The method of extracting oxygen, the method of producing oxygen

Let's talk about the industrial method of producing oxygen:

Liquid air fractionation is widely used in large-scale production of oxygen in industry.

First, the air is passed through the filter to remove solid impurities such as dust, and then compressed by the compressor, and then through the molecular sieve purifier to remove impurities such as water vapor and carbon dioxide. Here, molecular sieves can pass through smaller molecules such as nitrogen and oxygen, and play a role in screening molecules. Then it is cooled and depressurized, and when the temperature drops to about -170, the air begins to partially liquefy into the distillation column, and the fractionation is carried out according to the different boiling points of each gas in the air.

The boiling point of liquid oxygen is higher than that of liquid nitrogen, and the two are more easily vaporized than liquid nitrogen. After multi-step fractionation, more than 99 pure oxygen can be obtained, and nitrogen and raw materials for extracting rare gases can be obtained at the same time.

This method is complex. If you need to use oxygen with low purity, you can use molecular sieve adsorption method to separate the air to obtain oxygen. The adsorption capacity of specific molecular sieve for nitrogen is greater than that of oxygen, when the air passes through the molecular sieve bed, the oxygen content of the gas flowing out is higher, and the gas containing oxygen 70 80 can be obtained after multiple adsorption.

This method is operated at room temperature, has a short cycle time, and is easy to automate.

In addition, if high-purity oxygen is required, it can be produced by electrolysis of water, which is expensive and only suitable for small-scale production.

Oxygen separated from the air is typically stored under pressure in sky-blue cylinders for industrial, medical or other use.

Industrially, the air is pressurized and the temperature is lowered to about minus 190 degrees, and then the liquid that separates is oxygen, and the gas is nitrogen. If it is a laboratory, it can be prepared by heating potassium permanganate, adding hydrogen peroxide to monoxide (catalyst), or heating potassium chlorate, etc.

It depends on whether it is extracted industrially or in the laboratory, the electrolysis of water in the industry, and the extraction of potassium permanganate in the laboratory.

Hydrogen peroxide is heated and decomposed or a little manganese dioxide is added as a catalyst, do not heat.

Potassium permanganate is prepared by heating.

Potassium chlorate is heated or added to manganese dioxide.

There is also photosynthesis from plants.

Laboratory: Heating a mixture of potassium chloride and manganese dioxide.

2kClO3 = (heating, mNO2) 2kCl + 3O2 and oxygen is produced by electrolysis of water.

2h2o = (energized) 2h2 + o2

Heating peroxide, e.g.: 2Na2O2-->2Na2O+O2 Industry: The drainage method is suitable for gases that are insoluble in water, and the upward exhaust method is suitable for gases that are heavier than air (that is, gases with a relative molecular mass greater than 29, oxygen 32 can, the jar is being placed, and the catheter extends into the bottom of the bottle, because the collected gas is heavier than the air, the air is squeezed out), and the downward exhaust method is suitable for gases that are lighter than air, such as hydrogen and ammonia, and the jar is inverted and the catheter is extended into the bottom of the bottle

Oxygen can be collected using the upward exhaust method and the drainage method.

Hydrogen peroxide heating can produce oxygen, but it is generally not used in the laboratory because a large amount of water vapor will be generated, and the laboratory produces oxygen by heating potassium permanganate to produce potassium manganate manganese chloride and oxygen, because no impurity gas is produced The laboratory can also heat potassium chlorate and manganese dioxide (manganese dioxide as a catalyst) to produce potassium chloride and oxygen

In industry, the air depressurization method is used (80% of the air is nitrogen, 20% is oxygen, and the boiling points of the two are different).

High school textbooks say that there are submarines that use sodium peroxide and carbon dioxide exhaled by humans to produce oxygen.

Laboratory Preparation of Oxygen:

1) Drug: potassium permanganate (purple-black crystal).

3) Experimental setup:

A Precautions: Use the alcohol lamp to determine the height of the test tube.

The iron clamp is clamped in the middle and upper part of the tube for easy heating.

The mouth of the test tube should be slightly inclined downward to prevent the wet water from backing up to the bottom of the tube during the reaction, causing the tube to rupture.

The catheter should not be extended too long into the test tube to facilitate the discharge of oxygen and prevent the drug from clogging the catheter.

When using potassium permanganate for the reaction, a small ball of cotton needs to be placed at the mouth of the test tube to prevent potassium permanganate powder from entering the conductor during heating.

Tube. b Scope of application: This device is suitable for the reaction of solid heating to produce gas.

4) Collection Method:

The drainage method --- because oxygen is poorly soluble in water.

5) Full method: put the wooden strip with sparks on the mouth of the bottle, if it is rekindled, it has been full.

6) Test method: Stick the wooden strip with sparks into the bottle, if it is rekindled, it proves that it is oxygen.

7) Full placement: The gas collection bottle filled with oxygen should be covered with the mouth of the slide and placed upward.

8) Operation steps (mainly seven steps):

Check --- airtightness of the device.

Fill --- with the medicine and plug it tightly with a rubber stopper with a catheter.

The clamping --- fix the test tube on the iron frame with an iron clamp, and make the nozzle slightly inclined downward, and the drug is spread flat at the bottom of the test tube.

Light --- alcohol lamp, heat the test tube, and exhaust the air in the tube.

Oxygen is collected by draining ---.

Take --- catheter out of the sink.

Extinguish --- alcohol lamp.

The drainage method is used to collect gases. Prepare a sink, a bottle. Fill the bottle with water and fill the sink with water.

The bottle is suspended in the water of the sink, and the mouth of the pipe that discharges the gas is placed slightly further inside the mouth of the bottle. After the water in the bottle is drained, the bottle is filled with gas to be collected. (This gas is required to be intolerant of water).

Extracting oxygen from **? Supplementary clarification of the question!

The methods for preparing oxygen are: solid-liquid room temperature type, solid-solid heating type.

1. Solid-liquid type at room temperature, which is prepared by using hydrogen peroxide and manganese dioxide to react at room temperature to produce oxygen.

1) Check: Check the air tightness of the device by using the principle that the air pressure inside and outside the device is equal and the liquid does not fall back.

2) Loading: Remove the rubber stopper, fill the Erlenmeyer flask with manganese dioxide, and then plug the rubber stopper.

3) Fixed: Connect the gas generator and the collection device in the order from bottom to top and from left to right.

4) Note: Inject hydrogen peroxide solution into the Erlenmeyer flask from the long-necked funnel.

5) Collect: Collect oxygen by upward exhaust air method (gas density is greater than air) or drainage method (gas is insoluble in water).

2. Solid-solid heating type, which is prepared by heating potassium chlorate and manganese dioxide (or heating potassium permanganate) to decompose and produce oxygen.

1) Check: Check the air tightness of the device by using the principle of gas heating expansion.

2) Installation: Remove the rubber stopper, fill the test tube with potassium chlorate and manganese dioxide (or potassium permanganate), and then plug the rubber stopper.

3) Fixed: Connect the gas generator and the collection device in the order from bottom to top and from left to right.

4) Point: Light the alcohol lamp, preheat the test tube, and then fix it on the drug site to heat.

5) Collect: Collect oxygen by upward exhaust air method (gas density is greater than air) or drainage method (gas is insoluble in water).

Test Method:

1. Inspection: Use a wooden strip with sparks to stretch into the gas collection cylinder, if the wooden strip is re-ignited, it proves that it is O2.

2. Full: Put a wooden strip with sparks on the mouth of the gas collection cylinder, if the wooden strip is re-ignited, it proves that O2 is full.

The 6 methods of producing oxygen are as follows:

1. Electrolyzed water: 2H2O = energized = 2H2 + O2; Water decomposes hydrogen and oxygen when electrified.

2. Air separation.

3. Heating potassium permanganate: decomposition products potassium manganate, manganese dioxide and oxygen.

4. Decompose hydrogen peroxide.

5. Heat the mixture of potassium chlorate and manganese dioxide.

6. Decompose hydrogen peroxide.

Physical properties of oxygen:

1. Color, taste and state: Normally, it is a colorless and odorless gas.

2. Density: Under standard conditions, the density is slightly greater than that of air. The upward emptying method can be used.

3. Solubility: oxygen is not easily soluble in water. It can be collected using the drainage method.

4. Three-state change: After cooling, oxygen can change into a light blue liquid, or even a light blue snowflake-like solid.

Method 1: Oxygen is produced with potassium permanganate, steps: checking-installing-setting-pointing-receiving-leaving-extinguishing.

Check --- check the airtightness of the device.

Fill --- medicines.

Fix the test tube to the iron frame ---.

Light --- alcohol lamp to heat (preheat first, note: always let the test tube be evenly heated first, otherwise the test tube will burst due to uneven heat and cold).

Collect --- collect gas (you can use the drainage method, the upward exhaust method).

Remove the catheter from the sink --- (this step is not necessary if using the upward air exhaust method, but it is best to remove the catheter and place the slide on the lid first).

Turn off --- alcohol lamp.

Method 2: Hydrogen peroxide (hydrogen peroxide) to produce oxygen, steps: check --- --- receive.

Check the --- and check the airtightness of the device: clamp the catheter with a clamp (two catheters should be used, and the middle should be connected with a shorter rubber tube for easy inspection), and then add water to the long-necked funnel, if the water column in the neck of the long-necked funnel does not fall, it means that the airtightness is good.

Fill --- medicines, first solids, then liquids (to prevent liquid splashing).

Collect --- gas (same as potassium permanganate collection method).

The production of oxygen in the laboratory is made of impulse oxygenated compounds as raw materials, and these oxygenated compounds must meet the following two conditions: First, this kind of oxygenated compounds are relatively unstable, and they are easy to decompose when heated and release oxygen. Second, the amount of oxygen in this oxygenated compound is relatively high, which can separate and release more oxygen.

Potassium chlorate is mostly used in the laboratory to heat to produce oxygen to produce potassium chloride and oxygen. Manganese dioxide is used as a catalyst.

The device is characterized by the heating and decomposition of the solid to produce gas, which prevents the wet water in the solid from being heated into water vapor and condensing and refluxing at the test tube mouth, resulting in the rupture of the test tube bottom, and the test tube mouth should be slightly inclined downward.

The oxygen collection method can be used to collect oxygen, and the exhaust air method is generally not used, because the oxygen density is close to the air, and it is not easy to drain the air, resulting in impure oxygen collected.

At the end of the experiment, it is necessary to take out the air duct from the sink first, and extinguish the alcohol lamp to prevent the air pressure in the device from decreasing due to the cessation of heating, causing water to suck into the device and damage the device.

In addition, hydrogen peroxide can also be used to decompose at room temperature under the catalysis of manganese dioxide to generate oxygen, this device does not heat, it belongs to the liquid loose skin skin at room temperature and the solid contact to generate gas, the solid is placed in a jar, the liquid is gradually added through the separating funnel, and the two contact to produce oxygen.

How oxygen is produced is as follows:

The equation for laboratory-made oxygen: 2h202=mn02=2h20+02. 2kmn04=a=k2mn04+ mn02+ 02 Note:

Because the reaction produces Mn02, there is no need to add Mn02 as a catalyst). 2kc103=a=2kc1+302 ↑。

Physical properties of oxygen: colorless and odorless gas, melting point, boiling point, relative density (-183c, water=1), relative vapor density air=1), saturated vapor pressure (-164c), critical temperature, critical pressure, octanol water partition coefficient: .

Atmospheric volume fraction: about 21%). Allotropes:

Ozone (03), tetrameric oxygen (04), red oxygen (08).

Chemical properties: The chemical properties of oxygen are relatively reactive. With the exception of rare gases and less reactive metal elements such as gold, platinum, and silver, most of the elements can react with oxygen, and these reactions are called oxidation reactions, and the compounds produced by the reactions (composed of two elements, one of which is oxygen) are called oxides.

In general, aqueous solutions of non-metallic oxides are acidic, while alkali metals or alkaline earth metal oxides are alkaline.

In addition, almost all organic compounds can be violently burned in oxygen to form carbon dioxide and water. In chemistry, the chemical reaction between a substance and oxygen was defined as an oxidation reaction, and a redox reaction refers to a reaction in which electrons are transferred or shifted. Oxygen is flammable, oxidizing.