Figure 2. First screen of chromatography of inks computer simulation: "Solve the Mystery" flashes to attract anention. Figure 3. Computer-simulatedTLC plates showing separation of dyes in two Inks.
separation (Fig. 3). Both inks are run on the screen at the same time with pauses so a description of each step in the process can be described. These steps are 1) Thin layer chromatographyplates 2) Ink spots applied 3) Plates dinned in liouid 4j tiquid ri'ses up plate
5) Liquid carries ink up the plate
6) Dyes separate if ink is a mixture
7) Final separation.
The student is reminded that the dyes must have the same color and position for the inks t o be considered identical. He is then asked to give his conclusion about the case with an appropriate response being output by the computer. The promam then returns to the original screen with its flashing &&tor title. In practice the 26-in. Sony TV receiver used for the computer display positioned on a cart a t eye-level could be viewed by 20-30 people a t a time and many were content to observe somebody else going through the simulation before they moved on to the next display. This was a real advantage during esoeciallv crowded times. ?he drsplays worked well, as designed, t o handle the large crowds involved. (Spokane and the 12 other surrounding school districts in our area have over 60,000 K-12 students.j The maior asset of this chromatography display was the interest i t generated among the j&o;hLgh s&dknts. Several were interested in attempting the separations and a future display should incorpor& a-hands-on aspect using a safe solvent system. The Chromatography Mystery Program for the Apple 11, II+, and IIe with Applesoft and DOS 3.3 is available for $15. Please send check payable to G. L. Breneman with requests.
Analyncal Chemistry Program Set James K. Hardy h e University of Akron Akron. OH 44325 A series of nromams is available for use in the analvtical chemistry lah&a&ry. The Analytical Chemistry program Srt consists of e ~ e h R t a ~ i coroerams for use with a Rarilo Shack in ~ o d e l ? 1 1mode) equipped with the RSModel 111( O ~ I V 232C communications port and a t least one disk drive. Also required for three of the programs is the DAU I data sampler (see Bits & Pieces. 22). The system as designed will automatically hoot Hasic with the prowr number of files and run the .MENU proxram, which hrie.flydescribes the other srven programs inthe set and allows the user to exrcute them. The programs are as follows:
1) DATALOAD The program used to enter and store X,Y
data for use with the PLOTTER oromam. This program will plot the hest fitfo; straight-line or first- or second-order data entered with DATALOAD. A plot is produced. Printer required. 3) EXTRACT1 A simulation o f a 100-tubeCraig CounterCurrent Extractor with up ru three ION substances. Simulation of a gas chromatograph where 4) GC the user must optimize a separation of three species using a column of his own design. A program that used the DAU I for the 5) TITRATE collection of pH data during a titration. At the end of the titration, the pK, and equivalent weight is determined. 6) INTEGRAT Allows for the use of the Model 111as a GC intemator. Reauires the DAU I. 7) SPEC/RAS ~hispmgramcollects data from a scanning IIV sprrtnrphotometer.K n o w s are sawd in the file SPECIDAT. Unknown appctraare then collected and identifications made based on the SPEC/DAT file. Spectra expansion and compression as well as derivatization are also possible. Requires the DAU I. 2) PLOTTER
The program set, including program listings and instructions, information on the construction and operation of the DAU I interface, and sample runs can be ohtained directly from Project SERAPHIM.
Microcomputer-Assisted Drills in Organic Synthesis R. Barone, 8. Ribero, B. Glbert, and R. Meyer Universlte Aix Marseille Ill
Faculte des Sciences et Techniques de St. Jerome 13397 Marseille Cedex 13, France Traditionally in most colleges and universities, organic chemistry course lecture continues to he the main instructional method. T o encourage thinking and active participation we have introduced the students of the fmt-year course at the University of Aix-Marseille I11 to microcomputers as an aid to the traditional lecture. Comouters have been lareelv utilized to provide student drills :i organic chemistry ilG),but moscof the methods require expensive computers and elaborate software which are beyond the limits of the resources of most small institutions. In the last years only a few organic chemistry drills have been taught with microcomputers (9-13),but this technique is now used extensively in the introductory undergraduate chemistry course level.. Volume 62 Number 5 May 1965
411
Table 1. List of Compounds-Organlc Synthesis 1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16 17 18
ROH RCH2OH RCHOHCHZR RRCOHCHZR RCHOHR RCOOH RCH2COOH RCHZCOX RCOX RCOOR' RCHO RCH2CHO RCOCWR RCOR RNH2 RCH2NH2 RCONH2 RCHZCONHS
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 34 36
Table 2.
RCN RH RCH3 RCHXHZR RCWHR RC#CR RX RCHXCHXR RCH2X RMGX RCHZMGX C02 RN02 RCHZCHPOH RCHPCOOR' RCH2CN ROR' RCOHRR
We have developed three programs entitled REVISION, ONESTEP, and MULTISTEP. These programs use an interconversion matrix of compounds similar to those previously described (3,5): the transformation between two compounds i and j is represented as the ijthelement of thematrix and the numerical value of that element is the code number of the reaction needed to effect the change of i to j. There are now 36 comnounds in the matrix. Since the molecules are renresented by a linear string of characters, only aliphatic compounds are available. Cyclizations or aromatic synthesis do not fit in this program. The list of the compounds is given in Table 1. The 38 reaction conditions are also determined bv an interconversion matrix using 51 reagents (Table 2). The interconversion matrices are used by the three programs and incorporate the main reactions encountered in our introductory organic course. In the program REVIEW a compound is designated randomly. The student attempts to input all precursors for each product. Then the student is asked to indicate the reaction conditions. The computer displays all forgotten precursors. ONESTEP is very similar to the program descrihed hy Clark (3): two products are chosen randomly by the computer and the student must indicate if the interconversion is possible. If yes, the reaction conditions are requested. MULTISTEP allows the student to simulate multi-step synthesis. When MULTISTEP is initiated the starting compound and the target are randomly selected. Then the computer searches the possible ways from the starting comoound to the tareet " bv.examining all the uossibilities of the kmconversion matrix. Thii part ;of the program was too slow in Basic: about 30 s. denendine on the number of steos of t h ~ synthesis. With cokpiied as& the time decreases'to 6.7 s Therefore. this Dart has been rewritten in 6502 assembh language and the synthesis is nuw found instantaneously. . The cumputer asks if the svnthesis is oossible. If ves. thg student must complete the synthesis in orier to progr& fron the starting comclound to the target. Then the comuuter rorrtrts rarh step of the student's answer and gives the o p portunity to work the problem again. When the student has tried all ideas the computer displays the shortest synthes~sm d asks the student if he or she wants to see all other possibilities. For the three programs the list of compounds and/or reagents available may be viewed by typing H (for Help) or hy pressing the Arrow keys, in this case the compounds are shown one by one. For the reaction conditions synonyms are accepted, the student may type, for example, H+, H30+, or H2S04. A very simple program allows additions, deletions, or modifications of the reactions. reaeents. and reaction conditions. I t also allows one to list all possible information, such ~~~~
412
Journal of Chemical Education
~
Reaction Conditions-Organic Synthesls
20=03/H20/ZN/ 21 = NAHCO3 H+ / A W T S RN=C=NR / DMSO / 3 = H2S04 H30+ H+ I 22 = HG++ / H30+ H+ 1 4 = H2S04 H30+ H+ 1 NAN3 / 23 = HZ / DEACTIVATED PD / 5 = LIALHA H2 1 24=CN/ 6=AG+/CCL4/X2/ 25=MG/ET20/ 7 =NH3/ 26 = RC#CH / NANH2 I 8 = R'OH / H2S04 H30+ H+ / 27 = NAOH OH-- STRONG BASE / NANH2 / 9=soCL2/ 28 = CH20 / ET20 / H20 H30+ / 10 = NAN3 / HZ0 / HEAT / 29 = C02 / ET20 / H20 H30 / 11 = RCH2MGX / ET20 / HZ0 30 = RCHO / ET20 / H20 H30+ 1 H30+ / 12 = RMGX 1 ET20 / HZ0 H30+ 1 13 = RCOOH / H2S04 H30+ 32 = RCHXHO / ET20 / H20 H30+ 1 H+ / 14 = ZN HG 1 H2S04 H30+ H+ HX / 15=H2/NI/ 34 = RCH-PPH3+ R C W P H 3 / 16 = NAOH OH- / X2 1 35 = RCOR 1 ET20 1 H20 H30+ / 17 = H20 H30+ / 36 = R'OH / 18 = SOCL2 / HZ0 1 HX / 37 = R'X / 3R=X9/
as precursors of a compound, reactions or all syntheses of a oroduct, sequences of reactions, and so on. There are 100 ;nrstep reactions coded. From these 100 reactions 695 s p t h ~ s e s a r eobtained and totallv thereare 5789 uroblems if we count all the possible ways f i r a determined synthesis. For example the prohlem
-
RX RCOOH has two solutions in two stem. but the oroeram . .. mav. orovide . other ways that are chemic&y longer and less interesting. The programs are written in Applesoft Basicand 6.502 assembly language. They run on an 48 K AI'I'LE 11 PLIJS microcomputer with onedisk drive. All promots are in English. Documentation may he obtained free upon request. Alternatively a copy of the programs on disk can be provided. Acknowledgment One of us (R.B.) is grateful t o Ministere des Universites (Bureau des Techniques Nouvelles d'Enseianement) for financial support.
An ln*roduction to Conformational Analysis
of Ethane and Butane Patrlck Flash Kent State University-Ashtabula Campus Ashtabula. OH 44004 Drawine and visualizine two-dimensional renresentations as three-dimensional mol~culesis a skill that i s h p o r t a n t for organic chemistry students, particularly when conformational analysis is encountered. In order to make the introduction to this area of chemistrv seem less formidable and to orovide a novel pedagogical approach to the subject, I have developed a set of computer promams that introduces the student to some conventions $01 drawing molecules and then provides brief tutorial and extensive drill work on the conformations of ethane and butane. There are five programs in the set. The first program introduces the student to the idea of honds heingrepresented by solid lines, wedges, and either dotted or barred lines depending on whether the bond is in the plane of the drawing or projecting f or backward. The how the methane ~ r o m a mthen uses these idms a
m
