Тест Байльштейна на галогены

Обнаружение атомов галогенов в органических соединениях с помощью медной проволоки

Qualitative Analysis Beginner (Middle School) 25 мин ~$5,00

Цель

Определить, содержит ли органическое соединение атомы галогенов (Cl, Br, I), с помощью теста Байльштейна с медной проволокой.

Предпосылки

The Beilstein test is a simple qualitative test for halogens in organic compounds. A copper wire is heated in a flame to form copper(II) oxide, then dipped in the test substance and returned to the flame. If a halogen is present, volatile copper halide forms and imparts a green or blue-green color to the flame. The test is sensitive but not specific (it does not distinguish between Cl, Br, and I, and can give false positives with some nitrogen compounds).

Предупреждения по безопасности

  • Chloroform is toxic — avoid inhalation and skin contact
  • Work in a fume hood when testing volatile organics
  • Hot copper wire can cause burns
  • Keep flammable solvents away from the flame

Требуемые СИЗ

goggles gloves lab_coat

Материалы

  • Copper wire (20 gauge) (15 cm)
    Make a small loop at one end
  • Chloroform (CHCl₃) (2 mL)
    Positive control
  • Ethanol (C₂H₅OH) (2 mL)
    Negative control
  • Unknown organic samples (2 mL each)
    3–4 samples
  • Cork or holder for copper wire (1)

Оборудование

Bunsen burner Watch glasses (6) Forceps

Процедура

1

Heat the copper wire loop in the oxidizing zone of the Bunsen burner until it glows red and no green color is visible (this burns off contaminants and forms CuO).

3 мин Wire is extremely hot
2

Allow the wire to cool slightly, then dip it into the chloroform (positive control). Return the wire to the flame.

3 мин Chloroform is volatile — use fume hood
3

Observe the bright green flame (positive result for halogen). Record the color and intensity.

2 мин
4

Clean the wire by heating until green color disappears. Repeat the test with ethanol (negative control). No green color should appear.

3 мин
5

Test each unknown sample using the same procedure. Record whether each gives a positive (green) or negative result.

10 мин Clean wire between samples
6

Record all results and identify which unknowns likely contain halogen atoms.

4 мин

Ожидаемые результаты

Chloroform produces a vivid green flame (positive). Ethanol produces no green color (negative). Halogen-containing unknowns show green coloration of varying intensity.

Уборка

Allow copper wire to cool. Store organic waste in halogenated or non-halogenated solvent waste containers as appropriate. Wipe down surfaces.

Детали

Категория
Qualitative Analysis
Сложность
Beginner (Middle School)
Продолжительность
25 мин
Прим. стоимость
$5,00
Шаги
6
Материалы
5

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Frequently Asked Questions

What is the objective of Тест Байльштейна на галогены?
Определить, содержит ли органическое соединение атомы галогенов (Cl, Br, I), с помощью теста Байльштейна с медной проволокой.
How difficult is Тест Байльштейна на галогены?
This experiment is rated as Beginner (Middle School). It takes approximately 25 minutes to complete.
What safety precautions are needed for Тест Байльштейна на галогены?
Key safety precautions include: Chloroform is toxic — avoid inhalation and skin contact; Work in a fume hood when testing volatile organics; Hot copper wire can cause burns.
What materials are needed for Тест Байльштейна на галогены?
The main materials required are: Copper wire (20 gauge), Chloroform (CHCl₃), Ethanol (C₂H₅OH), Unknown organic samples, Cork or holder for copper wire.
What results should I expect from Тест Байльштейна на галогены?
Chloroform produces a vivid green flame (positive). Ethanol produces no green color (negative). Halogen-containing unknowns show green coloration of varying intensity.