1. AN INTRODUCTION TO ATOM ECONOMY KNOCKHARDY PUBLISHING 2015 SPECIFICATIONS

2. INTRODUCTION This Powerpoint show is one of several produced to help students understand selected topics at AS and A2 level Chemistry. It is based on the requirements of the AQA and OCR specifications but is suitable for other examination boards. Individual students may use the material at home for revision purposes or it may be used for classroom teaching with an interactive white board. Accompanying notes on this, and the full range of AS and A2 topics, are available from the KNOCKHARDY SCIENCE WEBSITE at... www.knockhardy.org.uk/sci.htm KNOCKHARDY PUBLISHING ATOM ECONOMY ©HOPTON

3. ATOM ECONOMY ©HOPTON

4. ATOM ECONOMY In most reactions you only want to make one of the resulting products Atom economy is a measure of how much of the products are useful A high atom economy means that there is less waste ©HOPTON

5. ATOM ECONOMY In most reactions you only want to make one of the resulting products Atom economy is a measure of how much of the products are useful A high atom economy means that there is less waste ATOM ECONOMY ©HOPTON MOLECULAR MASS OF DESIRED PRODUCT x 100 SUM OF MOLECULAR MASSES OF ALL PRODUCTS MOLECULAR MASS OF DESIRED PRODUCT x 100 SUM OF MOLECULAR MASSES OF ALL PRODUCTS

6. WORKED CALCULATIONS ©HOPTON

7. WORKED CALCULATIONS Calculate the atom economy for the formation of 1,2-dichloroethane, C 2 H 4 C l 2 ©HOPTON Example1

8. WORKED CALCULATIONS Calculate the atom economy for the formation of 1,2-dichloroethane, C 2 H 4 C l 2 EquationC 2 H 4 + C l 2 ——> C 2 H 4 C l 2 M r 28 71 99 ©HOPTON Example1

9. WORKED CALCULATIONS Calculate the atom economy for the formation of 1,2-dichloroethane, C 2 H 4 C l 2 EquationC 2 H 4 + C l 2 ——> C 2 H 4 C l 2 M r 28 71 99 atom economy =molecular mass of C 2 H 4 C l 2 x 100 molecular mass of all products ©HOPTON Example1

10. WORKED CALCULATIONS Calculate the atom economy for the formation of 1,2-dichloroethane, C 2 H 4 C l 2 EquationC 2 H 4 + C l 2 ——> C 2 H 4 C l 2 M r 28 71 99 atom economy =molecular mass of C 2 H 4 C l 2 x 100 molecular mass of all products =99 x 100 = 100% 99 ©HOPTON An ATOM ECONOMY of 100% is typical of an ADDITION REACTION Example1

11. WORKED CALCULATIONS Calculate the atom economy for the formation of 1,2-dichloroethane, C 2 H 4 C l 2 EquationC 2 H 4 + C l 2 ——> C 2 H 4 C l 2 M r 28 71 99 atom economy =molecular mass of C 2 H 4 C l 2 x 100 molecular mass of all products =99 x 100 = 100% 99 ©HOPTON An ATOM ECONOMY of 100% is typical of an ADDITION REACTION Example1

12. WORKED CALCULATIONS Calculate the atom economy for the formation of nitrobenzene, C 6 H 5 NO 2 ©HOPTON Example2

13. WORKED CALCULATIONS Calculate the atom economy for the formation of nitrobenzene, C 6 H 5 NO 2 EquationC 6 H 6 + HNO 3 ——> C 6 H 5 NO 2 + H 2 O M r 78 63 12318 ©HOPTON An ATOM ECONOMY of 100% is not possible with a SUBSTITUTION REACTION Example2

14. WORKED CALCULATIONS Calculate the atom economy for the formation of nitrobenzene, C 6 H 5 NO 2 EquationC 6 H 6 + HNO 3 ——> C 6 H 5 NO 2 + H 2 O M r 78 63 12318 atom economy = molecular mass of C 6 H 5 NO 2 x 100 molecular mass of all products ©HOPTON Example2

15. WORKED CALCULATIONS Calculate the atom economy for the formation of nitrobenzene, C 6 H 5 NO 2 EquationC 6 H 6 + HNO 3 ——> C 6 H 5 NO 2 + H 2 O M r 78 63 12318 atom economy = molecular mass of C 6 H 5 NO 2 x 100 molecular mass of all products =123 x 100 = 87.2% 123 + 18 ©HOPTON Example2

16. WORKED CALCULATIONS Calculate the atom economy for the formation of nitrobenzene, C 6 H 5 NO 2 EquationC 6 H 6 + HNO 3 ——> C 6 H 5 NO 2 + H 2 O M r 78 63 12318 atom economy = molecular mass of C 6 H 5 NO 2 x 100 molecular mass of all products =123 x 100 = 87.2% 123 + 18 ©HOPTON An ATOM ECONOMY of 100% is not possible with a SUBSTITUTION REACTION Example2

17. WORKED CALCULATIONS Calculate the atom economy for the preparation of ammonia from the thermal decomposition of ammonium sulphate. ©HOPTON Example3

18. WORKED CALCULATIONS Calculate the atom economy for the preparation of ammonia from the thermal decomposition of ammonium sulphate. Equation(NH 4 ) 2 SO 4 ——> H 2 SO 4 + 2NH 3 M r 132 98 17 ©HOPTON Example3

19. WORKED CALCULATIONS Calculate the atom economy for the preparation of ammonia from the thermal decomposition of ammonium sulphate. Equation(NH 4 ) 2 SO 4 ——> H 2 SO 4 + 2NH 3 M r 132 98 17 atom economy = 2 x molecular mass of NH 3 x 100 molecular mass of all products ©HOPTON Example3

20. WORKED CALCULATIONS Calculate the atom economy for the preparation of ammonia from the thermal decomposition of ammonium sulphate. Equation(NH 4 ) 2 SO 4 ——> H 2 SO 4 + 2NH 3 M r 132 98 17 atom economy = 2 x molecular mass of NH 3 x 100 molecular mass of all products =2 x 17= 25.8% 98 + (2 x 17) ©HOPTON Example3

21. WORKED CALCULATIONS Calculate the atom economy for the preparation of ammonia from the thermal decomposition of ammonium sulphate. Equation(NH 4 ) 2 SO 4 ——> H 2 SO 4 + 2NH 3 M r 132 98 17 atom economy = 2 x molecular mass of NH 3 x 100 molecular mass of all products =2 x 17= 25.8% 98 + (2 x 17) ©HOPTON In industry a low ATOM ECONOMY isn’t necessarily that bad if you can use some of the other products. If this reaction was used industrially, which it isn’t, the sulphuric acid would be a very useful by-product. Example3

22. CALCULATIONS Calculate the atom economy of the following reactions (the required product is shown in red) CH 3 COC l + C 2 H 5 NH 2 ——> CH 3 CONHC 2 H 5 + HC l C 2 H 5 C l + NaOH ——> C 2 H 5 OH + NaCl C 2 H 5 C l + NaOH ——> C 2 H 4 + H 2 O + NaC l ©HOPTON

23. CALCULATIONS Calculate the atom economy of the following reactions (the required product is shown in red) CH 3 COC l + C 2 H 5 NH 2 ——> CH 3 CONHC 2 H 5 + HC l C 2 H 5 C l + NaOH ——> C 2 H 5 OH + NaCl C 2 H 5 C l + NaOH ——> C 2 H 4 + H 2 O + NaC l ©HOPTON 70.2%

24. CALCULATIONS Calculate the atom economy of the following reactions (the required product is shown in red) CH 3 COC l + C 2 H 5 NH 2 ——> CH 3 CONHC 2 H 5 + HC l C 2 H 5 C l + NaOH ——> C 2 H 5 OH + NaCl C 2 H 5 C l + NaOH ——> C 2 H 4 + H 2 O + NaC l ©HOPTON 70.2% 55.8%

25. CALCULATIONS Calculate the atom economy of the following reactions (the required product is shown in red) CH 3 COC l + C 2 H 5 NH 2 ——> CH 3 CONHC 2 H 5 + HC l C 2 H 5 C l + NaOH ——> C 2 H 5 OH + NaCl C 2 H 5 C l + NaOH ——> C 2 H 4 + H 2 O + NaC l ©HOPTON 70.2% 55.8% 33.9%

26. OVERVIEW ©HOPTON

27. OVERVIEW addition reactions will have 100% atom economy substitution reactions will have less than 100% atom economy elimination reactions will have less than 100% atom economy ©HOPTON

28. OVERVIEW addition reactions will have 100% atom economy substitution reactions will have less than 100% atom economy elimination reactions will have less than 100% atom economy high atom economy= fewer waste materials = GREENER and MORE ECONOMICAL ©HOPTON

29. OVERVIEW addition reactions will have 100% atom economy substitution reactions will have less than 100% atom economy elimination reactions will have less than 100% atom economy high atom economy= fewer waste materials = GREENER and MORE ECONOMICAL The percentage yield of a reaction must also be taken into consideration. some reactions may have a high yield but a low atom economy some reactions may have a high atom economy but a low yield ©HOPTON

30. OVERVIEW addition reactions will have 100% atom economy substitution reactions will have less than 100% atom economy elimination reactions will have less than 100% atom economy high atom economy= fewer waste materials = GREENER and MORE ECONOMICAL The percentage yield of a reaction must also be taken into consideration. some reactions may have a high yield but a low atom economy some reactions may have a high atom economy but a low yield Reactions involving equilibria must also be considered ©HOPTON

31. ©2015 JONATHAN HOPTON & KNOCKHARDY PUBLISHING THE END AN INTRODUCTION TO ATOM ECONOMY ©HOPTON