AUGUSTIN-PIERRE DUBRUNFAUTA N EARLY SUGAR CHEMIST HEWITT G . FLETCHER, JR. Massachusetts Institute of Technology, Cambridge, Massachusetts
A
MONG the multitude of nearly forgotten founders of the modem sciences of sugar manufacturing and saccharimetry there is a t least one man whose works deserve to be better remembered and appreciated. That man is Augustin-Pierre Dnbrunfaut, the discoverer of mutarotation, of fructose, and one of the first investigators of maltose. He was born September 1, 1797, a t Lille where he first attended school and received a good classical education. Later he worked a t Lille under Drappiez and Delezenne in physics and chemistry and finally completed his education a t the Facult6 des Sciences a t Paris where he worked under such well-known chemists as Thenard, Gay-Lussac, Dulong, and Pouillet. One of his first investigations was on the diastatic action of an infusion of malt .on starch and in 1823he was awarded the gold medal of the Soci6t6 Central dlAgriculture for his paper on the saccharification of starch. From 1824 to 1830 he held a professorship in applied chemistry and physics a t a technical school in Paris. At the same period, in 1827, be founded a t Bercy, a suburb of Paris, a school for beet-sugar manufacturing. In 1830 he directed a beet-sugar factory as a school a t La Varenne-Saint Maur and a t about the same time he managed an agricultural distillery a t the Menagerie de Versailles. About the personal history of the man there seems to be little information. He was, however, known as an ardent hobbyist, having made a study df the French Revolution. During the latter part of his lifetime he attempted to collect the autographs of all the members of the Convention Nationale, and a t the time of his death the collection numbered six hundred ninety-two pieces. It is said that he liked the autograph collection the best, although i t formed but a seventh part of his collection on the French Revolution (1). During his lifetime he was very active as an industrial chemist as well as an investigator. Not only did he found a t Douai a plant for the production of alcohol from beet sugar, but he was constantly employed in writing on practical matters concerning the sugar and alcohol industries. At the comparatively early age of twenty-seven he published his "Trait6 complet de l'art de la distillation" which was indeed a "complete" work, containing in three parts a comprehensive survey of the available information. The first part dealt with the various sources of sugar and the means for preparing these materials for -fermentation, the second part treated the technic of fermentation, while the third
concerned the distillation of the alcohol formed. The work, in two volumes, includes many passages of historical interest. That Dubrunfaut had a clear and surprisingly modem understanding of political economy is evidenced by his opening remarks in this work.' "Considbr6e d'une manibre absolue, toute opbration qui change la forme des choses pour augmenter leur valeur est une v6ritable production; cousidbr6e d'une maniPre relative, c'est une
richesse d'autant plus grande pour une nation que la nouvelle production comporte plus d'importance et qu'elle s'exerce ellembme sur des productions indig&nes. Ces axiomes d'6couomie politique trouvent ici leur place naturelle. Ce sont des v6ritb incontestables que je vais consolider par des examples."
It is indeed surprising to notice Dubrunfaut's per-
I "Trait6 complet de I'Gt de la distillation," Bachelier, Paris. 1824. Vol. I. D. 1.
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spicacity when, speaking of different kinds of sugar, he says,2 "Une grand nombre d'extraits de v6g6taux peuvent aussi fournir un sucre qui se rapproche plus ou moins de l'un ou l'autre des deux espsces que nous Tenons de signaler; et quoique plusieura
best parts of the French work have been deleted while a large section of receipes for alcoholic drinks has been added. In 1825, the year after his work on distillation, his second and most important work was published. It was the "Art de fabriquer le sucre de betteraves"-a work destined to prove useful and influential in the beet sugar industry for over fifty years (2). The time was particularly ripe for this comprehensive work. Marggraf's discovery of beet sugar in 1747 had lain fallow for nearly half a century until Achard, under the royal patronage of Frederick William I1 of P ~ s s i a , founded the first beet-sugar refinery in 1802. With the Napoleonic disturbances and the consequent French need for an independent source of sugar, the beet-sugar industry in France soon assumed considerable importance which it retained after peace was finally made
PARM. DUBRUNFAUT,
TRE TITLE PAGEO F DUBRUNPAUT'S "ART DE FABRIQUER LE SUCRE DE BETTERAVES" chimistes distingubs n'admettent point d'autres nuances dans les sucres solides, que ces deux esp&s, je ne partage pas leur opinion, et je crois que le genre sucre est le chef d'une famille nombreuse."
How well later discoveries bore this out! That Dubrunfaut's work on distillation was well received is shown by the appearance in 1830 of an English translation. This was more of a practical manual It was Dubrunfaut who first gathered and ordered the than Dubrunfant's original work and lacks the good accumulated information in a organization and clarity of the original. Some of the "or an interesting account of thin book see E. 0. TON LIPPMANN,"Vor hundert Jahren IV." Deut Zuckerind.. 50, 17-18 1 Trait6 complet de l'art de la distillation," Bachelier, Paris, 1824, Vol. I. p. 245.
(Jan..1925).
In 1845 Dubrunfaut published "La vigne remplacee par la betterave pour la production des alcools"a work which is said to have had almost immediate and far-reaching effect upon the French alcohol industry (3). He himself carried out many new ideas by founding in 1858 a t Chalon-sur-SaBne a factory for the direct production of alcohol from sugar beets. Like other scientists of his time he did most of his researches with very practical ends in view. For his work on the refining of sugar by means of its barium salt he was awarded two council medals by the London Exposition of 1851. The same exposition also awarded him a First Class medal for his process of concentrating acids by distillation. He collaborated in the writing of such publications as
to hydration of the sugar, but Dubrunfaut disproved this by studying carefully the mutarotation of anhydrous and hydrated glucose (6). A truly skeptical scientist, Dubrunfaut himself was very cautious in his statements regarding the cause of mutarotation. He only supposed it to be a manifestation of an entirely general change which takes place when solids are dissolved. In support of this he showed that there is a difference between the initial and final solubilities of
l'lndustriel, Revue encyclopddique, I'Encyclopddie moderne and was editor of a number of agricultural chemical worksnotably of the Bulletin universe1 des sciences. In 1830 and 1831 he published I'Agriculteur manufacturier, one of the first important publications having
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articles on the beet-sugar industry. He also wrote considerably on the commercial applications of osmosis.' For a number of years notes and articles from his scientific investigations were published in the Comptes rendus of the French Academy of Sciences. His works may also be found in Annales de chimie et physique while translations of some of these French articles appeared in Erdmann's Journal frir Praktische
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Chemie. He was a member of numerous scientific societies and a Knight of the Legion of Honor. Dubrunfaut's most notable contributiou to organic chemistry was his discovery of mutarotation ( 4 ) . He first observed this phenomenon in 1846 during a study of the optical inversion of cane sugar as a means of analysis. Obtaining from Soleil a polarimeter, then a newly invented instrument, he began an investigation to determine the temperature coefficientsand inversion constant. Before he was well under way, however, his work was anticipated by Clerget whff published his well-known work on the inversion of sucrose. But one new thing that Dubrnnfant did observe was that freshly dissolved glucose had a rotational value twice that which Biot had observed. Later Dubrnnfaut called this phenomenon "birotation" because the final value for glucose was about half the original one ( 5 ) . As has often happened in the past with great discoveries this one made little impression upon Dubrunfaut's contemporaries. He himself continued his researches, looking for mutarotation among other sugars. The second case he studied was that of lactose where he found a change of from 8/5 to 1 (5). Always he attempted to find some simple numerical relationship between the initial and final rotations. During Dubrunfaut's lifetime many theories were advanced to explain mutarotation--a phenomenon which a t that stage of science was quite incapable of explanation. Bechamp, for instance, suggested that it might be due
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lactose (6). The true explanation of the phenomenon was not, of course, to come until the turn of the century, long after Dubrunfaut's death. Concerning the importance of the discovery of mutarotation C. S. Hudson says:"'This discovery (Tanret'sof the two forms of
DUB RUN FA^^, "L'Osmose et ses applications industriel."
Paris. 1873.
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J Am. Chem. Sor.. 32. 889 (1910)
alucose) is the complement of Dubruntaut's and the two must &use chemists the world over to be grateful t o French science, because more fruitful single discoveries in the chemistry of the carbohydrates have hardly been made."
He was a member of numerous scientific societies and a Knight of the Legion of Honor. Dubrunfaut's second most important discovery was that of fructose. He early' recognized that invert sugar was a mixture of two sugars and in 1847 he isolated (7) the insoluble lime addition compound of fructose from which on careful treatment with oxalic acid he obtained a sirup of fructose which he called "glucose 16vogyre." Later he obtained fructose from a number of fruit juices as well as by the hydrolysis of inuliu ( 8 ) . He showed the close relationship between glucose and fructose by measuring the quantities of alcohol and carbon dioxide produced by each upon fermentation. At the time there was great scepticism among scientists concerning his discovery. Over a period of years after the original work he demonstrated the procedure before a number of doubting savants, among whom were Melsens, Stas, Bussy, Kuhlmann, and Magnus (9). Finally in 1856 he carefully repeated his work on the isolation of fructose and published explicit directions for the procedure. Although he obtained fructose in an undoubted state of purity he was never able to crystallize it. From the rotations of glucose, fructose, and invert sugar be showed that the latter was an equimolecular mixture of the former two. It is somewhat odd that so keen an observer as he seems never to have observed the mutarotation of fructose, but perhaps this is explainable by the facts that he had only a sirup and that fructose is one of the most rapidly mutarotating sugars.
as one of the first Dubrunfaut should be to isolate and characterize the disaccharide maltose. DeSaussure in 1819 (10) had obtained maltose in a very doubtful state of purity, and i t is questionable whether he recognized i t as a single compound. In 1847, however, Dubrunfaut isolated a compound from the diastatic reaction of malt on starch and named i t maltose (11). Here, again, although he took the specific rotation of his product he appears to have missed completely its mutarotation. Like DeSaussure's discovery, Dubrunfaut's was completely forgotten, and it remained for O'Sullivan in 1872 (12) to rediscover this important sugar. On October 7, 1881, Dubrunfaut died a t Bercy-a renowned industrial chemist and teacher, famous for his contributions to the beet-sugar and alcohol industries of France but even himself never aware of the importance of his discovery of mutarotatiou. His burial was in harmony with the tenor of his life, for he decreed in his will that his funeral should be simple and quiet, the expenses which would have gone to the usual flowery affair to be given to the poor.# ACKNOWLEDGMENT
The writer wishes to express his sincere appreciation to Professor E. 0. von Lippmanu for his kind aid in finding a photograph of Dubrunfaut. To Professor R. C. Hockett and Professor T. L. Davis, both of the Massachusetts Institute of Technology, be also wishes to make grateful acknowledgment for innumerable kind suggestions.
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DAVIS, "Dubrunfaut and His Work, 1797-1881," Chemistry 6, Industry, 49,644 (1930). Th'iS is an excellent sketch of his life as well as a particularly valuable review of his chemical works.
GENERAL BIBLIOGRAPHY
GLAESER,"Biogrspbie nationale des contemporains," Glaeser e t Cie.. Paris, 1878, P. 203. "ON LIPPMANN. "Ge~cbichtedes Zuckers." Leipzig, 1890. P o o c ~ ~ o o n a"Biographisch-Literarisshes a, Handwhrterbuch." Barth, Leipzig bd. 3, 1898, p. 383.
"Histoire centenalle du sucre de betterave," Paris, 1 9 1 2 (le S y n d i c a t d e s f a i 3 r i c a n t s d e s u c r e d e Also those works whose title pages are reproduced.
LITERATURE CITED
(1) "Catalogue de la pr&ieuse collection d'autographies composant le cabinet de feu M. A.-P. Dubrunfaut, chimiste, officier de la Legion d'bonneur." Printed in Paris on the occasion of the public sale of this part of Dubrunfaut's estate on March 25, 1885. "Vor bundert Jahren N."Deut. Zuckerind., (2) YON LIPPMANN, SO, 19 (Jan.. 1925). (3) See Glaeser, cited above. (4) Compt. rend.. 23, 42 (1846); Ann. chim. fihys., 18, 99-107 (1846); ibid., 21, 178-80 (1847).
( 5 ) Compt. rend., 42,228 (1856). (6) bid., 42, 739 (1856). (7) Ibid., "3 308 (Ia7). .(a) Ibid., 42, 739 (1856). (9) Zbid., 42, 901 (1856). (10) Ann. ckim. phys., 11,379 (1819). (I1) Ibid., "9 17' (1847). (12) BLI..5, 485 (1872).
