JK-TK/Newdata huggingface dataset:
(i)Hydrogenation Hydrogenation is an addition reaction in which hydrogen in presence of Palladium/Nickel catalyst at 150oC temperatures react with alkynes to form alkenes then alkanes. Examples 1.During hydrogenation, two hydrogen atom in the hydrogen molecule attach itself to one carbon and the other two hydrogen to the second carbon breaking the triple bond to double the single. Chemical equation
56 HC = CH + H2 -Ni/Pa -> H2C = CH2 + H2 -Ni/Pa -> H2C - CH2 H H H H H H C = C + H – H - Ni/Pa -> H - C = C – H + H – H - Ni/Pa -> H - C - C – H H H H H H H 2.Propyne undergo hydrogenation to form Propane Chemical equation H3C CH = CH2 + 2H2 -Ni/Pa-> H3C CH - CH3 H H H H H H H C C = C + 2H – H - Ni/Pa-> H - C – C - C- H H H H H H 3(a) But-1-yne undergo hydrogenation to form Butane Chemical equation But-1-yne + Hydrogen –Ni/Pa-> Butane H3C CH2 C = CH + 2H2 -Ni/Pa-> H3C CH2CH - CH3 H H H H H H H H C C - C = C + 2H – H - Ni/Pa-> H - C- C – C - C- H H H H H H H (b) But-2-yne undergo hydrogenation to form Butane Chemical equation But-2-yne + Hydrogen –Ni/Pa-> Butane H3C C = C CH2 + 2H2 -Ni/Pa-> H3C CH2CH - CH3 H H H H H H H C C = C - C H + 2H – H- Ni/Pa-> H - C- C – C - C- H H H H H H H
57 (ii) Halogenation. Halogenation is an addition reaction in which a halogen (Fluorine, chlorine, bromine, iodine) reacts with an alkyne to form an alkene then alkane. The reaction of alkynes with halogens with alkynes is faster than with alkenes.
Chemical equation
56 HC = CH + H2 -Ni/Pa -> H2C = CH2 + H2 -Ni/Pa -> H2C - CH2 H H H H H H C = C + H – H - Ni/Pa -> H - C = C – H + H – H - Ni/Pa -> H - C - C – H H H H H H H 2.Propyne undergo hydrogenation to form Propane Chemical equation H3C CH = CH2 + 2H2 -Ni/Pa-> H3C CH - CH3 H H H H H H H C C = C + 2H – H - Ni/Pa-> H - C – C - C- H H H H H H 3(a) But-1-yne undergo hydrogenation to form Butane Chemical equation But-1-yne + Hydrogen –Ni/Pa-> Butane H3C CH2 C = CH + 2H2 -Ni/Pa-> H3C CH2CH - CH3 H H H H H H H H C C - C = C + 2H – H - Ni/Pa-> H - C- C – C - C- H H H H H H H (b) But-2-yne undergo hydrogenation to form Butane Chemical equation But-2-yne + Hydrogen –Ni/Pa-> Butane H3C C = C CH2 + 2H2 -Ni/Pa-> H3C CH2CH - CH3 H H H H H H H C C = C - C H + 2H – H- Ni/Pa-> H - C- C – C - C- H H H H H H H
57 (ii) Halogenation. Halogenation is an addition reaction in which a halogen (Fluorine, chlorine, bromine, iodine) reacts with an alkyne to form an alkene then alkane. The reaction of alkynes with halogens with alkynes is faster than with alkenes. The triple bond in the alkyne break and form a double then single bond. The colour of the halogen fades as the number of moles of the halogens remaining unreacted decreases. Two bromine atoms bond at the 1st carbon in the triple bond while the other two goes to the 2nd carbon.
The triple bond in the alkyne break and form a double then single bond. The colour of the halogen fades as the number of moles of the halogens remaining unreacted decreases. Two bromine atoms bond at the 1st carbon in the triple bond while the other two goes to the 2nd carbon. Examples 1Ethyne reacts with brown bromine vapour to form 1,1,2,2-tetrabromoethane. Chemical equation HC = CH + 2Br2 H Br2 C - CH Br2 H H H H C = C + 2Br – Br Br - C – C - Br Br Br Ethyne + Bromine 1,1,2,1-tetrabromoethane 2.Propyne reacts with chlorine to form 1,1,2,2-tetrachloropropane.
Two bromine atoms bond at the 1st carbon in the triple bond while the other two goes to the 2nd carbon. Examples 1Ethyne reacts with brown bromine vapour to form 1,1,2,2-tetrabromoethane. Chemical equation HC = CH + 2Br2 H Br2 C - CH Br2 H H H H C = C + 2Br – Br Br - C – C - Br Br Br Ethyne + Bromine 1,1,2,1-tetrabromoethane 2.Propyne reacts with chlorine to form 1,1,2,2-tetrachloropropane. Chemical equation H3C C = CH + 2Cl2 H3C CHCl2 - CHCl2 Propyne + Chlorine 1,1,2,2-tetrachloropropane H H Cl H H C C = C + 2Cl – Cl H - C – C - C- Cl H H H Cl Cl Propyne + Iodine 1,1,2,2-tetraiodopropane H3C C = CH + 2I2 H3C CHI2 - CHI2 H H H H H I H H C C - C = C + 2I – I H - C- C – C - C- I H H H H I I
58 3(a)But-1-yne undergo halogenation to form 1,1,2,2-tetraiodobutane with iodine Chemical equation But-1-yne + iodine 1,1,2,2-tetrabromobutane H3C CH2 C = CH + 2I2 H3C CH2C I2 - CHI2 H H H H I I H C C - C = C -H + 2I – I H - C- C – C - C- H H H H H H I I (b) But-2-yne undergo halogenation to form 2,2,3,3-tetrafluorobutane with fluorine But-2-yne + Fluorine 2,2,3,3-tetrafluorobutane H3C C = C -CH2 + 2F2 H3C CF2CF2 - CH3 H H H H H H H H H C C = C - C -H + F – F H - C- C – C - C- H H H H H H H 4.
Examples 1Ethyne reacts with brown bromine vapour to form 1,1,2,2-tetrabromoethane. Chemical equation HC = CH + 2Br2 H Br2 C - CH Br2 H H H H C = C + 2Br – Br Br - C – C - Br Br Br Ethyne + Bromine 1,1,2,1-tetrabromoethane 2.Propyne reacts with chlorine to form 1,1,2,2-tetrachloropropane. Chemical equation H3C C = CH + 2Cl2 H3C CHCl2 - CHCl2 Propyne + Chlorine 1,1,2,2-tetrachloropropane H H Cl H H C C = C + 2Cl – Cl H - C – C - C- Cl H H H Cl Cl Propyne + Iodine 1,1,2,2-tetraiodopropane H3C C = CH + 2I2 H3C CHI2 - CHI2 H H H H H I H H C C - C = C + 2I – I H - C- C – C - C- I H H H H I I
58 3(a)But-1-yne undergo halogenation to form 1,1,2,2-tetraiodobutane with iodine Chemical equation But-1-yne + iodine 1,1,2,2-tetrabromobutane H3C CH2 C = CH + 2I2 H3C CH2C I2 - CHI2 H H H H I I H C C - C = C -H + 2I – I H - C- C – C - C- H H H H H H I I (b) But-2-yne undergo halogenation to form 2,2,3,3-tetrafluorobutane with fluorine But-2-yne + Fluorine 2,2,3,3-tetrafluorobutane H3C C = C -CH2 + 2F2 H3C CF2CF2 - CH3 H H H H H H H H H C C = C - C -H + F – F H - C- C – C - C- H H H H H H H 4. But-1,3-diyne should undergo halogenation to form 1,1,2,3,3,4,4 octaiodobutane.
Chemical equation HC = CH + 2Br2 H Br2 C - CH Br2 H H H H C = C + 2Br – Br Br - C – C - Br Br Br Ethyne + Bromine 1,1,2,1-tetrabromoethane 2.Propyne reacts with chlorine to form 1,1,2,2-tetrachloropropane. Chemical equation H3C C = CH + 2Cl2 H3C CHCl2 - CHCl2 Propyne + Chlorine 1,1,2,2-tetrachloropropane H H Cl H H C C = C + 2Cl – Cl H - C – C - C- Cl H H H Cl Cl Propyne + Iodine 1,1,2,2-tetraiodopropane H3C C = CH + 2I2 H3C CHI2 - CHI2 H H H H H I H H C C - C = C + 2I – I H - C- C – C - C- I H H H H I I
58 3(a)But-1-yne undergo halogenation to form 1,1,2,2-tetraiodobutane with iodine Chemical equation But-1-yne + iodine 1,1,2,2-tetrabromobutane H3C CH2 C = CH + 2I2 H3C CH2C I2 - CHI2 H H H H I I H C C - C = C -H + 2I – I H - C- C – C - C- H H H H H H I I (b) But-2-yne undergo halogenation to form 2,2,3,3-tetrafluorobutane with fluorine But-2-yne + Fluorine 2,2,3,3-tetrafluorobutane H3C C = C -CH2 + 2F2 H3C CF2CF2 - CH3 H H H H H H H H H C C = C - C -H + F – F H - C- C – C - C- H H H H H H H 4. But-1,3-diyne should undergo halogenation to form 1,1,2,3,3,4,4 octaiodobutane. The reaction uses four moles of iodine molecules/eight iodine atoms to break the two(2) triple double bonds at carbon “1” and “2”.
Chemical equation H3C C = CH + 2Cl2 H3C CHCl2 - CHCl2 Propyne + Chlorine 1,1,2,2-tetrachloropropane H H Cl H H C C = C + 2Cl – Cl H - C – C - C- Cl H H H Cl Cl Propyne + Iodine 1,1,2,2-tetraiodopropane H3C C = CH + 2I2 H3C CHI2 - CHI2 H H H H H I H H C C - C = C + 2I – I H - C- C – C - C- I H H H H I I
58 3(a)But-1-yne undergo halogenation to form 1,1,2,2-tetraiodobutane with iodine Chemical equation But-1-yne + iodine 1,1,2,2-tetrabromobutane H3C CH2 C = CH + 2I2 H3C CH2C I2 - CHI2 H H H H I I H C C - C = C -H + 2I – I H - C- C – C - C- H H H H H H I I (b) But-2-yne undergo halogenation to form 2,2,3,3-tetrafluorobutane with fluorine But-2-yne + Fluorine 2,2,3,3-tetrafluorobutane H3C C = C -CH2 + 2F2 H3C CF2CF2 - CH3 H H H H H H H H H C C = C - C -H + F – F H - C- C – C - C- H H H H H H H 4. But-1,3-diyne should undergo halogenation to form 1,1,2,3,3,4,4 octaiodobutane. The reaction uses four moles of iodine molecules/eight iodine atoms to break the two(2) triple double bonds at carbon “1” and “2”. But-1,3-diene + iodine 1,2,3,4-tetraiodobutane H C = C C = C H + 4I2 H C I2 C I2 C I2 C H I2 I I I I H C C - C = C -H + 4(I – I) H - C- C – C - C- H I I I I (iii) Reaction with hydrogen halides.
But-1,3-diyne should undergo halogenation to form 1,1,2,3,3,4,4 octaiodobutane. The reaction uses four moles of iodine molecules/eight iodine atoms to break the two(2) triple double bonds at carbon “1” and “2”. But-1,3-diene + iodine 1,2,3,4-tetraiodobutane H C = C C = C H + 4I2 H C I2 C I2 C I2 C H I2 I I I I H C C - C = C -H + 4(I – I) H - C- C – C - C- H I I I I (iii) Reaction with hydrogen halides. Hydrogen halides reacts with alkyne to form a halogenoalkene then halogenoalkane. The triple bond in the alkyne break and form a double then single bond. 59 The main compound is one which the hydrogen atom bond at the carbon with more hydrogen . Examples 1. Ethyne reacts with hydrogen bromide to form bromoethane. Chemical equation H C = C H + 2HBr H3 C - CH Br2 H H H H C = C + 2H – Br H - C – C - Br H Br Ethyne + Bromine 1,1-dibromoethane 2. Propyne reacts with hydrogen iodide to form 2,2-diiodopropane (as the main product ) Chemical equation H3C C = CH + 2HI H3C CHI2 - CH3 Propene + Chlorine 2,2-dichloropropane H H I H H C C = C + 2H – I H - C – C - C- H H H H I H 3.
Ethyne reacts with hydrogen bromide to form bromoethane. Chemical equation H C = C H + 2HBr H3 C - CH Br2 H H H H C = C + 2H – Br H - C – C - Br H Br Ethyne + Bromine 1,1-dibromoethane 2. Propyne reacts with hydrogen iodide to form 2,2-diiodopropane (as the main product ) Chemical equation H3C C = CH + 2HI H3C CHI2 - CH3 Propene + Chlorine 2,2-dichloropropane H H I H H C C = C + 2H – I H - C – C - C- H H H H I H 3. Both But-1-yne and But-2-yne reacts with hydrogen bromide to form 2,2- dibromobutane Chemical equation But-1-ene + hydrogen bromide 2,2-dibromobutane H3C CH2 C = CH + 2HBr H3C CH2CHBr -CH3 H H H H Br H H C C - C = C + 2H – Br H - C- C – C - C- H H H H H H Br H Carbon atom with more Hydrogen atoms gets extra hydrogen
60 But-2-yne + Hydrogen bromide 2,2-dibromobutane H3C C = C -CH3 + 2HBr H3C CBr2CH2 - CH3 H H H Br H H H C C = C - C -H + 2Br – H H - C- C – C - C- H H H H Br H H 4. But-1,3-diene react with hydrogen iodide to form 2,3- diiodobutane. The reaction uses four moles of hydrogen iodide molecules/four iodine atoms and two hydrogen atoms to break the two double bonds.
Both But-1-yne and But-2-yne reacts with hydrogen bromide to form 2,2- dibromobutane Chemical equation But-1-ene + hydrogen bromide 2,2-dibromobutane H3C CH2 C = CH + 2HBr H3C CH2CHBr -CH3 H H H H Br H H C C - C = C + 2H – Br H - C- C – C - C- H H H H H H Br H Carbon atom with more Hydrogen atoms gets extra hydrogen
60 But-2-yne + Hydrogen bromide 2,2-dibromobutane H3C C = C -CH3 + 2HBr H3C CBr2CH2 - CH3 H H H Br H H H C C = C - C -H + 2Br – H H - C- C – C - C- H H H H Br H H 4. But-1,3-diene react with hydrogen iodide to form 2,3- diiodobutane. The reaction uses four moles of hydrogen iodide molecules/four iodine atoms and two hydrogen atoms to break the two double bonds. But-1,3-diyne + iodine 2,2,3,3-tetraiodobutane H C = C C = C H + 4HI H3C C I2 C I2 CH3 H H H I I H H C C - C = C -H + 4(H – I) H - C- C – C - C- H H I I H B.ALKANOLS(Alcohols)
61 (A) INTRODUCTION.
But-1,3-diene react with hydrogen iodide to form 2,3- diiodobutane. The reaction uses four moles of hydrogen iodide molecules/four iodine atoms and two hydrogen atoms to break the two double bonds. But-1,3-diyne + iodine 2,2,3,3-tetraiodobutane H C = C C = C H + 4HI H3C C I2 C I2 CH3 H H H I I H H C C - C = C -H + 4(H – I) H - C- C – C - C- H H I I H B.ALKANOLS(Alcohols)
61 (A) INTRODUCTION. Alkanols belong to a homologous series of organic compounds with a general formula CnH2n +1 OH and thus -OH as the functional group .The 1st ten alkanols include n General / molecular formular Structural formula IUPAC name 1 CH3OH H – C –O - H │ H Methanol 2 CH3 CH2OH C2H5 OH H H H C – C –O - H │ H H Ethanol 3 CH3 (CH2)2OH C3H7 OH H H H H C – C - C –O - H │ H H H Propanol 4 CH3 (CH2)3OH C4H9 OH H H H H H C – C - C - C –O - H │ H H H H Butanol 5 CH3(CH2)4OH C5H11 OH H H H H H H C – C - C- C- C –O - H │ H H H H H Pentanol 6 CH3(CH2)5OH C6H13 OH H H H H H H H C – C - C- C- C– C - O - H │ Hexanol
62 H H H H H H 7 CH3(CH2)6OH C7H15 OH H H H H H H H H C – C - C- C- C– C –C- O - H │ H H H H H H H Heptanol 8 CH3(CH2)7OH C8H17 OH H H H H H H H H H C – C - C- C- C– C –C- C -O - H │ H H H H H H H H Octanol 9 CH3(CH2)8OH C9H19 OH H H H H H H H H H H C – C - C- C- C– C –C- C –C- O - H │ H H H H H H H H H Nonanol 10 CH3(CH2)9OH C10H21 OH H H H H H H H H H H H C – C - C- C- C– C –C- C –C- C-O - H │ H H H H H H H H H H Decanol Alkanols like Hydrocarbons( alkanes/alkenes/alkynes) form a homologous series where: (i)general name is derived from the alkane name then ending with “-ol” (ii)the members have –OH as the fuctional group (iii)they have the same general formula represented by R-OH where R is an alkyl group.
The reaction uses four moles of hydrogen iodide molecules/four iodine atoms and two hydrogen atoms to break the two double bonds. But-1,3-diyne + iodine 2,2,3,3-tetraiodobutane H C = C C = C H + 4HI H3C C I2 C I2 CH3 H H H I I H H C C - C = C -H + 4(H – I) H - C- C – C - C- H H I I H B.ALKANOLS(Alcohols)
61 (A) INTRODUCTION. Alkanols belong to a homologous series of organic compounds with a general formula CnH2n +1 OH and thus -OH as the functional group .The 1st ten alkanols include n General / molecular formular Structural formula IUPAC name 1 CH3OH H – C –O - H │ H Methanol 2 CH3 CH2OH C2H5 OH H H H C – C –O - H │ H H Ethanol 3 CH3 (CH2)2OH C3H7 OH H H H H C – C - C –O - H │ H H H Propanol 4 CH3 (CH2)3OH C4H9 OH H H H H H C – C - C - C –O - H │ H H H H Butanol 5 CH3(CH2)4OH C5H11 OH H H H H H H C – C - C- C- C –O - H │ H H H H H Pentanol 6 CH3(CH2)5OH C6H13 OH H H H H H H H C – C - C- C- C– C - O - H │ Hexanol
62 H H H H H H 7 CH3(CH2)6OH C7H15 OH H H H H H H H H C – C - C- C- C– C –C- O - H │ H H H H H H H Heptanol 8 CH3(CH2)7OH C8H17 OH H H H H H H H H H C – C - C- C- C– C –C- C -O - H │ H H H H H H H H Octanol 9 CH3(CH2)8OH C9H19 OH H H H H H H H H H H C – C - C- C- C– C –C- C –C- O - H │ H H H H H H H H H Nonanol 10 CH3(CH2)9OH C10H21 OH H H H H H H H H H H H C – C - C- C- C– C –C- C –C- C-O - H │ H H H H H H H H H H Decanol Alkanols like Hydrocarbons( alkanes/alkenes/alkynes) form a homologous series where: (i)general name is derived from the alkane name then ending with “-ol” (ii)the members have –OH as the fuctional group (iii)they have the same general formula represented by R-OH where R is an alkyl group. (iv) each member differ by –CH2 group from the next/previous.
But-1,3-diyne + iodine 2,2,3,3-tetraiodobutane H C = C C = C H + 4HI H3C C I2 C I2 CH3 H H H I I H H C C - C = C -H + 4(H – I) H - C- C – C - C- H H I I H B.ALKANOLS(Alcohols)
61 (A) INTRODUCTION. Alkanols belong to a homologous series of organic compounds with a general formula CnH2n +1 OH and thus -OH as the functional group .The 1st ten alkanols include n General / molecular formular Structural formula IUPAC name 1 CH3OH H – C –O - H │ H Methanol 2 CH3 CH2OH C2H5 OH H H H C – C –O - H │ H H Ethanol 3 CH3 (CH2)2OH C3H7 OH H H H H C – C - C –O - H │ H H H Propanol 4 CH3 (CH2)3OH C4H9 OH H H H H H C – C - C - C –O - H │ H H H H Butanol 5 CH3(CH2)4OH C5H11 OH H H H H H H C – C - C- C- C –O - H │ H H H H H Pentanol 6 CH3(CH2)5OH C6H13 OH H H H H H H H C – C - C- C- C– C - O - H │ Hexanol
62 H H H H H H 7 CH3(CH2)6OH C7H15 OH H H H H H H H H C – C - C- C- C– C –C- O - H │ H H H H H H H Heptanol 8 CH3(CH2)7OH C8H17 OH H H H H H H H H H C – C - C- C- C– C –C- C -O - H │ H H H H H H H H Octanol 9 CH3(CH2)8OH C9H19 OH H H H H H H H H H H C – C - C- C- C– C –C- C –C- O - H │ H H H H H H H H H Nonanol 10 CH3(CH2)9OH C10H21 OH H H H H H H H H H H H C – C - C- C- C– C –C- C –C- C-O - H │ H H H H H H H H H H Decanol Alkanols like Hydrocarbons( alkanes/alkenes/alkynes) form a homologous series where: (i)general name is derived from the alkane name then ending with “-ol” (ii)the members have –OH as the fuctional group (iii)they have the same general formula represented by R-OH where R is an alkyl group. (iv) each member differ by –CH2 group from the next/previous. (v)they show a similar and gradual change in their physical properties e.g.
Alkanols belong to a homologous series of organic compounds with a general formula CnH2n +1 OH and thus -OH as the functional group .The 1st ten alkanols include n General / molecular formular Structural formula IUPAC name 1 CH3OH H – C –O - H │ H Methanol 2 CH3 CH2OH C2H5 OH H H H C – C –O - H │ H H Ethanol 3 CH3 (CH2)2OH C3H7 OH H H H H C – C - C –O - H │ H H H Propanol 4 CH3 (CH2)3OH C4H9 OH H H H H H C – C - C - C –O - H │ H H H H Butanol 5 CH3(CH2)4OH C5H11 OH H H H H H H C – C - C- C- C –O - H │ H H H H H Pentanol 6 CH3(CH2)5OH C6H13 OH H H H H H H H C – C - C- C- C– C - O - H │ Hexanol
62 H H H H H H 7 CH3(CH2)6OH C7H15 OH H H H H H H H H C – C - C- C- C– C –C- O - H │ H H H H H H H Heptanol 8 CH3(CH2)7OH C8H17 OH H H H H H H H H H C – C - C- C- C– C –C- C -O - H │ H H H H H H H H Octanol 9 CH3(CH2)8OH C9H19 OH H H H H H H H H H H C – C - C- C- C– C –C- C –C- O - H │ H H H H H H H H H Nonanol 10 CH3(CH2)9OH C10H21 OH H H H H H H H H H H H C – C - C- C- C– C –C- C –C- C-O - H │ H H H H H H H H H H Decanol Alkanols like Hydrocarbons( alkanes/alkenes/alkynes) form a homologous series where: (i)general name is derived from the alkane name then ending with “-ol” (ii)the members have –OH as the fuctional group (iii)they have the same general formula represented by R-OH where R is an alkyl group. (iv) each member differ by –CH2 group from the next/previous. (v)they show a similar and gradual change in their physical properties e.g. boiling and melting points.
(iv) each member differ by –CH2 group from the next/previous. (v)they show a similar and gradual change in their physical properties e.g. boiling and melting points. (vi)they show similar and gradual change in their chemical properties. B. ISOMERS OF ALKANOLS. 63 Alkanols exhibit both structural and position isomerism. The isomers are named by using the following basic guidelines: (i)Like alkanes , identify the longest carbon chain to be the parent name. (ii)Identify the position of the -OH functional group to give it the smallest /lowest position. (iii) Identify the type and position of the side branches. Practice examples of isomers of alkanols (i)Isomers of propanol C3H7OH CH3CH2CH2OH - Propan-1-ol OH CH3CHCH3 - Propan-2-ol Propan-2-ol and Propan-1-ol are position isomers because only the position of the –OH functional group changes. (ii)Isomers of Butanol C4H9OH CH3 CH2 CH3 CH2 OH Butan-1-ol CH3 CH2 CH CH3 OH Butan-2-ol CH3 CH3 CH3 CH3 OH 2-methylpropan-2-ol Butan-2-ol and Butan-1-ol are position isomers because only the position of the -OH functional group changes. 2-methylpropan-2-ol is both a structural and position isomers because both the position of the functional group and the arrangement of the atoms in the molecule changes.
Practice examples of isomers of alkanols (i)Isomers of propanol C3H7OH CH3CH2CH2OH - Propan-1-ol OH CH3CHCH3 - Propan-2-ol Propan-2-ol and Propan-1-ol are position isomers because only the position of the –OH functional group changes. (ii)Isomers of Butanol C4H9OH CH3 CH2 CH3 CH2 OH Butan-1-ol CH3 CH2 CH CH3 OH Butan-2-ol CH3 CH3 CH3 CH3 OH 2-methylpropan-2-ol Butan-2-ol and Butan-1-ol are position isomers because only the position of the -OH functional group changes. 2-methylpropan-2-ol is both a structural and position isomers because both the position of the functional group and the arrangement of the atoms in the molecule changes. (iii)Isomers of Pentanol C5H11OH CH3 CH2 CH2CH2CH2 OH Pentan-1-ol (Position isomer)
64 CH3 CH2 CH CH3 OH Pentan-2-ol (Position isomer) CH3 CH2 CH CH2 CH3 OH Pentan-3-ol (Position isomer) CH3 CH3 CH2 CH2 C CH3 OH 2-methylbutan-2-ol (Position /structural isomer) CH3 CH3 CH2 CH2 C CHOH CH3 2,2-dimethylbutan-1-ol (Position /structural isomer) CH3 CH3 CH2 CH C CH3 CH3 OH 2,3-dimethylbutan-1-ol (Position /structural isomer) (iv)1,2-dichloropropan-2-ol CClH2 CCl CH3 OH (v)1,2-dichloropropan-1-ol CClH2 CHCl CH2 OH
65 (vi) Ethan1,2-diol H H HOCH2CH2OH H-O - C - C – O-H H H (vii) Propan1,2,3-triol H OH H HOCH2CHOHCH2OH H-O - C- C – C – O-H H H H C. LABORATORY PREPARATION OF ALKANOLS.
2-methylpropan-2-ol is both a structural and position isomers because both the position of the functional group and the arrangement of the atoms in the molecule changes. (iii)Isomers of Pentanol C5H11OH CH3 CH2 CH2CH2CH2 OH Pentan-1-ol (Position isomer)
64 CH3 CH2 CH CH3 OH Pentan-2-ol (Position isomer) CH3 CH2 CH CH2 CH3 OH Pentan-3-ol (Position isomer) CH3 CH3 CH2 CH2 C CH3 OH 2-methylbutan-2-ol (Position /structural isomer) CH3 CH3 CH2 CH2 C CHOH CH3 2,2-dimethylbutan-1-ol (Position /structural isomer) CH3 CH3 CH2 CH C CH3 CH3 OH 2,3-dimethylbutan-1-ol (Position /structural isomer) (iv)1,2-dichloropropan-2-ol CClH2 CCl CH3 OH (v)1,2-dichloropropan-1-ol CClH2 CHCl CH2 OH
65 (vi) Ethan1,2-diol H H HOCH2CH2OH H-O - C - C – O-H H H (vii) Propan1,2,3-triol H OH H HOCH2CHOHCH2OH H-O - C- C – C – O-H H H H C. LABORATORY PREPARATION OF ALKANOLS. For decades the world over, people have been fermenting grapes juice, sugar, carbohydrates and starch to produce ethanol as a social drug for relaxation. In large amount, drinking of ethanol by mammals /human beings causes mental and physical lack of coordination. Prolonged intake of ethanol causes permanent mental and physical lack of coordination because it damages vital organs like the liver. Fermentation is the reaction where sugar is converted to alcohol/alkanol using biological catalyst/enzymes in yeast. It involves three processes: (i)Conversion of starch to maltose using the enzyme diastase.
Prolonged intake of ethanol causes permanent mental and physical lack of coordination because it damages vital organs like the liver. Fermentation is the reaction where sugar is converted to alcohol/alkanol using biological catalyst/enzymes in yeast. It involves three processes: (i)Conversion of starch to maltose using the enzyme diastase. (C6H10O5)n (s) + H2O(l) --diastase enzyme --> C12H22O11(aq) (Starch) (Maltose) (ii)Hydrolysis of Maltose to glucose using the enzyme maltase. C12H22O11(aq)+ H2O(l) -- maltase enzyme -->2 C6H12O6(aq) (Maltose) (glucose) (iii)Conversion of glucose to ethanol and carbon(IV)oxide gas using the enzyme zymase. C6H12O6(aq) -- zymase enzyme --> 2 C2H5OH(aq) + 2CO2(g) (glucose) (Ethanol) At concentration greater than 15% by volume, the ethanol produced kills the yeast enzyme stopping the reaction. 66 To increases the concentration, fractional distillation is done to produce spirits (e.g. Brandy=40% ethanol). Methanol is much more poisonous /toxic than ethanol. Taken large quantity in small quantity it causes instant blindness and liver, killing the consumer victim within hours. School laboratory preparation of ethanol from fermentation of glucose Measure 100cm3 of pure water into a conical flask. Add about five spatula end full of glucose. Stir the mixture to dissolve. Add about one spatula end full of yeast. Set up the apparatus as below. Preserve the mixture for about three days. D.PHYSICAL AND CHEMICAL PROPERTIES OF ALKANOLS Use the prepared sample above for the following experiments that shows the characteristic properties of alkanols (a) Role of yeast
67 Yeast is a single cell fungus which contains the enzyme maltase and zymase that catalyse the fermentation process. (b) Observations in lime water. A white precipitate is formed that dissolve to a colourless solution later. Lime water/Calcium hydroxide reacts with carbon(IV)0xide produced during the fermentation to form insoluble calcium carbonate and water.