AN INTRODUCTION TOAN INTRODUCTION TO

ATOM ECONOMYATOM ECONOMY

KNOCKHARDY PUBLISHINGKNOCKHARDY PUBLISHING2008 2008

SPECIFICATIONSSPECIFICATIONS©HOPTON

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 PUBLISHINGKNOCKHARDY PUBLISHING

ATOM ECONOMYATOM ECONOMY

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All diagrams and animations in this Powerpoint are original and created by Jonathan Hopton. Permission must be obtained for their use in any commercial work.

All diagrams and animations in this Powerpoint are original and created by Jonathan Hopton. Permission must be obtained for their use in any commercial work.

ATOM ECONOMYATOM ECONOMY

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ATOM ECONOMYATOM 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

ATOM ECONOMYATOM 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 ATOM ECONOMY

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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

WORKED CALCULATIONSWORKED CALCULATIONS

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WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the formation of 1,2-dichloroethane, C2H4Cl2

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Example 1Example 1

WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the formation of 1,2-dichloroethane, C2H4Cl2

Equation C2H4 + Cl2 ——> C2H4Cl2

Mr 28 71 99

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Example 1Example 1

WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the formation of 1,2-dichloroethane, C2H4Cl2

Equation C2H4 + Cl2 ——> C2H4Cl2

Mr 28 71 99

atom economy = molecular mass of C2H4Cl2 x 100

molecular mass of all products

©HOPTON

Example 1Example 1

WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the formation of 1,2-dichloroethane, C2H4Cl2

Equation C2H4 + Cl2 ——> C2H4Cl2

Mr 28 71 99

atom economy = molecular mass of C2H4Cl2 x 100

molecular mass of all products

= 99 x 100 = 100%

99

©HOPTON

An ATOM ECONOMY of 100% is typical of an ADDITION REACTION

An ATOM ECONOMY of 100% is typical of an ADDITION REACTION

Example 1Example 1

WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the formation of 1,2-dichloroethane, C2H4Cl2

Equation C2H4 + Cl2 ——> C2H4Cl2

Mr 28 71 99

atom economy = molecular mass of C2H4Cl2 x 100

molecular mass of all products

= 99 x 100 = 100%

99

©HOPTON

An ATOM ECONOMY of 100% is typical of an ADDITION REACTION

An ATOM ECONOMY of 100% is typical of an ADDITION REACTION

Example 1Example 1

WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the formation of nitrobenzene, C6H5NO2

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Example 2Example 2

WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the formation of nitrobenzene, C6H5NO2

Equation C6H6 + HNO3 ——> C6H5NO2 + H2O

Mr 78 63 123 18

©HOPTON

An ATOM ECONOMY of 100% is not possible with a SUBSTITUTION REACTION

An ATOM ECONOMY of 100% is not possible with a SUBSTITUTION REACTION

Example 2Example 2

WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the formation of nitrobenzene, C6H5NO2

Equation C6H6 + HNO3 ——> C6H5NO2 + H2O

Mr 78 63 123 18

atom economy = molecular mass of C6H5NO2 x 100

molecular mass of all products

©HOPTON

Example 2Example 2

WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the formation of nitrobenzene, C6H5NO2

Equation C6H6 + HNO3 ——> C6H5NO2 + H2O

Mr 78 63 123 18

atom economy = molecular mass of C6H5NO2 x 100

molecular mass of all products

= 123 x 100 = 87.2%

123 + 18

©HOPTON

Example 2Example 2

WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the formation of nitrobenzene, C6H5NO2

Equation C6H6 + HNO3 ——> C6H5NO2 + H2O

Mr 78 63 123 18

atom economy = molecular mass of C6H5NO2 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

An ATOM ECONOMY of 100% is not possible with a SUBSTITUTION REACTION

Example 2Example 2

WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the preparation of ammonia from the thermal decomposition of ammonium sulphate.

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Example 3Example 3

WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the preparation of ammonia from the thermal decomposition of ammonium sulphate.

Equation (NH4)2SO4 ——> H2SO4 + 2NH3

Mr 132 98 17

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Example 3Example 3

WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the preparation of ammonia from the thermal decomposition of ammonium sulphate.

Equation (NH4)2SO4 ——> H2SO4 + 2NH3

Mr 132 98 17

atom economy = 2 x molecular mass of NH3 x 100

molecular mass of all products

©HOPTON

Example 3Example 3

WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the preparation of ammonia from the thermal decomposition of ammonium sulphate.

Equation (NH4)2SO4 ——> H2SO4 + 2NH3

Mr 132 98 17

atom economy = 2 x molecular mass of NH3 x 100

molecular mass of all products

= 2 x 17 = 25.8%

98 + (2 x 17)

©HOPTON

Example 3Example 3

WORKED CALCULATIONSWORKED CALCULATIONS

Calculate the atom economy for the preparation of ammonia from the thermal decomposition of ammonium sulphate.

Equation (NH4)2SO4 ——> H2SO4 + 2NH3

Mr 132 98 17

atom economy = 2 x molecular mass of NH3 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.

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.

Example 3Example 3

CALCULATIONSCALCULATIONS

Calculate the atom economy of the following reactions (the required product is shown in red)

• CH3COCl + C2H5NH2 ——> CH3CONHC2H5 + HCl

• C2H5Cl + NaOH ——> C2H5OH + NaCl

• C2H5Cl + NaOH ——> C2H4 + H2O + NaCl

©HOPTON

CALCULATIONSCALCULATIONS

Calculate the atom economy of the following reactions (the required product is shown in red)

• CH3COCl + C2H5NH2 ——> CH3CONHC2H5 + HCl

• C2H5Cl + NaOH ——> C2H5OH + NaCl

• C2H5Cl + NaOH ——> C2H4 + H2O + NaCl

©HOPTON

70.2%70.2%

CALCULATIONSCALCULATIONS

Calculate the atom economy of the following reactions (the required product is shown in red)

• CH3COCl + C2H5NH2 ——> CH3CONHC2H5 + HCl

• C2H5Cl + NaOH ——> C2H5OH + NaCl

• C2H5Cl + NaOH ——> C2H4 + H2O + NaCl

©HOPTON

70.2%70.2%

55.8%55.8%

CALCULATIONSCALCULATIONS

Calculate the atom economy of the following reactions (the required product is shown in red)

• CH3COCl + C2H5NH2 ——> CH3CONHC2H5 + HCl

• C2H5Cl + NaOH ——> C2H5OH + NaCl

• C2H5Cl + NaOH ——> C2H4 + H2O + NaCl

©HOPTON

70.2%70.2%

55.8%55.8%

33.9%33.9%

OVERVIEWOVERVIEW

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OVERVIEWOVERVIEW

• 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

OVERVIEWOVERVIEW

• 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

OVERVIEWOVERVIEW

• 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

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OVERVIEWOVERVIEW

• 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

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©2011 JONATHAN HOPTON & KNOCKHARDY PUBLISHING©2011 JONATHAN HOPTON & KNOCKHARDY PUBLISHING

THE ENDTHE END

AN INTRODUCTION TOAN INTRODUCTION TO

ATOM ECONOMYATOM ECONOMY

©HOPTON