ALKYNES

1. Provide an IUPAC name for each alkynes:

a) b) c) d) e)

2. Write a structural formula corresponding to each of the following:

a) 1-chloro-2,5-dimethyl-3-hexyne c) ethynylcyclopentane

b) 4-methyl-1-heptyne d) 3-ethyl-3-methyl-1-hexyne

3. Write structural formula and name products that are expected from the reaction:

1. 1-butyne, H₂ / Pt

2. 2-butyne, H₂ / Pd, Pb²⁺ (Lindlar catalyst)

3. 2-pentyne, Na / NH₃ (metal-ammonia reduction)

4. Write the structure of the major organic products isolated from the reaction of 1-butyne with:

1. NaNH₂ / NH₃

2. Product a) + 1-bromobutane

3. Product a) + 2-bromo-2-methylpropane

4. 1 mol HCl

5. 2 mol HCl

6. water / H₂SO₄, Hg²⁺

7. 1 mol Br₂

8. 2 mol Br₂

9. ozonolysis

5. Outline efficient syntheses of each of the following alkynes from acetylene and any necessary organic reagents:

1. 1-heptyne

2. 2-heptyne

3. 3-heptyne

6. How could you prepare propyne from each of the following compounds as a starting materials? You may use any necessary organic and inorganic reagents.

a) propene b) isopropyl bromide

7. Write a series of equations showing how you could prepare 1,1-dichloroethane from:

1. ethylene

2. vinyl chloride

3. vinyl bromide

8. How each of the following compounds could be converted to 2-pentyne?

1. 1-butene

2. 1,1-dichlorobutane

3. 1-chloro-1-butene

4. acetylene

9. Write structural formulas and give the names for all the alkynes of molecular formula C₅H₈. Select those that can be prepared in good yield by alkylation or dialkylation of acetylene.

10. Complete each of the following equations to show the conjugate acid and the conjugate base formed by proton transfer between the indicated species. For each reaction, specifiy whether the position of equilibrium lies to the side of reactants or products.

11. Show, by writing an appropriate series of equations, how you could prepare propyne from each of the following compounds as starting materials. You may use any necessary organic or inorganic reagents.

a) 2-propanol b) 1-propanol c) isopropyl bromide

d) 1,1-dichloroethane e) ethyl alcohol f) CaC₂

12. Write a series of equations showing how you could prepare octane from acetylene.

13.Show by writing a suitable series of equations how you could prepare each of the following compounds from the designated materials and any necessary organic or inorganic reagents.

1. 2,2-dibromopropane from 1,1-dibromopropane

2. 2,2-dibromopropane from 1,2-dibromopropane

3. 2-chloropropene from 1-bromopropene

4. 1,1,2,2-tetrachloropropane from 1,2-dichloropropane

5. 2,2-diiodobutane from acetylene and ethyl bromide

6. 1-hexene from 1-butene and acetylene

7. decane from 1-butene and acetylene

8. 1-bromo-1-butyne from 2-bromobutane

14. Compound A has the molecular formula C₁₄H₂₅Br and was obtained by reaction of sodium acetylide with 1,12-dibromo-dodecane. On treatment of compound A with sodium amide, it was converted to compound B (C₁₄H₂₄). Ozonolysis of compound B gave the Diacid HOOC-(CH₂)₁₂-COOH. Catalytic hydrogenation of compound B over Lindlar palladium gave compound C (C₁₄H₂₆), while hydrogenation over platinum gave compound D (C₁₄H₂₈). Sodium ammonia reduction of compound B gave compound E (C₁₄H₂₆). Both C and E yielded O=CH(CH₂)₁₂CH=O on ozonolysis. Assign structures to compounds A through E so as to be consistent with the observed transformations.

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