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реши структурно не молекулярно

Criado em: 8 de dezembro de 2025

Respondido usando GPT-5.1 Thinking por Chat01

Pergunta

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реши структурно не молекулярно

Pensamento

Clarifying structural reactions

I’ve now resolved the reaction flow. The arrow from butane (C4H10) to nitrobutane (C4H9NO2) is clear. For each reaction in subquestion (1), I'll present the structural formulas, like:

CH3-CH3 + Br2 → CH3-CH2-Br + HBr, and so on.

For 2-methylpentane's chlorination, I’ll show structure like CH3-CH(CH3)-CH2-CH2-CH3 + Cl2 → CH3-CH(CH3)-CH2-CH2-CH2Cl.

I’ll make sure it matches the expectations for using structural chains.

Considering radical halogenation and reactions

For halogenation, I’m thinking the teacher may not focus too much on the mixture of isomers, so I’ll choose substitution at the tertiary position for clarity. With 2-methylpentane, substitution happens at C2, giving 2-chloro-2-methylpentane. I'll show the structural equations for chlorination, combustion (with O2), and nitration (with HNO3) reactions.

Considering Wurtz reaction for 2,4-dimethylpentane

For the Wurtz reaction, I’ll focus on substitution at the tertiary position. The target is 2,4-dimethylpentane, which has the carbon skeleton: CH3-CH(CH3)-CH2-CH(CH3)-CH3. The Wurtz reaction couples two haloalkanes to make this 7-carbon alkane (C7H16), though there could be side products. I'll focus on symmetrical products.

Choosing appropriate bond for Wurtz reaction

To form the branched C7 skeleton, we'll explore pairs of haloalkanes (such as 2-bromopropane, 2-bromobutane), following the Wurtz reaction. We're seeking a C-C bond in 2,4-dimethylpentane that yields simple, reasonable starting haloalkanes, possibly cutting between C3 (CH2) and C4 (CH). I'll check the options.

Confirming Wurtz reaction coupling for 2,4-dimethylpentane

I am analyzing the cleavage of 2,4-dimethylpentane considering potential Wurtz reaction paired halides. Cutting between the C3 (CH2) and C4 (CH) bonds gives fragments for isobutyl and isopropyl groups. After joining, the resulting molecules form 2,4-dimethylpentane, confirming the structure.

Summarizing reaction steps for 2,4-dimethylpentane synthesis

The reaction involves several steps using bromoalkanes:

  1. CH3–CH3 + Br2 → CH3–CH2–Br + HBr (with UV light).
  2. Wurtz coupling of 2 CH3–CH2–Br + 2Na → CH3–CH2–CH2–CH3 + 2NaBr.
  3. Halogenation to form 1-bromobutane: CH3–CH2–CH2–CH3 + Br2 → CH3–CH2–CH2–CH2–Br.
  4. Nitration of butane: CH3–CH2–CH2–CH3 + HNO3 → CH3–CH2–CH2–CH2–NO2.

Presenting chemical reactions and their structural formulas

For part 1, the equations are:

  1. For combustion: 2 CH3–CH2–CH2–CH3 + 13 O2 → 8 CO2 + 10 H2O, structurally balanced.
  2. Nitration reaction: CH3–CH(CH3)–CH2–CH2–CH3 + HNO3 → CH3–C(NO2)(CH3)–CH2–CH2–CH3 + H2O, simple coefficients.
  3. Wurtz reaction: (CH3)2CH–CH2–Br + CH3

Thought for 5m 9s

Resposta

Сделаю всё в структурном виде (цепочки CH₃–CH₂–….), без молекулярных формул типа C₆H₁₄.

1) Схема с C₂H₆, C₂H₅Br, C₄H₁₀, C₄H₉Br, C₄H₉NO₂, CO₂

1. Галогенирование этана

CH3−CH3+Br2→hvCH3−CH2−Br+HBr\mathrm{CH_3{-}CH_3 + Br_2 \xrightarrow{hv} CH_3{-}CH_2{-}Br + HBr}

2. Реакция Вюрца (получение бутана)

2 CH3−CH2−Br+2Na→CH3−CH2−CH2−CH3+2NaBr\mathrm{2\,CH_3{-}CH_2{-}Br + 2Na \rightarrow CH_3{-}CH_2{-}CH_2{-}CH_3 + 2NaBr}

3. Галогенирование бутана

(покажем, например, 1-бромбутан)

CH3−CH2−CH2−CH3+Br2→hvCH3−CH2−CH2−CH2−Br+HBr\mathrm{CH_3{-}CH_2{-}CH_2{-}CH_3 + Br_2 \xrightarrow{hv} CH_3{-}CH_2{-}CH_2{-}CH_2{-}Br + HBr}

4. Нитрование бутана (образование нитросоединения)

CH3−CH2−CH2−CH3+HNO3→tCH3−CH2−CH2−CH2−NO2+H2O\mathrm{CH_3{-}CH_2{-}CH_2{-}CH_3 + HNO_3 \xrightarrow{t} CH_3{-}CH_2{-}CH_2{-}CH_2{-}NO_2 + H_2O}

5. Сгорание бутана

Структурно:

CH3−CH2−CH2−CH3+132O2→4CO2+5H2O\mathrm{CH_3{-}CH_2{-}CH_2{-}CH_3 + \frac{13}{2}O_2 \rightarrow 4CO_2 + 5H_2O}

(или 22 бутана, чтобы не было дробей:
2 CH3−CH2−CH2−CH3+13O2→8CO2+10H2O2\,CH_3{-}CH_2{-}CH_2{-}CH_3 + 13O_2 \rightarrow 8CO_2 + 10H_2O).

2) 2-Метилпентан: реакции с Cl₂, O₂, HNO₃

Структурная формула 2-метилпентана:

CH3−CH(CH3)−CH2−CH2−CH3\mathrm{CH_3{-}CH(CH_3){-}CH_2{-}CH_2{-}CH_3}

а) Хлорирование (радикальное замещение)

Покажем замещение у третичного атома углерода (C-2):

CH3−CH(CH3)−CH2−CH2−CH3+Cl2→hvCH3−C(Cl)(CH3)−CH2−CH2−CH3+HCl\mathrm{CH_3{-}CH(CH_3){-}CH_2{-}CH_2{-}CH_3 + Cl_2 \xrightarrow{hv} CH_3{-}C(Cl)(CH_3){-}CH_2{-}CH_2{-}CH_3 + HCl}

б) Полное сгорание

CH3−CH(CH3)−CH2−CH2−CH3+192O2→6CO2+7H2O\mathrm{CH_3{-}CH(CH_3){-}CH_2{-}CH_2{-}CH_3 + \frac{19}{2}O_2 \rightarrow 6CO_2 + 7H_2O}

(или 22 молекулы:
2 CH3−CH(CH3)−CH2−CH2−CH3+19O2→12CO2+14H2O2\,CH_3{-}CH(CH_3){-}CH_2{-}CH_2{-}CH_3 + 19O_2 \rightarrow 12CO_2 + 14H_2O)

в) Нитрование азотной кислотой

CH3−CH(CH3)−CH2−CH2−CH3+HNO3→tCH3−C(NO2)(CH3)−CH2−CH2−CH3+H2O\mathrm{CH_3{-}CH(CH_3){-}CH_2{-}CH_2{-}CH_3 + HNO_3 \xrightarrow{t} CH_3{-}C(NO_2)(CH_3){-}CH_2{-}CH_2{-}CH_3 + H_2O}

(получается нитропроизводное 2-метилпентана).

3) Реакция Вюрца: получение 2,4-диметилпентана

Структурная формула целевого алкана:

CH3−CH(CH3)−CH2−CH(CH3)−CH3\mathrm{CH_3{-}CH(CH_3){-}CH_2{-}CH(CH_3){-}CH_3}

Подберём два галогеналкана, которые при Вюрце «сшиваются» по связям C–Hal:

  • 2-метил-1-бромпропан: (CH3)2CH−CH2−Br\mathrm{(CH_3)_2CH{-}CH_2{-}Br}
  • 2-бромпропан: CH3−CH(Br)−CH3\mathrm{CH_3{-}CH(Br){-}CH_3}

Реакция Вюрца (можно с Cl, я пишу с Br):

(CH3)2CH−CH2−Br+CH3−CH(Br)−CH3+2Na→\mathrm{(CH_3)_2CH{-}CH_2{-}Br + CH_3{-}CH(Br){-}CH_3 + 2Na \rightarrow} CH3−CH(CH3)−CH2−CH(CH3)−CH3+2NaBr\mathrm{CH_3{-}CH(CH_3){-}CH_2{-}CH(CH_3){-}CH_3 + 2NaBr}

Это и есть образование 2,4-диметилпентана по реакции Вюрца, записанное структурно.

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