The Preparation and Refining of Cane Sugar A Laboratory Experiment' F. FROMM, College of t h e Sacred Heart, Santuree, PlqertoRieo, NICANOR QUINONES, American Cyanamid Company, Bound Brook, New Jersey, and HAUL MALDONADO, Central Aguirre, Puerto Rieo
THE emergencies of the war and especially the shortage in the supply of chemicals during the year 1942 induced the Puerto Rican educational laboratories to rely more than ever on the local supply of raw materials. The preparation and refining of cane sugar was introduced at that time into our program of organic work as an exercise in obtaining a carbohydrate as well as in performing a vacuum distillation. It has served well enough to be made a standard experiment in our organic course thereafter. The procedure may therefore be of interest to other laboratories where cane juice and crude sugar may become available again. As HessenlandZ did in the laboratory preparation of sugar from beets, we have followed closely the steps of the process in the sugar mill. To 500 cc. of cane juice such an amount of milk of lime was added that litmus would just turn blue. The mixture was allowed to settle overnight and was then filtered by suction. The 1 See (1944).
F~OMM, F.,AND P. 1. RIVERA, THISJOWAL,21, 196
2 "Praktikum der gemerblichen Chemie," J. F. Lehmanns Vedag, Munich, 1938, p. 207.
clear, brownish yellow filtrate was evaporated in vacuo a t 50 to 65°C. to a brown, very viscous sirup. It is essential to continue distillation until the sirup has reached a very high degree of viscosity and will scarcely flow, otherwise no crystallization will take place upon cooling. The hot sirup was poured into a crystallizing dish and was stored in the refrigerator until it was well crystallized for several days. The crystals were separated from the molasses by centrifugation, as filtration on a Biichner funnel was impracticable. The yield of crude, brown sugar was about 70 per cent of the amount determined polarimetrically in the juice. The refining of this crude material or of commercial crude sugar is carried out similarly but is much easier to perform. One hundred grams of brown sugar are dissolved in 90 cc. of water and treated with milk of lime as above. The yellow filtrate is heated with absorbent charcoal, filtered hot, and evaporated in vacuo a t 50 to 65'C. The brown, sirupy residue will crystallize much more quickly than the cruder material. The sugar crystals can be separated by suction on the Biichner funnel. The yield varies from 60 to 80 per cent.
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"We, thepeoples of t h e united Nations. to reafirm faith i nfundomentai h u m a n rights, i n t h e dignity and worth of t h e h u m a n person, i n the equal rights of m e n and to promote social progress and better standwomen and of nations large and small ards of life i n larger freedom, and for these ends to practice tolerance and live together i n peace w i t h one another as good neighbors have resolved t o combine our efforts to accomplish these aims."-From t h e Preamble t o the San Francisco Charter
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