JPS60187336A - Absorbent for carbon monoxide - Google Patents

Abstract

PURPOSE:To prepare a solid CO absorbent having high selective absorption characteristic for CO and very high resistance to deterioration due to water and other poisoning gas by prepg. a compsn. consisting of CuCl, AlCl3, aromatic compd., and acidic oxide. CONSTITUTION:CuCl, AlCl3, and an arom. compd. (e.g. toluene) are mixed with an acidic oxide (e.g. Al2O3). The proportion of each component is 1-50pts.wt. the first and the second component per 100pts.wt. Al2O3, and the amt. of the first component is made slightly larger than the amt. of the second component. Furhter, the amt. of the arom. compd. is regulated to be 0.1-0.5mol basing on the amt. of the first component. The absorbent has resistance to water and to deterioration due to O2, H2S, CO2, NO, SO2, etc. Accordingly, it is highly effective for separation by absorption of CO from gaseous mixture contg. large amt. of H2O and O2 together with CO, such as waste gas from coke oven. Moreover, elimination and regeneration of the absorbent are easy, so the absorbent is industrially highly valuable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an absorbent for -carbon oxide (hereinafter referred to as CO), particularly from a mixed gas containing CO.

This invention relates to a solid absorbent that selectively absorbs CO and is less susceptible to water deterioration.

CO is a basic raw material in synthetic chemistry, and research is underway in various fields on the effective use of CO contained in coke oven exhaust gas. As for an absorbent for separating and concentrating CO, a copper aluminum tetrachloride (CuA10/4) t/'ene solution (0O8ORB solution) is well known. When this solution is used, there are drawbacks such as significant deterioration due to water despite its high absorption capacity and toluene as a solvent being mixed in during CO recovery.

The present invention makes full use of the advantages of the 0O8ORB solution,
In addition, the present invention proposes a solid CO absorption/separation agent that eliminates the above-mentioned drawbacks, has a highly selective absorption and separation performance for CO, and is extremely resistant to deterioration due to water and other poisonous gases.

That is, the present invention relates to a water-resistant carbon oxide absorbent containing cuprous chloride, aluminum chloride, an aromatic compound, and an acidic oxide.

The absorbent of the present invention not only has extremely high water resistance compared to the C080RB solution, but also has the property of being activated by water. Although the reasons for these are not clear, in the present invention, the three components consisting of cuprous chloride, aluminum chloride, and an aromatic compound form a complex on an acidic oxide and are stabilized, and the aromatic compound in the complex is stabilized on a carrier. This is thought to be due to some kind of interaction with acidic oxides that act as oxidants.

The first component of the present invention is cuprous chloride monovalent copper ion (cu (iD stands for co?r), which is known to be well absorbed.
A CO absorbent consisting of cupric halide and activated carbon has been proposed.

However, in the present invention, if even one of the four constituent components is missing, an absorbent having water resistance cannot be provided. That is, the first component copper chloride, the second component aluminum chloride, the third component aromatic compound, and the fourth component acidic oxide are all essential components for the present invention.

For example, in an absorbent in which cuprous chloride and toluene are supported on alumina, except for aluminum chloride as the second component shown in Experimental Example 2 described later, cu(1) is easily oxidized by trace amounts of oxygen. The absorption capacity decreases due to the formation of Cu (molecular weight). This was revealed in the ESR spectrum of the absorbent. In other words, Cu (I) ions are not detected in the EAR, whereas Cu (Ir) ions are detected. Take advantage of
An absorbent made of cuprous toluene chloride and alumina was measured by ESR before and after aeration of a trace amount of oxygen. The results are shown in FIG. 2, from which it can be seen that in the absorbent lacking the second component aluminum chloride, Cu (U) increases due to oxygen and the absorption capacity decreases.

Therefore, it is clear that aluminum chloride acts to form a complex with cuprous chloride and an aromatic compound to keep copper ions monovalent and stable, and is an essential component.

Further, the aromatic compound as the third component is necessary not only to form a complex with the first component and the second component, but also to provide water resistance, which is a characteristic of the adsorbent of the present invention. Furthermore, this aromatic compound plays an extremely important function in the adsorption and desorption of CO.

(See Experimental Example 1 below) The temperature at which the absorbent deteriorates varies depending on the type of aromatic compound forming the complex. When using toluene, about 12
It is stable up to 0C and can continuously absorb and desorb GO. Generally, 20 to 3 points higher than the boiling point of the aromatic compound used.
It is believed that at temperatures higher than 0C, the aromatic compounds decomplex and are removed and the absorbent deteriorates. Therefore,
The aromatic compound that forms the complex may be appropriately selected depending on the operating conditions for absorbing and desorbing CO.

Generally, general-purpose materials such as benzene, toluene, xylene, and polystyrene are used. However, solvents that do not have the ability to dissolve copper chloride or aluminum chloride are not preferred.

Furthermore, since the absorbent of the present invention usually performs the desorption operation after CO absorption by heating, low boiling point solvents or high volatility solvents are not preferred.

The acidic oxide as the fourth component acts as a carrier that uniformly disperses and immobilizes the complex consisting of cuprous chloride, aluminum chloride, and an aromatic compound.

In this case, the acidic oxide has either a Gronsted acid site, which is stable at low temperatures, or a Lewis acid site, which is easily generated at high temperatures, on its surface, and at the same time the complex is sufficiently dispersed. Desirably, aromatic compounds are capable of maintaining interactions. Examples include alumina, titania, silica, silica-magnesia, and silica-alumina.

Further, if the surface area is too large, the pores become too small and the dispersibility of the complex compound decreases, which is not preferable. Usually, those having a BET surface area of 40 to 400 Il12/g, preferably 50 to 300 m2/9 are used.

Although the structure of the complex is not clear, it is thought that it is formed of cuprous chloride, aluminum chloride, and an aromatic compound in approximately 1 mole each. The amount supported on the acidic oxide is 1 to 50 parts by weight, preferably 10 to 40 parts by weight, as a total of the first and second components, per 100 parts by weight of the acidic oxide.

In this case, if aluminum chloride is present in excess, it will react with water and cause MCI! may occur and cause the absorbent to deteriorate. Therefore, it is preferable to support cuprous chloride in a slight excess.

Furthermore, the aromatic compound is generally supported in an amount of 0.1 to 0.5 mol relative to the first component (or second component). In particular, the supported amount is preferably 0.25 mol or more.

As mentioned above, the absorbent of the present invention has water resistance and is less likely to be degraded by oxygen H8, Go No, 802, etc. 2 2 , so it contains a large amount of moisture, oxygen, etc. together with CO from coke oven exhaust gas etc. It is extremely effective in absorbing and separating CO from mixed gas. Furthermore, it can be easily desorbed and regenerated and has high industrial value.

Example 1 For copper chloride, a commercially available special grade reagent (manufactured by Wako Tsumugi Pharmaceutical Industries) was used, and for aluminum chloride, a PCB quantitative reagent (manufactured by Wako Tsumugi Pharmaceutical Industries) was used.
was used as is. Copper chloride 0-6 & (6 m-vnol) above in a Ronas flask to 200 m under drying conditions
and 0.81 (6B-rnol) of aluminum chloride were added and dissolved by adding 20rnlf of toluene as an aromatic compound, and the mixture was heated and kept at 60C for 2 hours. The solution is CuC7
-Aj'O1!5- It exhibited a transparent black color characteristic of toluene complex solutions. For the above 9 elements, commercially available nitrogen (here, 99,999% purity manufactured by Teikoku Sanso Co., Ltd.) was filled with commercially available molecular sieve 3A (here, manufactured by Nikka Seiko Co., Ltd.) immediately before use. The product was purified by passing it through a column.

Alumina A carrier calcined at 550C for 3 hours as an acidic oxide (average pore diameter 108A manufactured by Catalysts Kasei Co., Ltd.)
BET surface area 230 m2/l') 10J1.2
After the inside of the flask was sufficiently degassed using a vacuum pump, the solution prepared earlier was added thereto using a dropping funnel. Thereafter, the inside of the eggplant flask was reduced in pressure (6w Hg) and evacuated day and night to sufficiently remove toluene and obtain an absorbent.

Analysis of carbon in this absorbent revealed that C=1.4wt
%, and the solvent toluene was removed, but the toluene forming the complex remained, and the toluene and Ou were 0.25%.
: was found to exist in a molar ratio of 1.

A mixed gas of J ATM GO and N2 (co
When we checked the absorption performance of CO by aerating the partial pressure (0.79 atm), we found that it was 1.5 m-mol in 10 minutes! C of
Absorbed O. The absorbent was then heated to 9 oc at 1 atm to desorb Co. At this time, CO is 1.3 m -m
ol was released. After cooling the absorbent, about 16 m-rnol of N2° was passed through the absorbent using nitrogen as a carrier gas, and then the above-mentioned mixed gas was passed through the absorbent, resulting in 3.5 m-mol in 10 minutes! Absorbed OCO. From then on H2
When zero aeration and mixed gas aeration were repeated, the CO absorption amount reached equilibrium at about 56 m -mat.

In addition, this equilibrium absorbent contains a nitrogen-oxygen mixed gas (0.02 partial pressure 0.05 atm) and a 9-H2S mixed gas (H2S).
2S partial pressure 0,003 atm), CO2 gas (CO21
Atm), N2-8o2-No mixed gas (S02 partial pressure 0.005 atm, No partial pressure 0.003 atm), etc. were passed through, and no change was observed in the amount of CO absorbed.

Examples 2 to 6 The same operation as in Example 1 was performed except that the carrier shown in Table 1 was used instead of the alumina A carrier fired at 550C in Example 1. The amount of acidic oxide used was the same as in Example 1. -The absorption amount of carbon oxide is also shown in Table 5 below.

Table 1 Examples 7 to 8 The same operations as in Example 1 were performed except that the solvents in Table 2 were used instead of toluene in Example 1. The amount of solvent used was the same as in Example 1. The results are also shown in Table-5.

Table 2 Example 9 When preparing the absorbent in Example 1, 20 ml of carbon disulfide was used instead of toluene, and polystyrene (molecular weight 800
) An absorbent was obtained in the same manner as in Example 1 except that IJF was added.

Using this absorbent, CO was absorbed and separated from a mixed gas of CO and N2 in the same manner as in Example 1. The desorption temperature was set to 1200, and after cooling, H2016m-rnol was passed through the absorbent to absorb CO gas again. The results of repeated absorption and desorption are shown in Table 3.

In addition, the FT-IR spectrum after using this absorbent shows 2
925cm, 2850cm, 1470cm.

Characteristic absorption bands of -CH2 asymmetric stretching vibration, -0M2 symmetric stretching vibration, -CH2 scissor vibration, and aromatic G-H out-of-plane bending vibration were observed at 740 cm-1, and it was identified as polystyrene. Carbon disulfide was removed when heated to 120C, and 0uCI showed stable absorption capacity as shown in Table 3! This is because the -A10J5-polystyrene complex existed stably on the alumina carrier even after water treatment.

Table-3 Examples 10 to 11 The supported amount of copper chloride and aluminum chloride in Example 1 was 6
m-mo/ to 18 m-m. z, 24m-m0/
The same operation as in Example 1 was performed except that the amount was increased to . The results are also shown in Table-5.

Even if the supported amount is increased, the GO absorption l· does not increase beyond a certain l−.

Table 4 Table 5 Experimental Example 1 An absorbent obtained in the same manner as in Example 1 was subjected to absorption/desorption and N20 aeration until it exhibited an equilibrium absorption capacity for CO. The u FT-E spectrum is shown in FIG. The peaks characteristic of toluene are at 700 cm and 2900 cm.
−' is clearly covered. (Figure 1 a) After heating this absorbent to 15 DC, GO was absorbed in the same way, but after aerating H2OB m -vnol, CO
The adsorption capacity of was significantly decreased.

After heating, the intensity of the toluene peak decreased in the FT (F) spectrum of the absorbent (Fig. 1b). This shows that the presence of toluene, or aromatic compounds, affects water resistance and at the same time that CO It was found that this is an important factor in the continuous action of adsorption and desorption.

The FT-4R spectrum in Figure 1 is of JEOL M, y
This was done using ut-1oo, and the transmittance of KBr was 100, and the transmittance of each material was 3% (absorbent).
is diluted with KBr (97%) ~ Relative transmittance is shown.

Experimental Example 2 Only cuprous chloride was dissolved in toluene, and an absorbent without aluminum chloride was obtained in the same manner as in Example 1. The trace amount oxygen mixed gas used in Example 1 was added to this absorbent at a rate of 5 JJ/
After aeration for 30 minutes at min., a mixed gas of CO and N2 was aerated. GO was hardly absorbed. When comparing the ESR spectra of the absorbent before oxygen aeration and the deteriorated absorbent, it was found that the peak was small before oxygen aeration, but the peak was large in the deteriorated absorbent.

The KSR spectrum shown in FIG. 2 was measured in the range of 2360 to 4560 G (Gauss) using JEOL MFg2xc. The left side of Figure 2 is 2360G.

The one on the right is 4360G. The vertical axis shows the spin radical concentration.

In Figure 2, both a and b are the ESn of unused absorbent.
In the spectrum, a is measured by increasing the sensitivity of b by 2000 times. 0 is measured after oxygen ventilation, and the sensitivity is the same as b. In this case, the sensitivity is proportional to the amount of Cu++ present. Note that Cu+ is not detected. By comparing b and 0, this absorbent has Ou++ after oxygen aeration.
It can be seen that the proportion of

[Brief explanation of drawings]

Figure 1 shows the FT-IR spectrum of the absorbent obtained in Example 1 of the present invention after absorption desorption and aeration of H2O until it exhibits the equilibrium absorption capacity of CO, and the FT-IR spectrum of the absorbent obtained in Example 1 of the present invention at 150C.
The FT-E spectrum is shown when heated to . FIG. 2 shows the R8R spectra of the absorbent of the present invention, excluding aluminum chloride, before and after oxygen aeration. Agents 1) Akira agent Ryo Hagiwara - Sanryu 7

Claims (1)

[Claims] A water-resistant carbon oxide absorbent comprising cuprous chloride, aluminum chloride, an aromatic compound and an acidic oxide.