Chemical Indexing: The Research Chemist's Point of View -

chemist's point of view we shall be concerned with the relationship of indexing to the chemist's personal search in comparatively narrow fields. For t...
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CHEMICAL INDEXING: THE RESEARCH CHEMIST'S POINT OF VIEW* By LOUIS SCHMERLING Research and Development Laboratories Universal Oil Products Company, Des P l a i n e s , Illinois

INTRODUCTION In d i s c u s s i n g indexing f r o m the r e s e a r c h c h e m i s t ' s point of view we s h a l l be c o n c e r n e d with the relationship of indexing t o t h e c h e m i s t ' s personal s e a r c h i n comparatively n a r r o w fields. F o r t h e p u r p o s e s of t h i s p a p e r w e s h a l l a s s u m e that h e , like m o s t of u s i n i n d u s t r y at l e a s t , h a s available a g r o u p t r a i n e d t o m a k e a p r o f e s s i o n a l s e a r c h of the l i t e r a t u r e with r e g a r d t o b r o a d fields. Also, b e c a u s e I am an o r g a n i c c h e m i s t , I s h a l l h e r e e m p h a s i z e indexing f r o m t h e s t a n d point of o r g a n i c c h e m i s t r y ; I believe t h a t m o s t of m y c o m m e n t s , including e v e n the r e l a t i o n ship of n o m e n c l a t u r e t o indexing, will apply equally well t o o t h e r f i e l d s of c h e m i s t r y . The o r g a n i c c h e m i s t will u s u a l l y t u r n t o an index b e c a u s e he is looking f o r i n f o r m a t i o n on a compound, on a type of r e a c t i o n , o r on a c a t a l y s t f o r causing the compound t o u n d e r g o a c e r t a i n r e a c t i o n . He will u s u a l l y have i n mind q u e s tions s u c h a s : What a r e the physical and c h e m i cal p r o p e r t i e s of compound X ? Has compound X e v e r been t r e a t e d with compound Y o r c a t a l y s t A ? How d o e s one c o n v e r t compound X t o Compound Z ? How d o e s one c a r r y out a given c o n v e r s i o n (for e x a m p l e , alkylation, d e h y d r a tion, halogenation, oxidation, epoxidation, nit r a tion, sulfonation, g.) of a compound similar t o type A ? What is the m e c h a n i s m of t h e r e a c t i o n of X with Y ? Has the t h e r m o d y n a m i c s of the r e a c t i o n been s t u d i e d ? One m a y expect t o find a n s w e r s t o t h e s e q u e s t i o n s , if indeed they have been published, i n p e r i o d i c a l s (both s c i e n t i f i c and t r a d e j o u r n a l s ) , in t e c h n i c a l books, and i n the patent l i t e r a t u r e . While the index of a p a r t i c u l a r p e r i o d i c a l m a y i n itself be adequate and m a y b e t u r n e d t o i f t h e c h e m i s t h a s a n i d e a of the a p p r o x i m a t e p e r i o d of publication, it i s , of c o u r s e , u s u a l l y t o t h e a b s t r a c t j o u r n a l s t h a t he t u r n s f o r a n index t o the combined p e r i o d i c a l l i t e r a t u r e , and we s h a l l , t h e r e f o r e , begin o u r d i s c u s s i o n with t h e s e .

on t h e i n f o r m a t i o n a l r e a d y a t hand, t h e c h e m i s t m a y t u r n f i r s t t o t h e Author Index, t h e Subject Index, o r the F o r m u l a Index. If he believes that he h a s s e e n the d e s i r e d m a t e r i a l in a p a p e r by a p a r t i c u l a r author published i n a p a r t i c u l a r y e a r o r t h e r e a b o u t s , he probably will find t h e r e f e r e n c e m o s t quickly by turning to the author indexes f o r t h e y e a r s i n question. U s e of a n author index would seem t o b e fool-proof. After a l l , t h e r e is no p r o b l e m of choice of index w o r d o r n o m e n c l a t u r e i n volved. T h e s o l e p r o b l e m of both the c o m p i l e r and u s e r of t h e index is one of alphabetizing. N e v e r t h e l e s s , a m i n o r difficulty m a y s o m e t i m e s arise i f the s y s t e m is not fully understood. F o r e x a m p l e , I c a n r e c a l l being somewhat p e r t u r b e d on a n o c c a s i o n when I w a s looking f o r a c e r t a i n publication by P r o f e s s o r H e r b e r t C. Brown of P u r d u e University. The index n a m e "Brown, H e n r y , ' ' w a s followed by "Brown, H e r m a n , " i n s t e a d of by "Brown, H e r b e r t C." Since I knew that H e r b Brown had published m a n y p a p e r s during the y e a r , i t w a s obvious that I w a s looking f o r his n a m e in t h e w r o n g place. A glance down the column showed t h e n a m e "Brown, H. C.," and t h e d e s i r e d r e f e r e n c e . A few m o m e n t s c o n s i d e r a t i o n showed t h a t the i n d e x e r had u s e d a logical s y s t e m which I had not p r e v i o u s l y had o c c a s i o n to note. The H. Browns having only one given initial a r e l i s t e d f i r s t followed by those having two i n i t i a l s . Indexing i s alphabetical by i n i t i a l s r a t h e r than f i r s t n a m e s . Full f i r s t o r middle n a m e s a r e u s e d , i f known, only when n e c e s s a r y t o distinguish between a u t h o r s having the s a m e i n i t i a l s . When the full n a m e s a r e the s a m e , the a u t h o r ' s town is included i n p a r e n t h e s e s a f t e r his n a m e . This is probably as s e n s i b l e a s c h e m e a s any.for l i s t i n g n a m e s and is quickly u n d e r s t o o d once called t o t h e u s e r ' s attention. The s y s t e m is i l l u s t r a t e d i n t h e s e index n a m e s :

ABSTRACT JOURNALS

B r o w n , H. Brown, H a r o l d Brown, H a r r i s o n Brown, Henry ( C l i t h e r o e , Engl.) Brown, Henry ( D e t r o i t , Mich.) B r o w n , Henry (Madison, Wis .) Brown, H e r m a n Brown, H. A .

The A m e r i c a n c h e m i s t ' s m o s t i m p o r t a n t i n d e x e s a r e , of c o u r s e , t h e annual and collective (decennial) i n d e x e s of C h e m i c a l A b s t r a c t s , which is t r u l y the "Key t o t h e W o r l d ' s C h e m i c a l L i t e r a t u r e . " In s o m e c a s e s r e f e r e n c e a l s o m a y be m a d e to C h e m i s c h e s Z e n t r a l b l a t t , and t o B r i t i s h A b s t r a c t s , which, h o w e v e r , c e a s e d publication a s s u c h i n D e c e m b e r , 1953. C h e m i c a l A b s t r a c t s Author Index.--Depending on the type of i n f o r m a t i o n d e s i r e d as w e l l a s

'Presented before the Division of Chemical Literature, ACS Meeting, New Yolk, N . Y., September 11, 1957.

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Brown, Brown, Brown, Brown, Brown, Brown, Brown, Brown, Brown, Brown, Brown,

H. B. H. C. H. D. J. J a m e s Boyer J a m e s Brooking John B . J . C. J o h n F. J o s e p h F. J. G.

'CHEMICAL INDEXING: T H E RESEARCH CHEMIST'S POINT OF VIEW

The H. C . Brown l i s t i n g p r e s u m a b l y will b e changed t o H e r b e r t C . Brown i n the 1958 index b e c a u s e the n a m e H e n r y C. Brown a l s o will b e indexed. T h e C-iical A b s t r a c t s Author Index, t h e n , p r o v i d e s a r a p i d m e a n s of obtaining i n f o r m a t i o n when one is fa.miliar with t h e n a m e s of t h e w o r k e r s i n t h e f i e l d . It i s , we m a y add, p a r t i c u l a r l y useful d u r i n g the i n t e r i m which m u s t of n e c e s s i t y e x i s t b e f o r e the a p p e a r a n c e of t h e "Subject Index," as i s t.he s e m i - m o n t h l y author index. C h e m i c a l A b s t r a c t s F o r m u l a Index.--When s e e k i n g i n f o r m a t i o n about a p a r t i c u l a r c h e m i c a l compound, one m a y t u r n t o e i t h e r t h e F o r m u l a Index o r t h e S.ubject Index. T h e l a t t e r is p r e f e r a b l e f o r well-known compounds which have r e c e i v e d m u c h study; indeed, when one looks t h e s e up i n the F o r m u l a Index, he is told t o " s e e " t h e compound i n the Subject Index. On t h e o t h e r hand, t h e F o r m u l a Index is p r e f e r r e d by m a n y c h e m i s t s f o r the l e s s c o m m o n c h e m i c a l s s i n c e i t s u s e i s independent of a knowledge of the r u l e s of n o m e n c l a t u r e and indexing f o l lowed by t h e j'ournal. F u r t h e r m o r e , i s o m e r s a r e g r o u p e d t o g e t h e r i n t h e f o r m u l a index w h e r e a s they :may be widely s e p a r a t e d i n the s u b j e c t index i n which they a r e n a m e d s y s t e m a t i c a l l y . F o r e x a m p l e , i n t h e 1955 F o r m u l a Index t h r e e c h l o r o h e p t a n e s a r e l i s t e d u n d e r C7H15C1: "heptane, c h l o r o , " "hexane ,2 - c h l o r o 2 - m e t h y l , " and "pentane, chlorodimethyl." In the s u b j e c t index one would have t o look i n t h r e e p l a c e s : u n d e r "heptane," "hexane," and "pent a n e . " T h e r e i s , n e v e r t h e l e s s , a n advantage i n looking in t h e Subject Index. The F o r m u l a Index m e r e l y l i s t s t h e p a g e s on which the p a r t i c u l a r compound ( f o r e x a m p l e , chlorodimethylpentane) is d e s c r i b e d . T h e Subject Index, on the o t h e r hand, m a k e s m e n t i o n of the type of i n f o r m a t i o n given i n e a c h litem l i s t e d ; f o r e x a m p l e , "2(and 3) - C h l o r o - 2 , 3 - d i m e t h y l p e n t a n e , f o r m a t i o n f r o m t X t - B u C 1 r e a c t i o n with p r o p e n e ' ' and " 3 - C h l o r o Z,Z-dimethylpentane, a t t e m p t e d s y n t h e s i s of." Such a l i s t i n g u s u a l l y will be sufficient t o p e r m i t the u s e r t o conclude w h e t h e r i t is w o r t h while f o r h i m t o look up the a b s t r a c t . The F o r m u l a Index d o e s have a n i m p o r t a n t advantage i n t h a t i t l i s t s t h e C.A. index n a m e of the c h e m i c a l c o m p o u n d s , thus making i t u n n e c e s s a r y f o r t h e u s e r t o have e x p e r t knowledge of the & C nomenclature s y s t e m . C h e m i c a l A b s t r a c t s Subject Index.--As i s annually indicated i n the i n t r o d u c t i o n t o the Subject Index, r e a d i n g of the introduction i s not e s s e n t i a l f o r u.se of t h e index. Indeed, i t i s m y g u e s s t h a t only a v e r y s m a l l p r o p o r t i o n of the u s e r s have e v e r b o t h e r e d t o r e a d m o r e than a p a r a g r a p h o r t.wo of t h e introduction. P e r h a p s t h e s o l e r e f e r e n c e m a d e w a s to d e t e r m i n e t h e m e a n i n g of the a s t e r i s k o r d a g g e r following the n a m e s of s o m e compounds. Many undoubtedly have studied the d i s c u s s i o n of the n o m e n c l a t u r e of c h e m i c a l compounds which a p p e a r e d i n the

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Introduction t o t h e 1945 Subject Index, but r e l a t i v e l y few have r e a d t h e d i s c u s s i o n of t h e g e n e r a l p o l i c i e s of t h e index. It is a x i o m a t i c t h a t if t h e u s e r u n d e r s t a n d s t h e p r o b l e m s and m e t h o d s of t h e i n d e x e r h e will be able t o find t h e sought f o r i n f o r m a t i o n m o r e efficiently. T h e b e t t e r his understanding of t h e index, the m o r e l i k e l y will h e b e t o t u r n t o t h e r i g h t p l a c e at once when s e e k i n g - d a t a on a p a r t i c u l a r compound o r r e a c t i o n . I f - h e is s e a r c h i n g f o r i n f o r m a t i o n on a n u m b e r of a l k y l b e n z e n e s , h e will know that he will find t h e pentylbenzenes u n d e r "Benzene, pentyl" and the hexylbenzenes u n d e r "Hexane, phenyl." If he is i n t e r e s t e d i n t h e u n s a t u r a t e d compounds, he will know t h a t allylbenzene is found under " B e n z e n e , allyl" while t h e butenyl and pentenylb e n z e n e s a r e found u n d e r "Butene, phenyl" and " P e n t e n e , phenyl." On t h e o t h e r hand, e v e n i f he is u n a w a r e of the p r i n c i p l e s involved, t h e a m p l e u s e of c r o s s r e f e r e n c e s will i n f o r m him of the p r o p e r index headings. H e will t h e n with m o r e o r l e s s d i s g u s t t u r n t o t h e p r o p e r place. t h e amount of d i s g u s t depending on t h e p a r t i c u l a r c a t e g o r y i n t o whicn h e falls. T h e first, and I hope t h e l a r g e r , g r o u p are t h e patient c h e m i s t s who, when t h e y have g u e s s e d wrong, will c a l m l y t u r n t o t h e indicated location, blaming only t h e m s e l v e s f o r not having a better knowledge of t h e index. M e m b e r s of t h e second g r o u p , of whom I know a few, will l o s e t h e i r t e m p e r s , will c a l l down t h e w r a t h of heaven on t h e i n d e x e r , and will have a n u r g e t o t o s s t h e index out t h e window. The s e c o n d c a t e g o r y a l s o includes c h e m i s t s , who, without any understanding of o r s y m p a t h y f o r t h e p r o b l e m s of t h e i n d e x e r , feel t h a t the index should be a r r a n g e d i n a c c o r d a n c e with t h e i r pet p e r s o n a l f a v o r i t e s u b j e c t s . They m a y , f o r e x a m p l e , f e e l t h a t all glycols should b e indexed u n d e r G. They a r e annoyed by t h e f a c t t h a t g e n e r a l r e f e r e n c e s t o t h e compounds a r e l i s t e d u n d e r glycols while t h e individual g l y c o l s , except t h o s e having c o m m o n n a m e s (e.p., ethylene glycol) a r e indexed as alkanediols (e.g., propanediol and butanediol). D e r i v a t i v e s i n h i c h substitution is on t h e c a r b o n a t o m a r e l i s t e d u n d e r the individual glycol o r diol while t h o s e i n which substitution is o n t h e oxygen a r e l i s t e d u n d e r t h e h y d r o c a r b o n as alkoxy d e r i v a t i v e s . T h e s e u s e r s d o not a p p r e c i a t e the value of s y s t e m a t i c indexing o r of having the individual compounds a s m a j o r h e a d i c g s r a t h e r t h a n a s subheadings u n d e r glycol. It is pointed out i n t h e Introduction t o the C.A. Subject Index t h a t m a n y f a c t o r s need t o b e t a k e n into c o n s i d e r a t i o n i n deciding on s u b j e c t e n t r i e s t o be m a d e f o r a n a b s t r a c t . T h e s e include t h e " a u t h o r ' s p u r p o s e , his point of v i e w , t h e new d a t a r e p o r t e d , new o r modified m e t h o d s and a p p a r a t u s u s e d i n obtaining t h e s e d a t a , significant r e l a t i o n s brought out, t h e o r i e s f o r m u l a t e d , new s u b s t a n c e s p r e p a r e d , s u g g e s t e d

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Louis Schmerling

o r likely u s e s f o r new s u b s t a n c e s (as i n indexing p a t e n t s ) , p o s s i b i l i t i e s f o r utilization of material (as c e r t a i n s o - c a l l e d w a s t e m a t e r i a l ) , d e s i r a b l e groupings b a s e d on p r o p e r t i e s , p r o c e s s e s o r o p e r a t i o n s , and effects s u c h as i n d u s t r i a l poisoning." B e c a u s e the u s e r l s point of view m a y not always b e the s a m e as t h a t of the author and hence of the i n d e x e r , the e n t r y will not always be a t the point f i r s t t u r n e d t o by t h e u s e r . L e t u s look a t s o m e e x a m p l e s i n t h e 1954 Subject h d e x . A s s u m e t h a t we a r e i n t e r e s t e d i n the r e action of benzene with 1- b r o m o - 3 - c h l o r o p r o p a n e i n the p r e s e n c e of a l u m i n u m c h l o r i d e . W e will find r e f e r e n c e s u n d e r "Benzene, r e a c t i o n with 1 - b r o m o - 3 -chloropropane , ' I u n d e r " P r o p a n e , 1 - b r o m o - 3 - c h l o r o , r e a c t i o n with benzene," and under "Aluminum c h l o r i d e , i n r e a c t i o n of b e n z e n e with 1-bromo-3-chloropropane." If we a r e i n t e r e s t e d i n the r e a c t i o n of benzene with 1,3butanediol, we will find a r e f e r e n c e , "Benzene, r e a c t i o n with 1,3-butanediol1'; h o w e v e r , if we look u n d e r 1,3-butanediol, we will not find the analogous r e f e r e n c e t o r e a c t i o n with benzene. Instead, the a b s t r a c t i s indexed u n d e r "1,3Butanediol, hydroxyalkylation with." Obviously, the a u t h o r ' s point of view w a s that of t h e u s e of the glycol to i n t r o d u c e the hydroxybutyl g r o u p and the p a p e r i s s o indexed. The subheading o r modifying p h r a s e should be s u c h as t o l e t the u s e r know whether it i s w o r t h his while t o refer t o the a b s t r a c t . S i m i l a r l y , l e t u s s e a r c h the 1955 Subject Index f o r p a p e r s dealing with t h e alkylation of benzene with propene t o obtain cumene. Under the heading, "Benzene," we find "Benzene, isopropylation with p r o p e n e , i n c r e a s i n g yield of butylbenzene homolog - f r e e i s o p r o p y l h y d r o c a r b o n s in." About t h r e e columns l a t e r , we find "Benzene, r e a c t i o n s of, with propene." Under "Propene" we find " P r o p e n e , benzene alkylation c a t a l y s t in," and with, B F ~ * H ~ P O ~ - - B F ~ "as ZO " P r o p e n e , benzene alkylation with, i n c r e a s i n g yield of butylbenzene h o m o l o g - f r e e i s o p r o p y l h y d r o c a r b o n s in," and " P r o p e n e , benzene alkylation with, t h e r m o d y n a m i c s of." About one and one-half columns l a t e r we find, " P r o p e n e , reactions of, with benzene" and " P r o p e n e , r e a c t i o n s of, with benzene i n the p r e s e n c e of Al and 2bromopropane." R e f e r e n c e t o t h e a b s t r a c t s i m m e d i a t e l y shows t h a t f r o m the point of view of the i n d e x e r and of s o m e u s e r s , a t l e a s t , t h e s e headings a r e the p r o p e r o n e s . N e v e r t h e l e s s , i f one is i n t e r e s t e d i n e v e r y r e f e r e n c e t o the i n t e r action of benzene with p r o p e n e r e g a r d l e s s of the p a r t i c u l a r e m p h a s i s , he would p r e f e r t o have a l l of t h e m u n d e r one modifying p h r a s e . Howe v e r , m u c h as he would l i k e t o s e e t h e i t e m s of i n t e r e s t t o h i m indexed t o g e t h e r , i t is r a t h e r obvious t h a t this is a Utopian, and usually s e l f i s h , g o a l . A s a r e s u l t , the u s e r m u s t k e e p in mind the p o s s i b i l i t y of finding his i n f o r m a t i o n i n m o r e than one location.

I m u s t a d m i t t h a t f r o m m y own s e l f i s h viewpoint I probably would u s u a l l y find o p t i m u m u s e of i f all the a b s t r a c t s dealing with r e a c t i o n s w e r e indexed m e r e l y i n t h e f o r m "Compound A, r e a c t i o n with compound B i n t h e p r e s e n c e of C a t a l y s t C" r a t h e r than h a v ation ing t h e occasional "Compound A, alkylation o r halogenation, o r oxidaof (e.g., tion But I am r e a l l y not bothered m u c h b y t h e f a c t t h a t the r e f e r e n c e s I s e e k a r e not bunched together. I believe t h a t one of t h e i m p o r t a n t bonuses i n using t h e index (and a b s t r a c t v o l u m e s ) is t h a t I often s e e additional index headings (and a b s t r a c t s ) which, while a t the m o m e n t a r e not d i r e c t l y r e l a t e d t o t h e subject a t hand, s e r v e t o s t i m u l a t e new i d e a s . T h e s e extra dividends m o r e than m a k e up f o r the t i m e spent i n checking all p o s s i b l e v a r i a t i o n s of the index w o r d s . It is a l s o a good r e a s o n why t h e r e s e a r c h c h e m i s t should, as often as f e a s i b l e , do s o m e of h i s own s e a r c h i n g r a t h e r than having i t a l l done f o r h i m . It is worthwhile t o c o n s i d e r whether G. might expand its s e r v i c e s by including ( h e n c e , indexing) material not a t p r e s e n t a b s t r a c t e d . T i t l e s of a c a d e m i c t h e s e s , f o r e x a m p l e , have been r e c o r d e d , but only when available on m i c r o f i l m and l i s t e d i n D i s s e r t a t i o n A b s t r a c t s . It would b e useful t o r e c o r d a l s o t i t l e s of t h e s e s l i s t e d i n t h e A m e r i c a n C h e m i c a l Society D i r e c t o r y of G r a d u a t e R e s e a r c h . Whether the r e sulting - information i s w o r t h the added c o s t i n view of t h e eventual publication of m o s t t h e s e s , Editors t o determine. I leave to the Similarly, a b s t r a c t s a review paper s u c h as those a p p e a r i n g i n C h e m i c a l Reviews by stating that i t is a r e v i e w with x n u m b e r of r e f e r e n c e s . Analogous r e v i e w s a p p e a r i n g a s c h a p t e r s i n a technical book a l s o have been l i s t e d occasionally. Such l i s t i n g is c e r t a i n l y t o b e r e c o m m e n d e d s i n c e t h i s will r e s u l t i n being a m o r e complete index of the c h e m ical literature. C h e m i s c h e s Z e n t r a l b l a t t . -- While I r e a l i z e t h a t " c o m p a r i s o n s a r e odious," I f e e l that i t is w o r t h while, indeed n e c e s s a r y , f o r o u r p r e s e n t p u r p o s e s t o c o m p a r e C h e m i c a l A b s t r a c t s with C h e m i s c h e s Z e n t r a l b l a t t . Both Author Indexes u s e the s a m e s y s t e m , e v e n with r e g a r d t o a l phabetizing a u t h o r ' s n a m e s . The F o r m u l a Indexes, however, a r e quite different. C h e m i cal A b s t r a c t s u s e s the Hill s y s t e m ; C h e m i s c h e s Z e n t r a l b l a t t , t h e R i c h t e r s y s t e m . E a c h gives a unique a r r a n g e m e n t of e m p i r i c a l m o l e c u l a r f o r m u l a s and n e i t h e r h a s any m a r k e d advantage o v e r t h e o t h e r . On the o t h e r hand, t h e type of i n f o r m a t i o n given i n t h e two indexes d o e s diff e r . The C h e m i c a l A b s t r a c t s F o r m u l a Index is f a i r l y independent of the Subject Index and, as a l r e a d y mentioned, m e r e l y l i s t s the v a r i o u s i s o m e r s by n a m e and gives page r e f e r e n c e s without modifying p h r a s e s f o r all but the v e r y c o m m o n compounds. On the o t h e r hand, the

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F o r m u l a and Subject Indexes of C h e m i s c h e s Z e n t r a l b l a t t a r e not independent. Detailed s u b headings a r e given i n e i t h e r t h e Subject Index o r t h e F o r m u l a Index and t h e r e s e e m s to be no way of knowing i n advance i n which a f a i r l y common compound will a p p e a r . F o r e x a m p l e , . i n t h e 1954 F o r m u l a Index we find u n d e r C7H16 the i n s f r u c t i o n s to s e e heptane and isoheptane i n t h e Subject Index; six o t h e r heptanes a r e t h e n l i s t e d , c o m p l e t e with subheadings and page n u m b e r s . S i m i l a r l y , t o l u e n e , xylene and cumene ( i s o p r o pylbenzene) a r e indexed i n the Subject Index; ethylbenzene, 2'-propylbenzene, and ethyltolu e n e s , in the F o r m u l a Index. It probably i s - a s a f e b e t t h a t e v e n t h e m o s t f r e q u e n t u s e r of t h e Z e n t r a l b l a t t camnot g u e s s f r o m t i m e t o t i m e w h e r e he will find the d e t a i l e d r e f e r e n c e s f o r t h e p a r t i c u l a r compound of i n t e r e s t . T h e r e s e e m s to be 1it:tle s y s t e m o r c o n s i s t e n c y . F u r t h e r m o r e , whi1.e t h e F o r m u l a Index d o e s have c r o s s r e f e r e n c : e s to the Subject Index, t h e l a t t e r contains only a. r e l a t i v e l y s m a l l n u m b e r of c r o s s r e f e r e n c : e s . F o r e x a m p l e , "Methylamin s . CH5N" and "Methylbromid s . CH3Br," but no mention a t a l l of s u c h compounds a s e t h y l benzene and m e t h y l s t y r e n e . The only hint a t t h e s y s t e m u s e d is a single s e n t e n c e appea.ring on the first page of the i n d e x which s t a t e s , "Those compounds, f o r which r e f e r e n c e t o a location i n t h e Subject Index is not m a d e i n ita.lics, a r e found only i n the F o r m u l a Index." The c h e m i s t knows t h a t i f he finds a d e t a i l e d l i s t i n g of t h e compound i n t h e F o r m u l a Index, he will find none in the Subject Index. On the o t h e r hand, i f he finds no mention a t a l l of the compound i n the Subject Index, he m u s t s t i l l r e f e r to the F o r m u l a Index i n o r d e r to d e t e r m i n e whether o r not the compound i s l i s t e d . Unlike the C h e m i c a l A b s t r a c t s Index, the C h e m i s c h e s Z e n t r a l b l a t t F o r m u l a Index l i s t s only d e r i v a t i v e s of c a r b o n . Inorganic compounds a r e not included. The R i c h t e r s y s t e m w a s , of c o u r s e , not intended f o r i n o r g a n i c compounds a n d , u n l e s s modified, cannot be applied t o t h e m . The Hill s y s t e m , on the o t h e r hand, a p p l i e s equally well to both o r g a n i c and i n o r g a n i c compounds. A compound's n a m e in the Z e n t r a l b l a t t F o r m u l a Index u s u a l l y i s followed by i t s m e l t ing point o r boiling point. This f e a t u r e obviously i s a c a r r y o v e r f r o m R i c h t e r ' s "Lexikon." Whether o r not: s u c h p h y s i c a l d a t a a r e i m p o r t a n t i n an index i s debatable. It d o e s , of c o u r s e , give the index volume additional u s e a s a r e f e r e n c e v o l u m e , but one which cannot b e r e l i e d on definitely si.nce t h e r e i s no a s s u r a n c e t h a t a p a r t i c u l a r compound will be l i s t e d . C h e m i c a l A b s t r a c t s g i v e s melting o r boiling points only in the c a s e of unnamed (unidentified) o r g a n i c compounds. In many c a s e s Z e n t r a l b l a t t l i s t s m o r e than one n a m e f o r the s a m e compound. T h u s , t h e r e i s t h e e n t r y "C2H50C1 Athylenchlorhydrin

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(Chlor hydr i n , G1ykolchlor h y d r i n , 2 Chlor a t ha nol, -Chlorathylalkohol)." C h e m i c a l Abs t r a c t s , on the o t h e r hand, g i v e s only one n a m e , t h e index n a m e , s i n c e one of the p r i m a r y p u r p o s e s of the F o r m u l a Index is aid in the l o c a tion of compounds i n t h e Subject Index. The l i s t s the compound j u s t F o r m u l a Index of mentioned a s "C2HgC10 ( s e e a l s o Ethanol, chloro-) .I' As indicated above, the C h e m i c a l A b s t r a c t s Subject Index has the disadvantage f o r s o m e u s e r s that it in m a n y c a s e s f a i l s t o g r o u p s i m i l a r things i n one location. Such grouping is i n h e r e n t i n the Z e n t r a l b l a t t F o r m u l a Index (except f o r t h o s e compounds w h e r e the u s e r i s r e f e r r e d t o t h e Subject Index). F o r e x a m p l e , u n d e r CqHgC1 we find five n a m e s indexed: butyl c h l o r i d e , =-butyl c h l o r i d e , =-butyl c h l o r i d e , isobutyl c h l o r i d e , and t s - b u t y l c h l o r i d e . The subheadings a r e a r r a n g e d in o r d e r s i m i l a r t o that u s e d by B e i l s t e i n : p r e p a r a t i o n , p h y s i c a l p r o p e r t i e s , and r e a c t i o n s with v a r i o u s s u b s t a n c e s . The C h e m i c a l A b s t r a c t s e n t r y r e a d s "CqHgCl See Butane, c h l o r o - ; P r o p a n e , chloromethyl-." The f o u r i s o m e r i c butyl c h l o r i d e s a r e thus divided into two g r o u p s , one indexed at "Butane" and the o t h e r a t "Propane." The modifying p h r a s e s a r e again in alphabetical r a t h e r than "Beilstein" order. The Subject Index of C h e m i s c h e s Z e n t r a l G,like the F o r m u l a Index, groups o r c l a s s i f i e s the r e f e r e n c e s . T h u s , using again the e x a m p l e of the r e a c t i o n of benzene with propene we find i n the 1954 Subject Index under t h e heading "Benzol" a group of e n t r i e s concerning t h e r e a c t i o n with olefins a s s u c h , with olefins i n the p r e s e n c e of m e t a l l i c aluminum and halogen d e r i v a t i v e s , with propylene in the p r e s e n c e of B 4 0 7 ( H 3 P 2 0 6 ) 2 , of c a t a l y s t s of the system H Z O ' B F ~ * H ~ P O ~ ' B and F ~of, s u l f u r i c a c i d , and r e a c t i o n s with propene p o l y m e r s . Under propylene we find r e f e r e n c e s t o four a b s t r a c t s on i t s r e a c t i o n with benzene and one t o the r e a c t i o n of propylene p o l y m e r with benzene. No modifying p h r a s e s a s to the type of c a t a l y s t i n the r e a c t i o n s with propylene a r e mentioned here. Those who p r e f e r to have t h e i r r e f e r e n c e s grouped t o g e t h e r probably p r e f e r the C h e m i s c h e s Z e n t r a l b l a t t s y s t e m . T h e r e i s , n e v e r t h e l e s s , an - index which I b e i m p o r t a n t f e a t u r e of the C.A. l i e v e outweighs the p o s s i b l e advantage of the Z e n t r a l b l a t t c l a s s i f i c a t i o n s y s t e m , n a m e l y , the f a c t that C A . u s e s a single l i n e f o r each e n t r y w h e r e a s Z e n t r a l b l a t t u s e s runnineu DarapraDhs, C h e m i c a l A b s t r a c t s i s much m o r e r e a d i l y scanned than i s t h e G e r m a n index and one probably can go through a long column of m o d i fying p h r a s e s m o r e quickly than he can r e a d through the s o l i d block of fine p r i n t i n the p a r t i c u l a r p a r a g r a p h of the Z e n t r a l b l a t t to find the d e s i r e d r e f e r e n c e s .

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Louis S c h m e r l i n g

F u r t h e r m o r e , a c l a s s i f i c a t i o n index m a y overlook t o p i c s t h a t a r e r e l a t e d i n the mind of t h e u s e r but not t h a t of the i n d e x e r . F o r e x a m p l e , in t h e Z e n t r a l b l a t t Subject Index s u b headings on cycloalkylation and halomethylation are grouped under alkylation as a r e a c a d e m i c p a p e r s o n the alkylation of h y d r o c a r b o n s ; on the o t h e r hand, t h e u s e r is told t o r e f e r t o the s e c t i o n o n hydrocarbons f o r a b s t r a c t s on technical alkylation and dealkylation of h y d r o c a r b o n s . F o r 0 - a l k y l a t i o n of alcohols and phenols he i s told t o see e t h e r s ; f o r S-alkylation of m e r c a p tans, he is r e f e r r e d t o s u l f i d e s . Cyanoalkylation is indexed under addition r e a c t i o n s . Other alkylations a r e included with F r i e d e l - C r a f t s r e a c t i o n s . The Chemical A b s t r a c t s index heading "Alkylation" includes t h e s t a t e m e n t "(See a l s o Aralkylation, Chloroalkylation, Cycloalkylation. Isopropylation, Methylation) . I ' Neither index m e n t i o n s , f o r e x a m p l e , hydroxyalkylation. Obviously, t h e u s e r m u s t think of a l l p o s s i b l e index w o r d s and u s e the index accordingly. He should not expect t o have h i s s e a r c h m a d e f o r him by t h e c o m p i l e r of the index; he should m e r e l y hope t h a t he h a s a reasonably good understanding of t h e index s y s t e m and should not b e annoyed o r l o s e patience i f he has to look in m o r e than one o r two p l a c e s f o r the i n f o r m a tion d e s i r e d . C h e m i s c h e s Z e n t r a l b l a t t would be e a s i e r t o u s e if it adopted t h e C L . s c h e m e of adding a l e t t e r t o the page number t o indicate the p a r t of the page on which t h e information sought i s printed. P a t e n t Indexes.-The c h e m i c a l information of p a t e n t s is, of c o u r s e , indexed like any o t h e r c h e m i c a l s u b j e c t m a t t e r . The inclusion of the letter "Pr'with the page number in Chemical A b s t r a c t s and of the a s t e r i s k i n C h e m i s c h e s Z e n t r a l b l a t t i n f o r m s t h e u s e r t h a t the a b s t r a c t is t h a t of a patent. The n u m e r i c a l index of patents obviously is of no u s e when t h e u s e r does not know the patent number. C o n v e r s e l y , it helps him t o g e t a quick i d e a of the patent content when he has the n u m b e r of the patent. It is fortunate t h a t the a b s t r a c t j o u r n a l s a b s t r a c t patents. The United S t a t e s P a t e n t Gazette h a s weekly and annual i n d e x e s , but t h e s e a r e only author (inventor) indexes and a r e of little help i n s e a r c h i n g f o r patents on a p a r t i c u l a r subject. Before the middle of 1954, the annual i n d e x e s , a s well a s the weekly i n d e x e s , l i s t e d the patentees and t h e t i t l e of the patent. Beginning i n the m i d y e a r of 1954 and continuing through 1955 the index contained only the n a m e s of the inventor and his a s s i g n e e and the patent n u m b e r . T h i s saved a lot of s p a c e ; the 1955 Index of P a t e n t s I s s u e d f r o m the United S t a t e s P a t e n t Office h a s only 449 pages devoted to the list of p a t e n t e e s . However, t h i s m a n n e r of i n dexing apparently m e t with objections; beginning in 1956 t h e patent t i t l e a s well a s the n a m e s of

the inventor and a s s i g n e e is given. The l i s t of patentees and t i t l e s i n the 1956 Index occupies 886 pages. Of c o u r s e , the patent l i t e r a t u r e c h e m i s t will have available the U.S. P a t e n t Office Manual of C l a s s i f i c a t i o n , a l i s t of c l a s s e s and s u b c l a s s e s by g e n e r a l t o p i c s , narrowing t o the m o r e specific. He will p r o c e e d d i r e c t l y t o the patents of the d e s i r e d s u b - c l a s s . C u r r e n t Chemical P a p e r s --Be c au s e B r i t i s h A b s t r a c t s c e a s e d publication i n D e c e m b e r , 1953, I s h a l l s a y nothing m o r e about it h e r e . It i s p e r t i n e n t to d i s c u s s briefly one of i t s offspring, . - C This i s not an a b s t r a c t j o u r n a l but does have s o m e analogous u s e s . It i s ' a n index o r , m o r e str.ictly speaking, a table of contents of c u r r e n t l i t e r a t u r e , the c u r r e n t signifying l i t e r a t u r e only one month old. By publishing the t i t l e s of p a p e r s C u r r e n t Chemical P a p e r s c a l l s a t t e n tion to new work m o r e quickly than an a b s t r a c t j o u r n a l can. The e d i t o r s s t a t e that it i s i n tended a s a guide to c h e m i s t s ' reading and that t h e r e f o r e no index i s published. The m a j o r advantage of the publication d i s a p p e a r s , of c o u r s e , a s soon a s the v a r i o u s a b s t r a c t i n dexes a p p e a r . The j o u r n a l divides p a p e r s into t h i r t e e n c l a s s e s including the c h e m i c a l a s p e c t s of s u b a t o m i c s , phase s t r u c t u r e and p h a s e r e l a t i o n , colloid and m a c r o m o l e c u l e s , r e a c t i o n kinetics and r e a c t i o n m e c h a n i s m , t h e r m o d y n a m i c s , i n o r g a n i c , o r g a n i c , a n a l y s i s , and a p p a r a t u s and techniques. The o r g a n i c s e c t i o n i s subdivided into: aliphatic, a m i n o - a c i d s and p r o t e i n s , c a r b o h y d r a t e s , homocyclic, t e r p e n e s and s t e r o i d s , h e t e r o c y c l i c , o r g a n o m e t a l l i c and o r g a n o m e t a l l o i d , and m i s c e l l a n e o u s , The page layout i s such that i t i s s u r p r i s i n g l y e a s y t o s c a n the t i t l e s and pick out the p a p e r s of i n t e r e s t . I know s o m e r e s e a r c h c h e m i s t s who p r e f e r to spend t h e i r t i m e glancing through C u r r e n t Chemical P a p e r s r a t h e r than through Chemical A b s t r a c t s because of the p r o m p t n e s s with which the p a p e r s a p p e a r i n the B r i t i s h journal and b e c a u s e of the speed with which it can be "read." Actually, of c o u r s e , the two supplem e n t each o t h e r .

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TECHNICAL BOOKS It s e e m s u n n e c e s s a r y to point out that technical books, p a r t i c u l a r l y those of m o r e than a few hundred p a g e s , should have good indexes if they a r e to be u s e d efficiently. Depending upon the type of book, the headings in the subject index can be l a r g e l y the names of compounds o r of r e a c t i o n types o r t h e o r i e s . L i b e r a l u s e of subheadings i s highly d e s i r a b l e . Author indexes a r e a l s o quite useful p a r t i c u l a r l y when the u s e r ' s i n t e r e s t l i e s in obtaining a s u r v e y of a p a r t i c u l a r a u t h o r ' s viewpoints.

CHEMICAL INDEXING:

THE RESEARCH CHEMIST'S POINT O F VIEW

Subject indexes which have no subheadings w h a t s o e v e r a r e u s u a l l y of r e l a t i v e l y l i t t l e value. Even the m o s t patient c h e m i s t will b e m o r e than a l i t t l e p e r t u r b e d t o find t h e heading b e n z e n e , f o r e x a m p l e , followed by twenty o r t h i r t y o r even one hundred page n u m b e r s t o e a c h of which he m u s t t u r n i n o r d e r t o find t h e one containing t h e r e a c t i o n of benzene with p r o p e n e . Fortunately, such indexes a r e in the minority, but they a r e fa.r f r o m r a r e . S o m e t i m e s a t a b l e of contents will show sufficient c l a s s i f i c a t i o n a s t o m a k e it u n n e c e s s a r y t o r e f e r to t h e index. T h e u s e r will p r e f e r t o leaf through the p o r t i o n of t h e c h a p t e r i n q u e s t i o n to pic:k up not only t h e d i r e c t l y d e s i r e d i n f o r m a t i o n but a l s o r e l a t e d points t h a t he might not o t h e r w i s e c o n s i d e r .

LABORATORY NOTEBOOKS The i n t e r n a l l i t e r a t u r e of a company s u c h as the t e c h n i c a l r e p o r t s m u s t a l s o b e indexed if full value is t o b e d e r i v e d f r o m t h e m . Since t h e s e t e c h n i c a l r e p o r t s a r e i n t h e p r o v i n c e of the l i t e r a t u r e c h e m i s t I s h a l l s a y no m o r e about t h e m . However, I s h a l l d e s c r i b e b r i e f l y m y p e r s o n a l e x p e r i e n c e both a s a n i n d e x e r and i n dex u s e r with r e g a r d t o a n o t h e r type of i n t e r n a l l i t e r a t u r e , n a m e l y , l a b o r a t o r y notebooks. B e c a u s e I. have b e e n c o n c e r n e d with e x p l o r a t o r y r e s e a r c h , t h e i n v e s t i g a t i o n s I have c a r r i e d out halve been quite v a r i e d and it would often be quite difficult t o l o c a t e a p a r t i c u l a r e x p e r i m e n t without s o m e s o r t of index. The s y s t e m which I have adopted is v e r y s i m p l e . The first two p a g e s of t h e notebook a r e l e f t blank f o r t h e index. The i n d e x i t s e l f is b a s e d on t h e n a m e s of the r e a c t a n t s and t h e c a t a l y s t , if used. F o r e x a m p l e , if one of t h e s u b j e c t s u n d e r i n v e s t i g a t i o n is t h e r e a c t i o n of benzene with v a r i o u s u n s a t u r a t e d compounds t h e i n d e x l i n e will have t h e word "Benzene" at t h e left followed by a s e r i e s of page n u m b e r s above e a c h of which will a p p e a r t h e n a m e o r f o r m u l a of t h e o t h e r reactant a s , f o r example, propene, allyl c h l o r If t h e r e a c t i o n w a s ide, dichloropentane, that of benzene with p r o p e n e i n the p r e s e n c e of v a r i o u s c a t a l y s t s t h e heading at t h e beginning of t h e l i n e would b e "Benzene p l u s propene" and would be follolwed by t h e page n u m b e r s above e a c h of which would a p p e a r a notation c o n c e r n ing the c a t a l y s t o r t h e t e m p e r a t u r e o r o t h e r v a r i a b l e . The l a b o r a t o r y v o l u m e s a r e sufficiently s m a l l , , u s u a l l y 150 p a g e s , t h a t it is u n n e c e s s a r y t o a t t e m p t any o r d e r f o r t h e headings o t h e r than chronological. Such chronological o r d e r is e s s e n t i a l b e c a u s e t h e index e n t r i e s a r e u s u a l l y m a d e e a c h month w h e r e a s t h e notebook

51

m a y not be filled f o r s e v e r a l months. A s p e cific e x p e r i m e n t c a n be found r e a d i l y by s c a n ning the two index pages f o r the r e a c t i o n t y p e , and then looking along the p a r t i c u l a r line f o r the d e s i r e d subheading. Using the s y s t e m of n a m e s of r e a c t a n t s and c a t a l y s t s a l s o o f f e r s a s i m p l e and effective m e a n s of indexing many y e a r s of l a b o r a t o r y e x p e r i m e n t s . Such an index was begun f o r m e m o r e than ten y e a r s ago by one of m y a s s i s t a n t s . Lined 3 X 5 " c a r d s w e r e u s e d . On the f i r s t l i n e i s w r i t t e n the n a m e of one r e a c t a n t a s the heading. On subsequent l i n e s the namks of the compounds undergoing r e a c t i o n with the f i r s t compound a r e e'ntered together with a n u m b e r indicating the notebook volume number and the page n u m b e r ; for e x a m p l e , the number 2627-12 i n d i c a t e s t h a t the e x p e r i m e n t i s d e s c r i b e d on page 12 of notebook volume number 2627. A second c a r d i s p r e p a r e d in which the heading on the f i r s t line i s the n a m e of the s e c ond r e a c t a n t , the n a m e of the f i r s t r e a c t a n t i s w r i t t e n on a subsequent line together with t h e volume and page n u m b e r . This gives a c r o s s r e f e r e n c e to the e x p e r i m e n t . When a c a t a l y s t i s u s e d , the n a m e of the c a t a l y s t a p p e a r s t o g e t h e r with the n a m e of t h e second r e a c t a n t on t h e s e c a r d s and a t h i r d c a r d i s p r e p a r e d in which the c a t a l y s t n a m e i s t h e heading. After s o m e t i m e e a c h c a r d contains a number of r e f e r e n c e s and gives a rapid s u m m a r y of r e a c t i o n s c a r r i e d out with the compound o r c a t a l y s t . The c a r d s a r e a r r a n g e d i n alphabetical o r d e r by the name of the compound o r c a t a \ y s t on the f i r s t l i n e . The n o m e n c l a t u r e of t h e s e compounds i s usually the s y s t e m a t i c n a m e unl e s s the common n a m e s e e m s p r e f e r a b l e b e c a u s e it i s u s e d continually in the l a b o r a t o r y . The c a r d index has proved t o be e x t r e m e l y u s e f u l . It gives a quick a n s w e r to questions s u c h a s , "We studied the r e a c t i o n of X with Y i n the p r e s e n c e of c a t a l y s t A; have we e v e r c a r r i e d out an e x p e r i m e n t on the r e a c t i o n of X with Z under the s a m e c o n d i t i o n s ? "

a.

CO NC LUS10N In conclusion, I w i s h to point out that while the r e s e a r c h c h e m i s t often m a y not openly e x p r e s s his a p p r e c i a t i d n f o r the indexes which a r e available to h i m , he i s , when he s t o p s t o c o n s i d e r the s i t u a t i o n , r e a l l y v e r y grateful to t h e i n d e x e r . He r e a l i z e s t h a t c h e m i s t r y i s one of the b e t t e r indexed s c i e n c e s and that the i n d e x e r i s constantly s t r i v i n g to m a k e the indexes even b e t t e r . I a m s u r e that the a r t and s c i e n c e of c h e m i cal indexing will continue to m a k e beneficial progress

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