Article pubs.acs.org/jchemeduc
Using a Web Application To Conduct and Investigate Syntheses of Methyl Orange Remotely Lisette van Rens,†,* Hans van Dijk,‡ Jan Mulder,‡ and Pieter Nieuwland§ †
Department of Research and Theory in Education, VU University Amsterdam, The Netherlands 1081 HV Faculty of Sciences, VU University Amsterdam, The Netherlands § FutureChemistry, Nijmegen 6525 EC, The Netherlands ‡
S Supporting Information *
ABSTRACT: Thirty-six pre-university chemistry students and two chemistry teachers used flow chemistry as a technology for the synthesis of methyl orange. FutureChemistry and VU University Amsterdam cooperatively created FlowStart Remote, a device that enabled the students to remotely conduct this synthesis and in real time monitor and control the device via a LabVIEW Web application. The students were able to conduct experiments under different conditions and became acquainted with flow chemistry in a safe way. The remotely controlled device can be shared among several upper-level secondary schools, giving access to experimentation for many students all over the world.
KEYWORDS: High School/Introductory Chemistry, First-Year Undergraduate/General, Laboratory Instruction, Organic Chemistry, Inquiry-Based/Discovery Learning, Internet/Web-Based Learning, Amines/Ammonium Compounds, Laboratory Equipment/Apparatus, Synthesis, UV-Vis Spectroscopy
I
nitrosonium ions react with the amino group of the sulfanilic acid, creating a diazonium salt. The diazonium salt reacts with N,N-dimethylaniline and hydroxide ions to form methyl orange (Scheme1).
n the past decade, much has been published on Web-based applications for chemical education. Some examples of these applications include interactive visualization of materials and molecules, Wikis, Podcasts, open as well as interactive instructional resources, and chemical apps for smart phones.1−8 With today’s technology, the toolbox for Web and computerbased learning can be expanded by students who conduct an online experimental inquiry. VU University Amsterdam, developed, in collaboration with FutureChemistry, a Web experiment for the organic synthesis of methyl orange. This experiment can be conducted by pre-university chemistry students from all over the world considering that many nowadays have access to the Internet. In the Web experiment, the students can remotely handle an experimental setup that is permanently hosted in a fume hood in one of the laboratories in the faculty of chemistry at VU University Amsterdam. They can investigate and optimize the conditions for the synthesis of methyl orange, challenging themselves to reach a high yield of methyl orange. Moreover, they can accurately follow the progress of the experiment with spectroscopy and webcams.
■
WHY A WEB EXPERIMENT FOR THE SYNTHESIS OF METHYL ORANGE Under normal circumstances, the synthesis of methyl orange requires cooling with ice, because the diazonium coupling is an exothermic reaction and as such it is potentially an explosive reaction when cooling is insufficient. To handle the problem of Scheme 1. The Synthesis of Methyl Orange
■
THE SYNTHESIS OF METHYL ORANGE The synthesis of methyl orange is an exothermic reaction. Sulfanilic acid reacts with sodium carbonate, making the acid more soluble. Then, sodium nitrite and hydrochloric acid react to produce water and (NO+) or nitrosonium ions. These © 2013 American Chemical Society and Division of Chemical Education, Inc.
Published: April 4, 2013 574
dx.doi.org/10.1021/ed300719q | J. Chem. Educ. 2013, 90, 574−577
Journal of Chemical Education
Article
Figure 1. The control panel for the students.
Figure 2. Microreactor with the inlets A, B and C, temperature control and the outlet. Note that sodium carbonate is not shown and sulfanilic acid is shown in a basic form.
■
THE WEB EXPERIMENT The Web experiment can only be approached by one computer at a specified time. A procedure is developed so that a student or a small group of students can register and book experimental time for 1 h. In this hour, students can monitor and control the Web experiment using a thin client application that binds the data from the LabVIEW application to the in Microsoft Silverlight developed Web-based user interface. To make a reservation in this Web-based user interface, a Microsoft Silverlight plug-in for the Web browser is needed. After registration, the students get a password to login and conduct the Web experiment during the reserved time (e.g., next week on Thursday from 09.00−10.00 h.) When the students are logged in, they see a control panel of the experimental setup to control and monitor their measurements (Figure 1). With this panel, the students can open the valves 1, 2, and 3 and, respectively, fill the syringes with reagents A, B, and C and select their flow rates. These syringes
explosive reactions in general, researchers at universities and in research and development departments of the chemical industry often carefully study these type of reactions in a microreactor before scaling up the process. Using this technology, students also investigate the reaction conditions of the synthesis of methyl orange in a microreactor. Moreover, both the diazonium salt and the methyl orange are toxic substances; as such, this synthesis is not a preferable one for students to do in laboratories in upper-level secondary schools. Hence, a Web experiment is an option for reactions that are too dangerous, radioactive, or toxic for students to conduct in school laboratories. This also applies when chemistry departments in schools do not have the appropriate equipment. Another problem arises when substances that are required for a reaction are expensive. In pre-university chemistry education, these problems are often solved by the teacher employing a real or virtual demonstration. Or sometimes students conduct those experiments on a microscale.9 575
dx.doi.org/10.1021/ed300719q | J. Chem. Educ. 2013, 90, 574−577
Journal of Chemical Education
Article
between 400 and 650 nm is detected. The extent of transparency is by means of software translated into millimole per microliter (mmol/μL). The students can test multiple reaction conditions during the 1-h experimenting time and download the data in an Excel document on their computer with which they can determine the flow rate or yield of methyl orange.
are connected with the microreactor where the synthesis of methyl orange occurs. The microreactor10 has three inlets and one outlet (Figure 2). The required solutions A, B, and C for the synthesis, respectively, are a solution of sodium carbonate, sulfanilic acid, and sodium nitrite (inlet A); a solution of N,Ndimethylaniline and hydrochloric acid (inlet B); and a solution of sodium hydroxide for quenching the reaction process (inlet C). Moreover, the students can control the temperature of the microreactor between 8 and 80 °C, a safe temperature range for the microreactor taking into account that the synthesis of methyl orange is an exothermic reaction. After pressing the buttons “Dispense”, the students can follow the dispensing action of the three syringes with a “webcam controller” (see Figure 1 and 3).10
■
PILOT PROJECT Thirty-six pre-university students, in 15 groups of two or three, tested the whole setup of the Web experiment. These students were from two different upper-level secondary schools in The Netherlands. The project was part of their chemistry curriculum that requires a practical assessment task of about eight periods in their pre-university program. Two experienced (more than 10 years chemistry teaching) and first-degree chemistry teachers were involved in the project. These teachers also participated in the development of the teaching and learning materials. In their groups, the students first read about the use of methyl orange as an azo dye in the textile industry. This was followed by a teacher demonstration to show what happens when a few drops of methyl orange are added to a basic and acidic solution. Students then searched for information on the Internet to explain the difference in color of methyl orange in a basic and acidic solution. From this they learned that methyl orange also is a pH indicator. Next, the teacher instructed the groups to use a model kit or ChemDraw to build the molecular structures of sulfanilic acid and methyl orange. Then, they drew these structures and found their molecular formulas and masses. After this, the teacher coached the students to evaluate the accuracy, reliability, and validity of an article on the Synthesis of Methyl Orange in a Microreactor prepared by the author (L.v.R.) and a group of five experienced pre-university chemistry teachers.11 This evaluation created student understanding of the conditions that are required for the synthesis of methyl orange. Moreover, the students formulated their own inquiry question and worked out an inquiry plan on how to synthesize a higher yield of methyl orange in the microreactor. The students influenced the synthesis of methyl orange using various variables. They varied the temperature in the microreactor and the flow rates of the reagents A, B, and C. Students manipulated the variables that determine the synthesis of methyl orange and investigated questions such as: What happens with low flow rates of reagents at different temperatures? What happens to the yield of methyl orange when the flow rates are increased? The teachers discussed the groups’ inquiry plans and made, when necessary, suggestions for improvement. Subsequently, the various groups booked experimental time and conducted the planned experiments. The student groups then wrote an initial article that underwent a teacher-coordinated peer review where each group wrote a review on a peer’s article. With the received review, the groups then improved their initial article. The teacher assessed the articles to give all groups a mark as part of their practical work in the school exam. As a class inquiry community, the various groups decided on which student article(s) to send to the university faculty for publication. All submitted articles were read and assessed by the university faculty and the student group who developed the best inquiry received an inquiry reward. Moreover, their
Figure 3. Three webcams respectively show (top left) the dispense of the syringes with valves (V1, reagent A; V2, reagent B; and V3, reagent C); (top right) the synthesis of methyl orange in the microreactor; and (bottom) the product of the experiment.
As soon as the reaction starts, the microreactor colors orange-brown and the production of methyl orange can be made visible by the students with the button “webcam reactor” (Figure 1 and 3). The synthesized methyl orange dissolved in ethanol leaves the microreactor via the outlet (Figure 2), is collected in an Erlenmeyer flask and can be followed with the button “webcam product” (see Figure 1 and 3). Before the methyl orange solution is collected in the flask, it is detected in an UV−vis flow cell. LED light is used with a spectrometer so the transparency of the solution can be measured (Figure 4). For this application, the LED light
Figure 4. UV−vis flow cell for the detection of methyl orange. 576
dx.doi.org/10.1021/ed300719q | J. Chem. Educ. 2013, 90, 574−577
Journal of Chemical Education
■
article12 became part of the teaching and learning materials on the Web site for the online chemistry experiment.13
Article
SUMMARY Students control the feed rates and temperature in real time, while the product is analyzed by UV−vis spectroscopy. They immediately see the results of changing feed rates or temperature and learn to experiment with different conditions. In this way, the students become acquainted with flow chemistry in a safe way. The device is remotely controlled and therefore can be shared among several upper-level secondary schools, giving access to chemical experimentation for hundreds of students who can use their own time slot for experimentation.
■
TEACHING LEARNING MATERIALS To give all pre-university chemistry teachers and students access to and a good start with the Web experiment, a Web site was launched.13 This Web site describes the setup of the experiment and the way it is hosted in the laboratory hood of the faculty of chemistry at VU University (Figure 5). It also
■
ASSOCIATED CONTENT
S Supporting Information *
Student workbook and student article. This material is available via the Internet at http://pubs.acs.org.
■
AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Notes
The authors declare no competing financial interest.
■
Figure 5. The setup of the chemistry experiment.
ACKNOWLEDGMENTS The design and launching of the web experiment has been supported by the science faculty of VU University Amsterdam with grants from SNS, sector plan money Chemistry & Physics, as well as the Foundation for Improvement of Education and Research at VU University Amsterdam.
provides a direct link to the real experiment via the three available webcams. Moreover, it contains the student materials as a workbook with the article of the winning group from the pilot project and a teacher’s guide. These materials support two possible approaches: one as an activity for a whole class and one as an individual student activity. Furthermore, a manual with information on the organic synthesis of methyl orange and on how to handle the Web experiment also is downloadable. All participating students are challenged to improve the yield of methyl orange and submit an article on their inquiry. If a better student article is written than the one that is now on the site and submitted to the authors, the current one will be replaced.
■
REFERENCES
(1) Ong, E. W.; Razdan, A.; Garcia, A. A.; Pizziconi, V. B.; Ramakrishna, B. L.; Glaunsinger, W. S. J. Chem. Educ. 2000, 77, 1114− 1115. (2) Evans, M. J.; Moore, J. S. J. Chem. Educ. 2011, 88, 764−768. (3) Belford, R. E.; Hanson, R. M. J. Chem. Educ. 2006, 83, 1592− 1593. (4) Meyer, D. E.; Sargent, A. L. J. Chem. Educ. 2007, 84, 1551−1552. (5) Muzyka, J. L.; Kaster, I. M.; Hatcher, L. W. J. Chem. Educ. 2007, 84, 1871−1872. (6) Gutow, J. H. J. Chem. Educ. 2010, 87, 652−653. (7) Usher, K. C.; Barrette-Ng, I. H. J. Chem. Educ. 2012, 89, 555− 556. (8) Williams, A. J.; Pence, H. E. J. Chem. Educ. 2011, 88, 683−686. (9) Skinner, J. Microscale Chemistry; The Royal Society of Chemistry: London, 1997; ISBN: 1870343492. (10) Microreactor and controller were developed and built by: www. futurechemistry.com (accessed Mar 2013) (11) Van Rens, L.; Pilot, A.; Van der Schee, J. J. Res. Sci. Teach. 2010, 47, 788−806. (12) Haenen, G.; Van Harmelen, M.; Oortwijk. Y. Synthesis of methyl orange in a micro reactor, 2012. Available at: http://www. chem.vu.nl/en/Images/Article_tcm66-278718.pdf (accessed Mar 2013) (13) Chemistry experiment: www.chem.vu.nl/en/voor-het-vwo/ scheikunde-experiment (accessed Mar 2013)
■
EXPERIENCES OF STUDENTS AND TEACHERS Students were enthusiastic about the Web experiment. Some written comments were: • We like clean hands, but also real-time experiments. • It feels like a surgeon who does surgeries with a computer. • We couldn’t start the robot. During the time of the latter comment, the registration system had some bugs, so the feedback of the students was used to remove those bugs and make the system more reliable. The two teachers saw advantages as well. They verbally expressed it as • An organic synthesis is quite difficult to realize in chemistry lessons in school, so it is exciting to have one. • The students also practice inferring data which is also something that is difficult to realize. • The assistant who supports practical work of students can do other things for the department when students do not work in the school lab. • The Web experiment does not require chemicals so it saves money for our chemistry department. • Even without chemicals students can do a practical assessment task. 577
dx.doi.org/10.1021/ed300719q | J. Chem. Educ. 2013, 90, 574−577
