a t t h e receiver e n d a n d o u t t h r o u g h t h e b u l b e n d . However, if one insists o n s t e a m i n g o u t . each of these condensers can easily a n d cheaply be furnished with it.s individual t a n k , each little t a n k with a s t o p p e r e d
’
DIlIESSIOXS OF THE COKDEXSISG TUBE A S D COSSECT-
BvLB-The b u l b (copper or block-tin), greatest diameter 6 or j c m . . height 8 t o I O c m . ; soldered t o t h e lower e n d of b u l b so as t o give good drainage b a c k i n t o t h e flask, is a t u b e (preferably block-tin) a b o u t 6 m m . ( l / 4 inch) inside d i a m e t e r , l e n g t h 7 t o 8 c m . : projecting 2 t o 3 cm. i n t o t h e t o p of t h e b u l b , is t h e condensing t u b e (block-tin) , diameter inside a b o u t 6 m m . length f r o m b u l b t o t o p of first bend, I O t o 1 2 c m . t o p of first b e n d t o middle of second bend a b o u t 2 0 cm., thence t o middle of t h i r d b e n d a b o u t 14 c m . . t h e n c e t o middle of f o u r t h b e n d a b o u t 18 c m . , t h e n c e t o end a b o u t 6 t o 7 c m . ; all of these measurements,except ISG
FIG
III--MODIFIED A P P 4 R A T U h
hole in t h e b o t t o m , t h r o u g h which t h e water can be drained i n t o a t r o u g h r u n n i n g u n d e r n e a t h a n d s u p porting all of t h e individual t a n k s . T h e writer h a s used experimentally a n d successfully for several years a similar little t a n k a n d condenser, interchangeably with t h e other condensers of t h i s a p p a r a t u s . In Fig. I is s h o w n at 6 a n d 7 a n e n d a n d a side view of t w o of a set of twelve copper Kjeldahl stills. T h e p a r t s a r e : a cylinder 13 c m . long a n d I O cm. i n diame t e r ; o n one e n d a t u b u l u s ; a t t h e other e n d , a n d pro-
Sept
191j
T H E J O 1 7 R S A L O F I S D C 7 S T R I S L -4 S D E S GI -1-E E RI S G C H E M I S T R E'
j e c t i n g i n t o it, 2 o r 3 e m . . a t u b e a b o u t 2 . 9 c m . i n d i a m e t e r (inside) a n d 2 j c m . l o n g ; p r o j e c t i n g i n t o t h e e n d of t h i s t u b e is t h e c o n n e c t i n g b u l b . and i n t o t h e conn e c t i n g lmlb t h e block-tin condensing t u b e . -111 p a r t s a r e soldered t o g e t h e r w i t h o r d i n a r y t i n solder, still and condensing t u b e f o r m i n g o n e c o n t i n u o u s piece. T h e c o n n e c t i n g b u l b , however! m a y b e dispensed w i t h , as it is of n o t m u c h use. T h e s e stills a r e as easily c h a r g e d . discharged a n d cleansed as a Iijeltlahl distilling flask; t h e s e o p e r a t i o n s a r e perf o r m e d . of course, t h r o u g h t h e t u b u l u s . T h e t u b u l u s m a y lie s t o p p e r e d ivith a c o r k ; b u t a r u b b e r s t o p p e r is pi-eferred---either inserted o r c l a m p e d o n . T h e c l a m p e d - o n s t o p p e r shom-n on still 6 w a s used t w o >-ears. a n d could d o u b t l e s s b e u s e d several y e a r s longer. One of t h e a d v a n t a g e s of t h e s e stills is t h a t t h e y practically e l i m i n a t e t h e t r o u b l e t h a t s t o p p e r s cause in t h e case of K j e l d a h l distilling flasks; t h e i r chief d r a w l i a c k is t h e t i m e ( a b o u t I j m i n u t e s t o a s e t of t e n ) c o n s u m e d in t r a n s f e r r i n g t h e digestage. O n l y t h e lower p a r t of t h e s e stills is c o r r o d e d ; n e w b o t t o m s a n d e n d s a r e t h e n soldered on. T h e writer designed a n d u s e d n still of t h i s k i n d six or eight y e a r s ago. Fil-e or s o years a g o h e p u t i n t o use a s e t of t w e l v e . T h e y were used with e n t i r e satisfaction for t w o y e a r s . u n d e r g o i n g repairs several t i m e s i n t h e meann*hile. T h e use of t h e m was discontinued. b e c a u s e t h e y were t h o u g h t t o lie n o longer economical i n view of tlie c h e a p n e s s a n d d u r a b i l i t y of J e n a glass, a n d i n T-iew of t h e t i m e w a s t e d i n transferring.
I
789
Fig. I11 s h o w s a n o t h e r m e t h o d of connecting t h e s e c o p p e r stills w i t h t h e condensing t u b e . n a m e l y , b y m e a n s of a n o r d i n a r y pipe coupling w i t h r u b b e r washer between. Despite t h e fact t h a t t h i s m e t h o d renders t h e t u b u l u s u n n e c e s s a r y , it was a b a n d o n e d in f a y o r of t h e t u b u l u s . A l t2 2 is shoivn a disc (copper o r blockt i n ) that is used in some of o u r connecting b u l b s . These discs a r e slightly less in d i a m e t e r t h a n t h e greatest inside d i a m e t e r of t h e b u l b s ; a r e laid in loose, n o t soldered; t h e y s h o u l d ha\-e n u m e r o u s n o t c h e s , a b o u t 0 . j m m . deep, a r o u n d tlie edge. T h e s t e a m impinges a g a i n s t t h i s disc. passes a r o u n d it a n d o u t i n t o t h e condensing t u h e . 1 I a n y t h o u s a n d s of nitrogen d e t e r m i n a t i o n s lia\-e b e e n m a d e m-ith t h i s a p p a r a t u s b y t h e n-riter a n d b y o t h e r s (in t h e case of t h e c o p p e r stills, b y t h e XI-riter o n l y ) . B u t y o u c a n n o t see w h a t is going on in t h e c o p p e r stills? X70u d o n o t need t o . B u t if t h e r e is f r o t h i n g ? T h e r e \\-ill b e no f r o t h i n g . except as t h e res u l t of b a d m a n a g e m e n t ; a n d b a d m a n a g e m e n t ought n o t t o occur oftener t h a n once o r twice p e r t h o u s a n d d e t e r m i n a t i o n s . Moreox-er, w h e n f r o t h i n g does occ u r . it will manifest itself a t t h e receil-er e n d of t h e c o n d e n s e r , a n d t h e d e t e r m i n a t i o n is lost. BUT t h e stills s o m e t i m e s get d r y a n d melt a p a r t ? T e s . thrr11ig11 gross carelessness. once i n p e r h a p s , a thousancl c a i i 4 . for t h e r e is. t o s t a r t n-ith! a b o u t z j o t o ~ ~ Occ'.O of lic!iiiil i n t h e still: t h e distillation is s t o p p e d w h e n aboi:?. io0 cc. of distillate h a s a c c u m u l a t e d i n t h e receix-er. ~ , A B O R h T O R Y OF
THE S o K T H C A R O L I S A D E P . 4 R T M E S T R1LEIGII.
N.
O F . \ < . R I C l I.T1 I,l:
c.
ADDRESSES CHEMICAL PATENTS-I
rcference to allied arts such as fertilizers, petroleum produrts, rubber manufacture, etc., all of which in\-olve chemical processes to a greater or less degree.
Bl- S E A B ~ I R C.Y MAS TICK^ Received M a y
11,1915
The subject of chemical patents and of patents for processes relating to industrial chemistry is one of the oldest, if not the oldest, in the realm of patents. As early as 1467 a patent was granted in Berne for the manufacture and sale of paper and in 1507 the Council of Ten in Venice granted an exclusive privilege for twenty years for the introduction of a secret process of mirror-making. During the first ten years at the beginning of the patent policy in England ( 1 j61-70) twelve of the eighteen patents granted were for 7-arious chemical products and processes. The chemical patents related to such subjects as soap, saltpeter, alum, sulfur, oil, salt, glass, and cloth- and leather-dressing. In the course of the next decade three of the ten patents granted related to chemistry, t'iz. : those for earthenware, glass and sulfur. The marked increase in the study and development of the arts relating to chemistry in the United States during the past decade and more has made i t imperative for all having t o do with the subject to gix-e careful attention to patents, to the ascertaining of what is patentable, how to properly protect inventive ideas and how to enforce the protection so given, as well as how t o avoid trespassing upon the rights of those holding patents with which the thing you are considering developing may conflict. The importance aut1 development of chemistry in the arts in the T'riited States is shown by the following comparative figures relating exclusively t o the manufacture of, chemicals without ' Special l e c t u r e r on Chemical P a t e n t s , D e p a r t m e n t of E n g i n e e r i n g , Columbia T-7niversity, 19 15
Chemical
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CIPITAL ISVESTED h I l N U F A C T U R E D PRODUCT
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