阅读说明：本技术 一种乙醇的催化氧化实验装置和实验方法 (Catalytic oxidation experimental device and experimental method for ethanol ) 是由 陈燕 王海美 于 2021-08-23 设计创作，主要内容包括：本发明公开了一种乙醇的催化氧化实验装置和实验方法,包括玻璃管、酒精灯和支架,玻璃管的内壁中间处设置有氧化铜薄层,氧化铜薄片的两侧分别放置有第一脱脂棉和第二脱脂棉,第一导气管的另一端通过橡胶软管连接有双联打气球,玻璃管靠近第二脱脂棉的一端设置有第二密封塞,第二密封塞的内部贯穿有第二导气管,第二导气管的外端连接有玻璃弯管,玻璃弯管的外端设置有试管。本发明通过提前制备可重复使用的氧化铜薄层,在课堂演示时,不仅操作更为简单方便,而且实验过程中“黑色氧化铜与红色铜镜反复呈现”的现象非常明显,在教室任何位置的学生都能看到,有利于学生理解乙醇催化氧化为乙醛的反应原理,还能有效激发学生的求知欲和学习兴趣。(The invention discloses a catalytic oxidation experimental device and an experimental method for ethanol, and the device comprises a glass tube, an alcohol lamp and a bracket, wherein a thin copper oxide layer is arranged in the middle of the inner wall of the glass tube, first absorbent cotton and second absorbent cotton are respectively placed on two sides of the thin copper oxide layer, the other end of a first air duct is connected with a duplex balloon through a rubber hose, a second sealing plug is arranged at one end of the glass tube close to the second absorbent cotton, a second air duct penetrates through the inside of the second sealing plug, the outer end of the second air duct is connected with a glass bent tube, and a test tube is arranged at the outer end of the glass bent tube. According to the invention, the reusable copper oxide thin layer is prepared in advance, so that the operation is simpler and more convenient during classroom demonstration, the phenomenon of repeated appearance of black copper oxide and a red copper mirror in the experimental process is very obvious, and the copper oxide thin layer can be seen by students in any position of a classroom, so that the copper oxide thin layer is beneficial for the students to understand the reaction principle of catalyzing and oxidizing ethanol into acetaldehyde, and the learning desire and interest of the students can be effectively stimulated.)

1. The catalytic oxidation experimental device for the ethanol comprises a glass tube (1), an alcohol lamp (2) and a support (14), wherein the support (14) is arranged on two sides of the bottom end of the glass tube (1), the alcohol lamp (2) is arranged in the middle of the bottom of the glass tube (1), the catalytic oxidation experimental device is characterized in that a copper oxide thin layer (3) is arranged in the middle of the inner wall of the glass tube (1), first absorbent cotton (4) and second absorbent cotton (5) are respectively placed on two sides of the copper oxide thin layer (3), a first sealing plug (6) is arranged at one end, close to the first absorbent cotton (4), of the glass tube (1), a first air duct (7) penetrates through the inside of the first sealing plug (6), one end, facing the copper oxide thin layer (3), of the first air duct (7) is connected with an air inlet pipe (8), and the other end of the first air duct (7) is connected with a duplex balloon (9) through a rubber hose, one end of the glass tube (1) close to the second absorbent cotton (5) is provided with a second sealing plug (10), a second air duct (11) penetrates through the inside of the second sealing plug (7), the outer end of the second air duct (11) is connected with a glass bent tube (12), and the outer end of the glass bent tube (12) is provided with a test tube (13).

2. The experimental device for the catalytic oxidation of ethanol as claimed in claim 1, wherein the first absorbent cotton (4) is soaked with ethanol, and the second absorbent cotton (5) is soaked with anhydrous copper sulfate.

3. An ethanol catalytic oxidation experimental device according to claim 1, characterized in that, the outlet port of the inlet pipe (8) is located at one side of the copper oxide thin layer (3), and the burning point of the alcohol burner (2) is located at the bottom of the copper oxide thin layer (3).

4. The catalytic oxidation experimental method of the ethanol is characterized by comprising the following specific steps:

a: preparing a copper oxide thin layer; horizontally placing a hard glass tube, and adding about half spoon of Cu (NO)₃)_2.3H₂0 crystal, a proper amount of 10 percent NaOH solution is contained in a beaker, the hard glass tube is uniformly preheated by an alcohol lamp, and then Cu (NO) is intensively heated₃)_2.3H₂0 crystal to melt, lightly rotating the hard glass tube to make the melted copper nitrate cover the inner wall of the glass tube uniformly, continuing to heat, decomposing the copper nitrate to form a black copper oxide thin layer, and generating NO simultaneously₂、O₂And water vapor, stopping heating after the copper nitrate is completely decomposed, slowly introducing air into the hard glass tube by using a duplex balloon, exhausting gas generated by the reaction, and absorbing the gas by using NaOH solution, thus finishing the preparation of the copper oxide thin layer;

b: preparing Ag₂0 and Ag (NH)₃)₂Mixed suspension of OH; dropwise adding 2% diluted ammonia water into 2% silver nitrate solution till the generated precipitate is completely dissolved to obtain silver ammonia solution, and dropwise adding 10% NaOH solution into the silver ammonia solution till black suspension is generated to obtain Ag₂0 and Ag (NH)₃)₂Mixed suspension of OH;

c: assembling an instrument; limiting the glass tube by a bracket, respectively placing absorbent cotton stained with ethanol and absorbent cotton stained with anhydrous copper sulfate at two ends of a hard glass tube, and respectively connecting two ends of the glass tube with a duplex balloon and a test tube filled with mixed turbid liquid;

d: carrying out experimental operation; after the hard glass tube is uniformly preheated by the alcohol lamp, the thin copper oxide layer is heated in a centralized manner, the black copper oxide gradually turns red under the action of ethanol vapor, a mauve copper mirror is formed after a moment, and the anhydrous copper sulfate on the absorbent cotton ball gradually turns blue, which indicates that water is generated in the reaction and forms blue CuSO after being absorbed by the anhydrous copper sulfate_4.5H₂O, slowly blowing oxygen into the hard glass tube by using a duplex inflating balloon, and changing the copper mirror into blackAnd when the oxygen stops being blown, the copper mirror slowly appears, the operation is repeated, the black copper oxide thin layer and the red copper mirror appear alternately, and the phenomenon shows that the ethanol has catalytic oxidation reaction and holds the Ag₂0 and Ag (NH)₃)₂The formation of acetaldehyde was indicated by the appearance of a bright silver mirror in the test tube in which the OH mixture was suspended.

Technical Field

The invention relates to a catalytic reaction device, in particular to a catalytic oxidation experimental device and an experimental method for ethanol.

Background

The experiment that ethanol reacts with oxygen to generate acetaldehyde under the catalysis of copper is a traditional experiment for learning important properties of ethanol. The current catalytic oxidation experimental method comprises the following steps: 2mL of ethanol is added into a test tube, bright fine copper wires are wound into a spiral shape, the spiral shape is heated and burned on the outer flame of an alcohol lamp, when a layer of black copper oxide is generated on the surface, the spiral shape is inserted into the bottom of the test tube containing the ethanol while the spiral shape is hot, and the black copper oxide can be seen to be reduced into bright red copper. This was repeated several times and the irritating odor of acetaldehyde was smelled at the test tube mouth, indicating that acetaldehyde was formed by the oxidation of ethanol.

The existing experimental methods have the problem of tail gas pollution, the experimental phenomenon is not obvious, the generated acetaldehyde cannot be detected, the activity of the catalyst is not strong, the phenomenon of copper oxide discoloration is not obvious, and the experimental conclusion is not strict.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an experimental device and an experimental method for catalytic oxidation of ethanol.

In order to solve the above technical problem, the present invention provides a first technical solution as follows:

the invention relates to a catalytic oxidation experimental device for ethanol, which comprises a glass tube, an alcohol lamp and a bracket, wherein the bracket is arranged on two sides of the bottom end of the glass tube, the alcohol lamp is arranged in the middle of the bottom of the glass tube, a copper oxide thin layer is arranged in the middle of the inner wall of the glass tube, first absorbent cotton and second absorbent cotton are respectively placed on two sides of the copper oxide thin layer, a first sealing plug is arranged at one end of the glass tube close to the first absorbent cotton, a first air duct penetrates through the first sealing plug, one end of the first air duct, which faces the copper oxide thin layer, is connected with an air inlet pipe, the other end of the first air duct is connected with a duplex inflating balloon through a rubber hose, a second air duct is arranged at one end of the glass tube close to the second absorbent cotton, a second air duct penetrates through the second sealing plug, and the outer end of the second air duct is connected with a glass bent pipe, the outer end of the glass elbow is provided with a test tube.

As a preferable technical scheme of the present invention, the first absorbent cotton is stained with ethanol, and the second absorbent cotton is stained with anhydrous copper sulfate.

As a preferable technical scheme of the invention, the air outlet port of the air inlet pipe is positioned on one side of the copper oxide thin layer, and the combustion point of the alcohol burner is positioned at the bottom of the copper oxide thin layer.

The invention provides a second technical scheme as follows:

the invention also provides a catalytic oxidation experimental method of ethanol, which comprises the following specific steps:

a: preparing a copper oxide thin layer; horizontally placing a hard glass tube, and adding about half spoon of Cu (NO)₃)_2.3H₂0 crystal, a proper amount of 10 percent NaOH solution is contained in a beaker, the hard glass tube is uniformly preheated by an alcohol lamp, and then Cu (NO) is intensively heated₃)_2.3H₂0 crystal to melt, lightly rotating the hard glass tube to make the melted copper nitrate cover the inner wall of the glass tube uniformly, continuing to heat, decomposing the copper nitrate to form a black copper oxide thin layer, and generating NO simultaneously₂、O₂And water vapor, stopping heating after the copper nitrate is completely decomposed, slowly introducing air into the hard glass tube by using a duplex balloon, exhausting gas generated by the reaction, and absorbing the gas by using NaOH solution, thus finishing the preparation of the copper oxide thin layer;

b: preparing Ag₂0 and Ag (NH)₃)₂Mixed suspension of OH; dropwise adding 2% diluted ammonia water into 2% silver nitrate solution till the generated precipitate is completely dissolved to obtain silver ammonia solution, and dropwise adding 10% NaOH solution into the silver ammonia solution till black suspension is generated to obtain Ag₂0 and Ag (NH)₃)₂Mixed suspension of OH;

c: assembling an instrument; limiting the glass tube by a bracket, respectively placing absorbent cotton stained with ethanol and absorbent cotton stained with anhydrous copper sulfate at two ends of a hard glass tube, and respectively connecting two ends of the glass tube with a duplex balloon and a test tube filled with mixed turbid liquid;

d: carrying out experimental operation; after the hard glass tube is uniformly preheated by the alcohol lamp, the thin copper oxide layer is heated in a centralized manner, the black copper oxide gradually turns red under the action of ethanol vapor, a mauve copper mirror is formed after a moment, and the anhydrous copper sulfate on the absorbent cotton ball gradually turns blue, which indicates that water is generated in the reaction and forms blue CuSO after being absorbed by the anhydrous copper sulfate_4.5H₂O, slowly blowing oxygen into the hard glass tube by using a duplex inflating balloon, changing the copper mirror into black, stopping blowing the oxygen, slowly appearing the copper mirror, and repeatedly operating in such a way to realize the black copper oxide thin layer andthe alternate appearance of red copper mirrors indicates that the ethanol has catalytic oxidation reaction and holds Ag₂0 and Ag (NH)₃)₂The formation of acetaldehyde was indicated by the appearance of a bright silver mirror in the test tube in which the OH mixture was suspended.

Compared with the prior art, the invention has the following beneficial effects:

1. the existing state of reactants is reasonably changed, so that the reaction phenomenon is more obvious; by preparing the reusable copper oxide thin layer in advance, the operation is simpler and more convenient during classroom demonstration, and the phenomenon of repeated appearance of black copper oxide and a red copper mirror in the experimental process is very obvious, so that students in any position of a classroom can see the phenomenon, the theory of the reaction of catalyzing and oxidizing ethanol into acetaldehyde can be easily understood by the students, and the learning desire and interest of the students can be effectively stimulated; and meanwhile, ethanol vapor is adopted, so that the dosage of a reagent is small, resources can be saved, the reaction time is short, the reaction is convenient and rapid, acetaldehyde is finally oxidized into acetic acid without discharging air, and the experiment is pollution-free and environment-friendly.

2. A product inspection method is scientifically selected, so that an experimental conclusion is accurate and reliable; the anhydrous copper sulfate on the absorbent cotton ball gradually turns blue, which indicates that water is generated in the reaction, and better helps students to understand that the reaction of catalytic oxidation of ethanol to acetaldehyde is essentially a dehydrogenation reaction, namely, dehydroxylation and hydrogen on carbon on which the hydroxyl is positioned are removed, and Ag is used₂0 and Ag (NH)₃)₂Acetaldehyde is detected by the OH mixed turbid liquid without water bath heating, so that the operation is convenient and rapid, the reaction rate is high, the experimental phenomenon is obvious, and the silver mirror is uniform and attractive. On one hand, students really experience that a new organic substance, namely acetaldehyde is generated, and compared with ethanol, the acetaldehyde has stronger reducibility; on the other hand, the students are made to confirm that ethanol can be oxidized into acetaldehyde by oxygen under the condition of taking copper as a catalyst.

3. Poisons in the experiment are properly treated, and the greening chemical concept is effectively practiced; in the preparation of copper oxide thin layer, double-connected air-inflating ball is used to exhaust NO produced by decomposition of copper nitrate crystal in hard glass tube₂Gas is absorbed by NaOH solution, environmental pollution is prevented, safety and environmental awareness of students are effectively cultivated,accords with the green chemical concept.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.

Wherein like reference numerals refer to like parts throughout.

In addition, if a detailed description of the known art is not necessary to show the features of the present invention, it is omitted. It should be noted that the terms "front," "back," "left," "right," "upper" and "lower" used in the following description refer to directions in the drawings, and the terms "inner" and "outer" refer to directions toward and away from, respectively, the geometric center of a particular component.

In the drawings:

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic diagram of the preparation of copper oxide flakes according to the present invention;

in the figure: 1. a glass tube; 2. an alcohol lamp; 3. copper oxide flakes; 4. first absorbent cotton; 5. second absorbent cotton; 6. a first sealing plug; 7. a first air duct; 8. an air inlet pipe; 9. double balloon-making; 10. a second sealing plug; 11. a second air duct; 12. bending the glass tube; 13. a test tube; 14. and (4) a bracket.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

Example 1

As shown in the figures 1-2, the invention provides a catalytic oxidation experimental device for ethanol, which comprises a glass tube 1, an alcohol lamp 2 and a bracket 14, wherein the bracket 14 is arranged on both sides of the bottom end of the glass tube 1, the alcohol lamp 2 is arranged in the middle of the bottom of the glass tube 1, a copper oxide thin layer 3 is arranged in the middle of the inner wall of the glass tube 1, first absorbent cotton 4 and second absorbent cotton 5 are respectively arranged on both sides of the copper oxide thin layer 3, a first sealing plug 6 is arranged at one end of the glass tube 1 close to the first absorbent cotton 4, a first air duct 7 penetrates through the inside of the first sealing plug 6, an air inlet pipe 8 is connected to one end of the first air duct 7 facing the copper oxide thin layer 3, a duplex inflating ball 9 is connected to the other end of the first air duct 7 through a rubber hose, a second sealing plug 10 is arranged at one end of the glass tube 1 close to the second absorbent cotton 5, a second air duct 11 penetrates through the inside of the second sealing plug 7, the outer end of the second air duct 11 is connected with a glass bend 12, and the outer end of the glass bend 12 is provided with a test tube 13.

Further, the first absorbent cotton 4 is dipped with ethanol, and the second absorbent cotton 5 is dipped with anhydrous copper sulfate.

The air outlet port of the air inlet pipe 8 is positioned at one side of the copper oxide thin layer 3, and the combustion point of the alcohol lamp 2 is positioned at the bottom of the copper oxide thin layer 3.

The invention provides a catalytic oxidation experimental method of ethanol, which comprises the following specific steps:

a: preparing a copper oxide thin layer; horizontally placing a hard glass tube, and adding about half spoon of Cu (NO)₃)_2.3H₂0 crystal, a proper amount of 10 percent NaOH solution is contained in a beaker, the hard glass tube is uniformly preheated by an alcohol lamp, and then Cu (NO) is intensively heated₃)_2.3H₂0 crystal to melt, lightly rotating the hard glass tube to make the melted copper nitrate cover the inner wall of the glass tube uniformly, continuing to heat, decomposing the copper nitrate to form a black copper oxide thin layer, and generating NO simultaneously₂、O₂And water vapor, stopping heating after the copper nitrate is completely decomposed, slowly introducing air into the hard glass tube by using a duplex balloon, exhausting gas generated by the reaction, and absorbing the gas by using NaOH solution, thus finishing the preparation of the copper oxide thin layer;

b: preparing Ag₂0 and Ag (NH)₃)₂Mixed suspension of OH; dropwise adding 2% diluted ammonia water into 2% silver nitrate solution till the generated precipitate is completely dissolved to obtain silver ammonia solution, and dropwise adding 10% NaOH solution into the silver ammonia solution till black suspension is generated to obtain Ag₂0 and Ag (NH)₃)₂Mixed suspension of OH;

c: assembling an instrument; limiting the glass tube by a bracket, respectively placing absorbent cotton stained with ethanol and absorbent cotton stained with anhydrous copper sulfate at two ends of a hard glass tube, and respectively connecting two ends of the glass tube with a duplex balloon and a test tube filled with mixed turbid liquid;

d: carrying out experimental operation; after the hard glass tube is uniformly preheated by the alcohol lamp, the thin copper oxide layer is heated in a centralized manner, the black copper oxide gradually turns red under the action of ethanol vapor, a mauve copper mirror is formed after a moment, and the anhydrous copper sulfate on the absorbent cotton ball gradually turns blue, which indicates that water is generated in the reaction and forms blue CuSO after being absorbed by the anhydrous copper sulfate_4.5H₂And O, slowly blowing oxygen into the hard glass tube by using a duplex inflating balloon, enabling the copper mirror to become black, stopping blowing the oxygen, slowly enabling the copper mirror to appear again, repeatedly operating in such a way, and realizing the alternate appearance of a black copper oxide thin layer and a red copper mirror, wherein the phenomenon indicates that the ethanol has a catalytic oxidation reaction and holds Ag₂0 and Ag (NH)₃)₂The appearance of a shiny silver mirror in the test tube of the OH mixed suspension indicates the formation of acetaldehyde

Specifically, the copper oxide thin layer is prepared in the experiment, under the heating condition, ethanol steam reacts with the copper oxide thin layer to generate a copper mirror, and air is introduced to the copper mirror, so that the copper mirror is immediately changed into the copper oxide thin layer. The repeated operation can realize the alternate appearance of the black copper oxide thin layer and the red copper mirror, and Ag₂0 and Ag (NH)₃)₂The mixed suspension of OH is used for detecting acetaldehyde which is a catalytic oxidation product of ethanol, so that the experimental effect of the silver mirror reaction is enhanced. The specific principle of this experiment is as follows:

2Cu(NO₃)_2.3H20＝2CuO+4NO₂↑+O₂↑+6H₂0

CH₃CH₂OH+CuO＝＝CH₃CHO+Cu+H₂O

2Cu+O₂＝＝2CuO

CH₃CHO+2Ag(NH₃)₂OH+2Ag↓+CH₃COONH₄+3NH₃+H20

CH,CHO+Ag₂O＝＝2Ag+CH₃COOH。

finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that various changes, modifications and substitutions can be made without departing from the spirit and scope of the invention as defined by the appended claims. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.