CN114832583B

CN114832583B - Application of carboxylate in trapping sulfur dioxide

Info

Publication number: CN114832583B
Application number: CN202110135835.8A
Authority: CN
Inventors: 张兆富; 韩布兴
Original assignee: Institute of Chemistry CAS
Current assignee: Institute of Chemistry CAS
Priority date: 2021-02-01
Filing date: 2021-02-01
Publication date: 2023-02-07
Anticipated expiration: 2041-02-01
Also published as: CN114832583A

Abstract

The invention discloses application of carboxylate in trapping sulfur dioxide. The carboxylate of the present invention is used in any of: 1) Capturing sulfur dioxide; 2) Preparing an absorbent for capturing sulfur dioxide; the carboxylate anion is a branched carboxylate radical with a carbon chain with the carbon number more than 6, and the cation is a substituted quaternary ammonium ion and/or a substituted quaternary phosphonium ion. The invention discloses a method for efficiently and energy-saving capturing sulfur dioxide by adopting stable carboxylate to water, which comprises the following steps: and introducing gas containing sulfur dioxide into the carboxylate or the water solution of the carboxylate to enable the gas to absorb the sulfur dioxide, so as to obtain a combination of the carboxylate and the sulfur dioxide separated out from the water, and realize the capture of the sulfur dioxide by the carboxylate. The carboxylate can obtain higher sulfur dioxide trapping capacity at high temperature and low sulfur dioxide partial pressure, and the combination of the carboxylate and the sulfur dioxide is stable to water; the absorption speed of the sulfur dioxide is high.

Description

Use of carboxylates for capturing sulfur dioxide

Technical Field

The invention relates to application of carboxylate in trapping sulfur dioxide, and belongs to the field of gas separation.

Background

With the development of social economy, the consumption of fuel is also increasing, and a large amount of sulfur dioxide is generated. In recent years, people have higher and higher environmental concerns, and the limits of the laws and regulations on the emission of sulfur dioxide are more and more strict. Currently, in industry, desulfurization of flue gas mainly utilizes limestone, quicklime and slaked lime to absorb sulfur dioxide, and besides consuming a large amount of limestone, a large amount of solid waste is generated at the same time. On the other hand, sulfur dioxide can be used as a raw material for producing sulfuric acid or sulfur. The reversible absorption of sulfur dioxide has attracted a great deal of scientific attention.

Since the first time that the chemical institute of chinese academy chemistry utilized guanidine lactate ionic liquids for the chemisorption of sulfur dioxide (angelw. Chem. Int. Ed.2004, 2415), a number of researchers have conducted studies in this regard (ind. Eng. Chem. Res.2019,58, 13804). The wuweize et al studies showed that the strength of the acid corresponding to the anion affects the absorption of sulfur dioxide by ionic liquids (j. Phys. Chem.b 2013,117, 2482). However, the ionic liquid has high viscosity and takes a long time to absorb sulfur dioxide, which is not suitable for large-scale application.

Various investigators have investigated the absorption of sulfur dioxide by aqueous solutions of various ionic liquids, low temperature molten salts (j.of Hazardous Materials 2011,194,48, chemical Engineering Journal 2013,215-216,36, ind, chem.res.2014,53,15207, energy Fuels 2017,31,4193, energy Fuels 2019,33,8937, ind, chem.res.2020,59, 16786. The result shows that the viscosity of the aqueous solution is low, the speed of absorbing sulfur dioxide is high, and the absorption balance can be achieved in a short time. Since the removal of sulfur dioxide from the water absorbent needs to be carried out at a relatively high temperature, continuous evaporation of water during the removal of sulfur dioxide requires the consumption of a large amount of heat energy, and the practicability thereof needs to be improved. The field that the aqueous solution is used as an absorbent and simultaneously keeps low energy consumption in the absorption and desorption processes is blank.

Disclosure of Invention

The invention aims to provide application of carboxylate in trapping sulfur dioxide. The invention has the advantages of high trapping amount, high trapping efficiency, water stability and temperature universality, and has good application prospect.

The carboxylate provided by the invention can be applied to any one of the following applications:

1) Capturing sulfur dioxide;

2) Preparing an absorbent for capturing sulfur dioxide;

the carboxylate anion in the carboxylate is carboxylate radical with carbon chain with carbon atom number greater than 6, and the cation is substituted quaternary ammonium ion and/or substituted quaternary phosphonium ion.

In the application, the carboxylate with the carbon chain with the carbon number more than 6 is at least one of 2, 2-dimethyl hexanoate, 2-ethyl heptanoate, 2-propyl pentanoate and 2-propyl hexanoate.

In the present invention, the substituent group contained in the carbon chain in the carboxylate group having a carbon chain with a carbon number of more than 6 is a straight chain unless otherwise specified.

In the above application, the structural formulas of the substituted quaternary ammonium ion and the substituted quaternary phosphonium ion are respectively shown as the following formulas I and II:

in the formulas I and II, n is an integer of 4-16, and the stituents in the formulas I and II are the same or different.

In the application, in the formula I, n is an integer of 4-6; specifically, the substituted quaternary ammonium ions shown in the formula I are tetra-n-butylammonium and/or tri-n-hexylammonium;

in the formula II, n is an even number of 4-16; specifically, the substituted quaternary phosphonium ion shown in the formula II is at least one of tetra-n-butylphosphine, tri-n-butyl-n-hexylphosphine, tri-n-butyl-n-octylphosphine, tri-n-butyl-n-decylphosphine, tri-n-butyl-n-dodecylphosphine, tri-n-butyl-n-tetradecylphosphine and tri-n-butyl-n-hexadecylphosphine.

The invention also provides an absorbent for trapping sulfur dioxide, which contains the carboxylate.

The invention further provides a method for efficiently and energy-saving capturing sulfur dioxide by adopting carboxylate, which is stable to water and comprises the following steps: and introducing gas containing sulfur dioxide into the carboxylate or the water solution of the carboxylate to enable the gas to absorb the sulfur dioxide, so as to obtain a combination of the carboxylate and the sulfur dioxide separated out from the water, and realize the capture of the sulfur dioxide by the carboxylate.

In the above method, the mass ratio of the carboxylate to water in the carboxylate aqueous solution may be 1;

the conditions for absorbing sulfur dioxide are as follows: the sulfur dioxide partial pressure in the gas containing sulfur dioxide can be 0.0001-0.1 MPa, specifically 0.0001MPa, 0.001MPa, 0.01MPa, 0.1MPa; the temperature can be 25-80 ℃, specifically 25 ℃ and 80 ℃.

In the above method, the amount of absorption of sulfur dioxide per gram of the carboxylate may be 0.028 to 0.205 g, specifically 0.028 g, 0.073 g, 0.094 g, 0.10 g, 0.105 g, 0.107 g, 0.108 g, 0.11 g, 0.112 g, 0.113 g, 0.115 g, 0.118 g, 0.121 g, 0.193 g, 0.81 g, 0.83 g, 0.93 g, 0.97 g, 0.205 g.

The invention has the following advantages:

1. the carboxylate can obtain higher sulfur dioxide trapping capacity at high temperature and low sulfur dioxide partial pressure.

2. When an aqueous solution of the selected carboxylic acid salt absorbs sulfur dioxide, its combination with sulfur dioxide will precipitate out of the water as a liquid, indicating that the combination of the selected carboxylic acid salt and sulfur dioxide is stable to water.

3. The carboxylate or the water solution of the carboxylate has high absorption speed on sulfur dioxide.

Detailed Description

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

The carboxylates in the following examples are synthesized according to the methods in the literature (Suarez, P.A.Z.; dullius, J.E.L.; einloft, S.; DE Souza R.F. and Dupont, J., polyhedron,1996,15, 1217-1219).

The substituents contained in the carbon chain in the reagents used in the examples below are straight chain unless otherwise specified.

Examples 1,

Taking 1 g of tri-n-butyl-n-hexylphosphine 2-ethylhexanoate, adding 1 g of water into a glass bottle, introducing a mixed gas of sulfur dioxide and nitrogen (sulfur dioxide partial pressure of 0.001MPa and nitrogen partial pressure of 0.099 MPa) at the temperature of 25 ℃ at the speed of 20 ml per minute for 12 hours, and continuously stirring to separate the system into an organic phase and a water phase. The amount of absorbed sulfur dioxide was 0.116 grams as determined iodometric analysis.

Under the same conditions, tri-n-butyl-n-hexylphosphine 2-ethylhexanoate is replaced by the following reagents respectively: tetra-n-butylphosphine 2-ethylhexanoate, tri-n-butyl-n-octylphosphine 2-ethylhexanoate, tri-n-butyl-n-decylphosphine 2-ethylhexanoate, tri-n-butyl-n-dodecylphosphine 2-ethylhexanoate, tri-n-tetradecylphosphine 2-ethylhexanoate, tri-n-butyl-n-hexadecylphosphine 2-ethylhexanoate, tetra-n-butylammonium 2-ethylhexanoate, tri-n-butylhexylammonium 2-ethylhexanoate, tri-n-butylhexylphosphine 2-propylvalerate, tri-n-butylhexylphosphine 2, 2-dimethylhexanoate, tri-n-butylhexylphosphine 2-propylhexanoate, tri-n-hexylphosphine 2-ethylheptanoate, and the absorption of sulfur dioxide were measured, and new liquid phases were formed after absorption of sulfur dioxide, respectively, at absorption amounts of 0.110, 0.108, 0.97, 0.93, 0.83, 0.81, 0.113, 0.112, 0.094, 0.97, 0.105, 0.107 g.

Examples 2,

The method is the same as the method in the embodiment 1 of the invention, except that: 0 g, 0.1 g, 0.5 g, 5 g and 10 g of water are respectively added into 1 g of tributyl hexyl phosphine 2-ethyl hexanoate in a glass bottle to obtain the sulfur dioxide absorption amounts of 0.113, 0.115, 0.118 and 0.121 g respectively. The amount of absorption of the above carboxylic acid salts at different water contents compared to the results of example 1 of the present invention shows that the amount of absorption of sulfur dioxide by carboxylic acid salts is stable for water.

Examples 3,

The method is the same as the method in the embodiment 1 of the invention, and the difference is that: the sulfur dioxide trapping temperature was 80 ℃ and the sulfur dioxide absorption by tri-n-butyl-n-hexylphosphine 2-ethylhexanoate was determined to be 0.073 g. This example, which still achieves a higher sulfur dioxide capture capacity at high temperatures compared to example 1 of the present invention, demonstrates that the amount of sulfur dioxide absorbed by the aqueous carboxylate solution of the present invention at different temperatures is not affected by temperature.

Examples 4,

The method is the same as the method in the embodiment 1 of the invention, and the difference is that: the partial pressures of sulfur dioxide in the introduced sulfur dioxide/nitrogen mixed gas are respectively 0.1MPa, 0.01MPa (when the sulfur dioxide is 0.01MPa, the nitrogen partial pressure is 0.09 MPa) and 0.0001MPa (when the sulfur dioxide is 0.0001MPa, the nitrogen partial pressure is 0.0999 MPa), and the absorption amounts of tri-n-butyl n-hexyl phosphine 2-ethyl hexanoate on the sulfur dioxide under the conditions of different partial pressures of the sulfur dioxide are respectively measured to be 0.205 g, 0.193 g and 0.028 g. Illustrating the amount of absorption of the above aqueous carboxylate solution at different sulfur dioxide partial pressures, a higher sulfur dioxide capture capacity is obtained at low sulfur dioxide partial pressures compared to example 1 of the present invention.

Examples 5,

1 g of tri-n-butyl-n-hexylphosphine 2-ethylhexanoate was taken, 10 g of water was added, a mixed gas of sulfur dioxide and nitrogen (sulfur dioxide partial pressure 0.001MPa, nitrogen partial pressure 0.099 MPa) was introduced at a rate of 300 ml/min for 2 minutes and 30 minutes, and the mixture was stirred continuously. The amount of absorbed sulfur dioxide was 0.10, 0.11 grams as determined by iodometry. The carboxylate aqueous solution has high absorption speed on sulfur dioxide.

Claims

1. Use of a carboxylate salt in any one of:

1) Capturing sulfur dioxide;

2) Preparing an absorbent for capturing sulfur dioxide;

the carboxylate anions in the carboxylate are carboxylate radicals with carbon chains with the carbon number more than 6, and the cations are substituted quaternary ammonium ions and/or substituted quaternary phosphonium ions;

the carboxylate with the carbon chain with the carbon number more than 6 is at least one of 2, 2-dimethyl hexanoate, 2-ethyl heptanoate, 2-propyl pentanoate and 2-propyl hexanoate;

the structural formulas of the substituted quaternary ammonium ion and the substituted quaternary phosphonium ion are respectively shown as the following formulas I and II:

formula I formula II

In the formulas I and II, n is an integer of 4 to 16, and the substituents in the formulas I and II are the same or different.

2. Use according to claim 1, characterized in that: in the formula I, n is an integer of 4 to 6;

in the formula II, n is an even number from 4 to 16.

3. A method for capturing sulfur dioxide using a carboxylic acid salt, comprising the steps of: introducing gas containing sulfur dioxide into the carboxylate or the water solution of the carboxylate to enable the gas to absorb the sulfur dioxide, so as to obtain a combination of the carboxylate and the sulfur dioxide separated out from the water, and realize the capture of the carboxylate on the sulfur dioxide;

wherein, the carboxylic acid anion in the carboxylate is carboxylate with carbon chain with carbon number more than 6, and the cation is substituted quaternary ammonium ion and/or substituted quaternary phosphonium ion;

formula I formula II

In the formulas I and II, n is an integer from 4 to 16, and the substituent groups in the formulas I and II are the same or different.

4. The method of claim 3, wherein: the mass ratio of the carboxylate to water is 1 to 10, and 0 is not included;

the conditions for absorbing sulfur dioxide are as follows: the partial pressure of sulfur dioxide in the gas containing sulfur dioxide is 0.0001 to 0.1MPa; the temperature is 25 to 80 ^o C。

5. The method according to claim 3 or 4, characterized in that: the absorption capacity of the carboxylate to sulfur dioxide is 0.028-0.205 g per gram.