Pares libres de nitrógeno, carga y enlaces poliméricos
Introducido| English | Significado |
|---|---|
| amine/ˈæmaɪn/ | amina |
| zwitterion/zwɪˈtɪərɪən/ | zwitterión |
| polyamide/ˌpɒlɪˈeɪmaɪd/ | poliamida |
| hydrogen bonds/ˈhaɪdrədʒn bɒndz/ | puentes de hidrógeno |
Follow the nitrogen lone pair
- An amine 胺 accepts H⁺ through its nitrogen lone pair. Alkyl groups generally increase electron density and basicity relative to ammonia.
- In phenylamine, interaction with the ring makes the lone pair less available. Its basicity is lower.
Keep the nitrile carbon
- Reducing propanenitrile with LiAlH₄ in dry ether then work-up gives propan-1-amine. The nitrile carbon remains in the chain.
- Nitrobenzene instead needs Sn/HCl to make phenylammonium salt; alkali then releases phenylamine.
¿Cuántos átomos de carbono permanecen cuando la propanonitrilo se reduce a una amina?
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Los tres carbonos, incluido el carbono del grupo nitrilo, permanecen.
Track both amino-acid groups
- A zwitterion 两性离子 has NH₃⁺ and COO⁻ groups and zero net charge. In strong acid, COO⁻ becomes COOH.
- In strong alkali, NH₃⁺ becomes NH₂ while COO⁻ remains. Glycine is achiral because its central carbon has two H atoms.
Glycine’s alkaline form is H₂NCH₂COO⁻, with net charge −1, not the zero-charge zwitterion.
¿Cuál es la forma principal de la glicina en base fuerte?
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La base elimina el protón amónico mientras el grupo carboxilo permanece desprotonado.
La glicina es aquiral porque el carbono central tiene dos _____ átomos idénticos.
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Dos sustituyentes de hidrógeno idénticos impiden un centro quiral de cuatro grupos diferentes.
Locate the polymer backbone
- A polyamide 聚酰胺 has –C(=O)–NH– links in its backbone. Condensation produces those links and a small molecule.
- Poly(propenamide) instead opens C=C by addition. Its amide side groups do not make the reaction condensation.
Todo polímero con un grupo lateral amida se forma por condensación.
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El poli(propenamida) es un polímero de adición con grupos laterales de amida.
Explain properties through interactions
- Polyamide N–H and C=O groups form hydrogen bonds 氢键 between chains. These help hold fibres together.
- Poly(ethenol) OH groups hydrogen-bond to water, supporting suitable water-soluble laundry-bag applications.
The presence of an amide group alone does not classify the polymerisation route.
Locate the nitrogen lone pair and its availability before comparing bases. Read the actual reacting groups and links to distinguish addition from condensation polymerisation.
¿Qué dos grupos forman puentes de hidrógeno entre cadenas de poliamida?
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El grupo N–H puede donar y el oxígeno carbonílico puede aceptar puentes de hidrógeno.