JP4689417B2 - Carbon dioxide absorbent - Google Patents

Description

  The present invention relates to a gaseous carbon dioxide (carbon dioxide) absorbent (hereinafter referred to as a carbon dioxide absorbent) used for purification of respiratory gas and anesthetic gas.

  As an absorbent for carbon dioxide in respiratory gas and anesthetic gas, those mainly composed of calcium hydroxide, alkali metal hydroxide or / and alkaline earth metal hydroxide other than calcium and water are widely used. ing.

  However, an absorbent of such composition may be used in a respiratory gas containing an anesthetic such as fluoro-1,1,1,3,3,3-hexafluoro-2-propyl ether (sevoflurane), i.e. in anesthetic gas. When used to absorb carbon dioxide, there is a problem that a part of the anesthetic decomposes and the decomposition product is mixed in the anesthetic gas. The calcium hydroxide, alkali metal hydroxide or / and alkaline earth metal hydroxide other than calcium and water as a main component are contained in the absorbent according to absorption of carbon dioxide gas. The acid-alkali indicator develops or changes color. However, if left unattended, it will eventually return to its original color and it will not be possible to determine whether sufficient carbon dioxide absorption capacity remains. For this reason, carbon dioxide absorption ability has been reduced, or the use of an absorbent that has been dried by use has resulted in inadequate removal of carbon dioxide, or dangerous problems caused by anesthetic gas decomposition or abnormal heat generation. It has occurred.

  Under such circumstances, a carbon dioxide gas absorbent characterized by using a magnesium compound in order to solve the problem that a part of the anesthetic is decomposed and the decomposition product is mixed in the anesthetic gas (patented) Reference 1) has been developed. That is, the cause of such a problem is considered to be calcium hydroxide, which is the main component of the carbon dioxide absorbent as described above, or an alkali metal hydroxide, etc., and magnesium instead of calcium hydroxide. This is a carbon dioxide absorbent using a compound. However, the carbon dioxide absorbent characterized by using a magnesium compound has a problem that the production cost is higher than that of a carbon dioxide absorbent containing calcium hydroxide as a main component.

  In addition, as a result of examining the decomposition reaction of an anesthetic by a conventional carbon dioxide absorbent, the present inventors have found that soda lime (soda lime) conventionally used as a carbon dioxide absorbent, for example, sodium hydroxide In addition, when an alkali metal hydroxide such as potassium hydroxide is a cause of decomposing anesthetics, and when a carbon dioxide absorbent containing calcium hydroxide and water as a main component substantially free of these is prepared, It was found that a carbon dioxide gas absorbent capable of maintaining a high carbon dioxide absorption capacity and having little decomposition of sevoflurane, an anesthetic agent, and capable of reducing costs and simplifying the manufacturing process, was applied for a patent earlier. (Patent Document 2).

JP-A-5-57182 Japanese Patent No. 3433493

  The present invention has been made in view of the situation as described above, and has a high carbon dioxide absorption capacity, and is capable of reducing the cost and simplifying the manufacturing process with little decomposition of anesthetics such as sevoflurane. The object is to provide an absorbent.

The present invention comprises calcium hydroxide, water, 0.3 to 1.4 w / w% calcium chloride and 0.3 to 1.4 w / w% sodium chloride, and an alkali metal hydroxide. Further, the present invention is an invention of a carbon dioxide absorbent characterized in that it contains less than the extent that sevoflurane is not decomposed by these actions.
Moreover, this invention is invention of the carbon dioxide gas removal method in anesthetic gas characterized by processing respiration gas and anesthetic gas using the said carbon dioxide absorbent.

  That is, in view of the problems as described above, the present inventors have examined the decomposition reaction of an anesthetic with a conventional carbon dioxide absorbent, and are contained in soda lime that has been conventionally used as a carbon dioxide absorbent. For example, when alkali metal hydroxides such as sodium hydroxide and potassium hydroxide cause anesthetics to decompose, and when a carbon dioxide gas absorbent is prepared with calcium hydroxide and water as the main components that do not substantially contain these In addition, the present inventors have found that a carbon dioxide gas absorbent capable of maintaining a high carbon dioxide absorption capacity, having little decomposition of anesthetics such as sevoflurane, and capable of reducing the cost and simplifying the production process can be obtained. As a result of further earnest research, when carbon dioxide absorbent containing calcium hydroxide and water as a main component contains 0.3 to 1.4 w / w% of calcium chloride, the decomposition of sevoflurane and the like is further reduced. The present inventors have found that a carbon dioxide absorbent having a small amount and a further excellent carbon dioxide absorption capacity can be obtained, and completed the present invention.

  According to the present invention, compared with a carbon dioxide absorbent containing a conventional calcium hydroxide and an alkali metal hydroxide, or a carbon dioxide absorbent containing only calcium hydroxide and water as active ingredients, carbon dioxide Thus, a carbon dioxide gas absorbent is obtained that maintains a high absorption capacity and has little decomposition of an anesthetic such as sevoflurane. Also, as the acid / alkaline indicator contained in the absorbent develops or changes color as carbon dioxide is absorbed and consumed, it is easy to determine whether the absorbent is exhausted or absorbable because the color persists. I understand. Further, there is no danger of abnormal heat generation or harmful components due to the use of an exhausted or dried absorbent after use.

  Furthermore, since the carbon dioxide absorbent of the present invention contains sodium chloride, the carbon dioxide absorption retention time can be further increased. Also, it is not necessary to make the particle size extremely fine to increase the total surface area. For example, when preparing a tablet type, the size can be increased. The lock time can be shortened and the production cost can be suppressed.

The carbon dioxide absorbent of the present invention includes calcium hydroxide, water, 0.3 to 1.4 w / w% calcium chloride (as an anhydride), and 0.3 to 1.4 w / w% sodium chloride. It is characterized by containing.

  The carbon dioxide absorbent preferably does not contain an alkali metal hydroxide, but is particularly problematic if the concentration is below the level at which sevoflurane is not decomposed by the action of the alkali metal hydroxide. There is no.

  The specific concentration of alkali metal hydroxide allowed in the carbon dioxide absorbent is 0.01 w / w% or less, preferably 0.0075 w / w% or less in the absorbent. More preferably, it is 0.005 w / w% or less.

  Calcium hydroxide, calcium chloride, water, and more preferably sodium chloride added in the present invention are impurities that cause harmful and dangerous problems when used as an absorbent for carbon dioxide in respiratory gas, or May be any material that does not substantially contain an alkali metal hydroxide having the property of decomposing an anesthetic (contains no more than the extent that sevoflurane or the like is not decomposed by the action thereof), and particularly high purity. However, in the case of calcium hydroxide, for example, it is usually 95% or more in purity, preferably 97% or more in purity. In addition, calcium chloride can be used in an anhydrous form or in an appropriate hydrate (eg, monohydrate, dihydrate, etc.). When anhydrous calcium hydroxide is used, the purity is usually 95% or more, and when calcium hydroxide dihydrate is used, the purity is usually 70%. Sodium chloride usually has a purity of 94% or more, preferably 99% or more.

  Since alkaline earth metal hydroxides do not have the property of decomposing anesthetics, alkaline earth metal hydroxides such as magnesium hydroxide are present in the carbon dioxide absorbent of the present invention. There is no particular problem even if you do.

  The content of each component contained in the carbon dioxide absorbent of the present invention is such that calcium chloride is dihydrated in the absorbent in an amount of 0.5 to 1.8 w / w%, preferably 0.7 to 1.8 w / w%, more preferably 1.0 to 1.8 w / w%, ie 0.3 to 1.4 w / w% as anhydrous calcium chloride, preferably 0.5 to 1.4 w / w% More preferably, it may be contained in an amount of 0.8 to 1.4 w / w%. Sodium chloride should be contained in an amount of 0.3 to 1.4 w / w%, preferably 0.5 to 1.2 w / w%, more preferably 0.7 to 1.0 w / w%. The amounts of calcium hydroxide and water are appropriately selected according to the amounts of calcium chloride and sodium chloride. For example, the content of calcium hydroxide is 77.8 to 89.7 w / w%, preferably 79.8 to 89. The range is 5 w / w%, more preferably 81.1 to 89.4 w / w%. Moreover, as a water | moisture content, it is 8-21 w / w% normally, Preferably it is 9-19 w / w%, More preferably, the range of 9-16 w / w% is mentioned.

  The carbon dioxide absorbent of the present invention containing sodium chloride described above preferably contains an acid-alkali indicator as an indicator for detecting the remaining ability of the carbon dioxide absorption ability. Specific examples of the acid-alkali indicator include acid-alkali indicators such as ethyl violet, crystal violet, brilliant green, acid green, titanium yellow, and chondlet. Of these, ethyl violet is most preferable in consideration of solubility in water, its toxicity, color change (color development mode), and the like. If such an acid-alkali indicator is contained in the carbon dioxide absorbent of the present invention, the carbon dioxide gas is absorbed and the degree of alkalinity of the absorbent itself decreases, in other words, the carbon dioxide absorption capacity decreases. As a result, the color of the carbon dioxide absorbent changes (color development or discoloration), and the replacement time of the absorbent can be determined appropriately with the naked eye.

  The concentration of the acid-alkali indicator in the case where the carbon dioxide absorbent of the present invention containing sodium chloride contains an acid-alkali indicator is about 0.002 to 0.025 w / w%, preferably 0.004 to 0.015 w. However, the concentration range is usually about 0.004 to 0.01 w / w%.

  As a preferable embodiment of the carbon dioxide absorbent containing sodium chloride of the present invention, calcium hydroxide is 81.1 to 89.4 w / w%, water is 9.0 to 16.0 w / w%, calcium chloride. Of carbon dioxide gas containing 0.8 to 1.4 w / w% of sodium chloride, 0.7 to 1.0 w / w% of sodium chloride, and 0.004 to 0.01 w / w% of an acid-alkali indicator. .

  Further, as another preferred embodiment of the carbon dioxide absorbent containing sodium chloride of the present invention, in the above-described embodiment, 84.65 to 84.75 w / w% of calcium hydroxide and calcium chloride are further added. Examples thereof include a carbon dioxide absorbent containing 1.31 w / w% and 0.91 w / w% sodium chloride.

  Examples of the shape of the carbon dioxide absorbent according to the present invention include granular (used to include granules and pellets; the same shall apply hereinafter) or tablet shape.

  The component content of the granular carbon dioxide absorbent of the present invention containing sodium chloride is calcium chloride (dihydrate) of 0.5 to 1.8 w / w%, preferably 0.7 to 1.8 w / w. %, More preferably about 1.0 to 1.8 w / w% (0.3 to 1.4 w / w% as anhydrous calcium chloride, preferably 0.5 to 1.4 w / w%, more preferably 0.5%). 8 to 1.4 w / w%) is preferable. Sodium chloride is preferably contained in an amount of 0.3 to 1.4 w / w%, preferably 0.5 to 1.2 w / w%, more preferably 0.7 to 1.0 w / w%. The content of calcium hydroxide depends on the concentrations of calcium chloride and sodium chloride, but is 77.8-89.7 w / w%, preferably 79.8-89.5 w / w%, more preferably 81.1. The range of -89.4 w / w% is mentioned. Moreover, as a water | moisture content, it is 8-21 w / w% normally, Preferably it is 9-19 w / w%, More preferably, the range of 9-16 w / w% is mentioned. Furthermore, if necessary, the concentration of the acid-alkali indicator to be contained may be about 0.002 to 0.025 w / w%, preferably about 0.004 to 0.015 w / w%. It is used in the range of about 0.004 to 0.01 w / w%.

  The carbon dioxide gas absorbent of the present invention can be prepared by a conventionally used method, that is, a method in which calcium hydroxide, calcium chloride, water and sodium chloride are mixed and then appropriately molded into a granular shape or the like. In the carbon dioxide absorbent prepared by such a method, the granules in the container rub against each other during transportation, and the uneven parts wear, resulting in fine powder or dusty calcium hydroxide. When calcium chloride, etc. is generated and a device equipped with a column packed with this as an absorbent is used, fine powder or dust such as calcium hydroxide and calcium chloride is carried out together with breathing gas and anesthetic gas, Patients who are inhaling may be seriously affected by inhalation, or when refilling the carbon dioxide absorbent, dust such as calcium hydroxide or calcium chloride is scattered inside the room. There is a possibility of contaminating the air, it is desirable to utilize the present inventors of certain et preparation of the carbon dioxide-absorbing agent developed by (JP-A-3-047533).

  In order to prepare the granular carbon dioxide absorbent of the present invention, for example, a commercially available calcium hydroxide granular (pellet-shaped) material may be used as it is, and the particle size may be adjusted. Moreover, you may use what was sized by a publicly known method so that one grain may become the same amount. When sizing, the sizing may be performed so that the amount of one grain is 1 to 550 mg, preferably 20 to 200 mg, and more preferably 30 to 100 mg. As a method of adding calcium chloride, water, sodium chloride and, if necessary, an appropriate acid-alkali indicator to the obtained calcium hydroxide granules, use a sugar coating machine, a coating pan, etc. Or, if necessary, a method of spraying a predetermined aqueous solution of an appropriate acid-alkali indicator may be mentioned.

  In addition, the granular carbon dioxide absorbent of the present invention does not need to have a constant weight or shape as in the case of the tablet-type carbon dioxide absorbent.

  Inhalation anesthetics to which the carbon dioxide absorbent of the present invention can be applied include sevoflurane, 2-chloro-1,1,2-trifluoroethyl difluoromethyl ether (enflurane), 1-chloro-2,2,2-trifluoro. There is no particular limitation as long as it contains ethyldifluoromethyl ether (isoflurane) or the like and is generally used as an anesthetic gas, but among them, a substance containing sevoflurane is typical.

  Since the carbon dioxide absorbent of the present invention can be prepared only with calcium hydroxide, calcium chloride, water and sodium chloride, like conventional ones such as sodium hydroxide, potassium hydroxide, magnesium hydroxide, barium hydroxide, etc. In addition, since there is no need to add and mix an alkali metal hydroxide, an alkaline earth metal hydroxide or the like, there is also an advantage that the production process is simplified. In addition, the calcium hydroxide used in the carbon dioxide absorbent of the present invention can be purchased at a lower cost than a magnesium compound such as magnesium hydroxide, so carbon dioxide absorption using magnesium hydroxide or the like can be purchased. There is also an advantage that the manufacturing cost can be reduced compared to the agent.

  In addition, when producing (molding) a carbon dioxide absorbent, attempts have been made to increase the carbon dioxide absorption efficiency by reducing the size of tablets or granules, but the carbon dioxide absorbent of the present invention is Even if the diameter is increased, a product having a long carbon dioxide absorption capacity retention time can be produced. For example, when sodium chloride is not contained, a carbon dioxide absorbent having a diameter of 4 mm has a longer carbon dioxide absorption capacity retention time than a carbon dioxide absorbent having a diameter of 5 mm. On the other hand, by containing sodium chloride, a carbon dioxide absorbent having a diameter of 5 mm can have a longer carbon dioxide absorption capacity retention time than a carbon dioxide absorbent having a diameter of 4 mm and a diameter of 5 mm that does not contain sodium chloride. In actual use, there is no difference in usability such that a diameter of 5 mm is more difficult to handle than a diameter of 4 mm, but the latter generally has an advantage of less circulation resistance to breathing. Furthermore, when a carbon dioxide absorbent is molded from the same amount of material by making the diameter larger, it is natural that molding a 5 mm diameter is easier than molding a 4 mm diameter. (Tabletting time) can be shortened, and as a result, there is an excellent effect that the manufacturing cost does not increase.

  In addition, the carbon dioxide gas removal method of the present invention uses the carbon dioxide gas absorbent of the present invention as described above to treat respiratory gas and anesthetic gas by a method usually used in this field [for example, an anesthesia canister (carbon dioxide gas Anesthetic gas is passed through a column filled with the carbon dioxide absorbent of the present invention. As the anesthetic gas, those mentioned above are preferable.

  Hereinafter, the present invention will be described in more detail with reference to reference examples, examples, and comparative examples, but the present invention is not limited thereto.

Reference example 1
(1) Preparation of Carbon Dioxide Absorber Powdered calcium hydroxide (Ca (OH) ₂ , Wako Pure Chemical Industries, Ltd., purity 97.5%) was used with a commercially available tableting machine, and tableting hardness 250 g Was formed into a tablet having a diameter of 4 mm and a height of 2.3 mm. The obtained tablets are put on a commercially available sugar coating machine, and calcium chloride dihydrate (CaCl ₂ · 2H ₂ O, manufactured by Wako Pure Chemical Industries, Ltd.) and ethyl violet are prescribed concentrations with respect to 84 w / w% of tablets. The dissolved aqueous solution was sprayed at a rate of 16 w / w%. Next, the product sealed in a plastic bag is left in an incubator at 80 ° C. for 15 hours, and the hardness is set to 900 g by sealed heat aging, and the tablet type having four compositions as shown in Table 1 is used. A carbon dioxide absorbent was obtained. The water content (w / w%) in the obtained carbon dioxide absorbent was measured and found to be 15 w / w%. The ethyl violet content was 0.016 w / w%.

  In Table 1, No. 1 tablet is a conventional carbon dioxide absorbent containing calcium hydroxide and water. No. 2 to No. 4 are carbon dioxide gas absorbents of Reference Example 1 containing calcium hydroxide, water and calcium chloride. Moreover, the content of calcium chloride as anhydrous calcium chloride is 0.378 w / w% for No.2, 0.604 w / w% for No.3, and 0.906 w / w% for No.4.

(2) Carbon dioxide absorption ability test The carbon dioxide absorption ability test of each carbon dioxide absorbent obtained in the above (1) was performed according to the following operation.
A canister (diameter 9 cm, height 15 cm) is filled with a carbon dioxide absorbent 810 g, and a mixed gas of oxygen and carbon dioxide (CO ₂ concentration 4.6%) is intermittently distributed to the canister (tidal volume: 400 mL, ventilation) Frequency: 15 times / minute), and the carbon dioxide concentration in the passed gas is measured with an infrared carbon dioxide analyzer (machine name BIR-200, manufactured by Best Sokki Co., Ltd.). The time to reach 0.10% (carbon dioxide absorption capacity retention time) was measured. A longer carbon dioxide absorption capacity retention time indicates that the carbon dioxide absorption capacity is maintained for a long time, that is, the carbon dioxide absorption capacity is high.
The results are shown by a line graph (-♦-) in FIG.

(3) Measurement of decomposition product generation rate of anesthetic agent Using the carbon dioxide absorbent obtained in (1) above, measurement of the decomposition product generation rate of anesthetic agent was performed according to the following operation.
Take 1 g of carbon dioxide absorbent in a 30 mL vial, add 1.5 mL of the anesthetic sevoflurane (trade name: Sevofurene ^TM , manufactured by Maruishi Pharmaceutical Co., Ltd.), seal it tightly, and let it react in a constant temperature bath at 40 ° C for 17 hours. Thereafter, 1 mL of the gas phase portion was collected, and the rate of decomposition product formation of the anesthetic sevoflurane was measured by gas chromatography. The analysis uses Shimadzu GC-14B gas chromatography, detector FID, carrier gas is He, flow rate is 50 mL / min, sample inlet temperature is 120 ° C., column thermostat temperature is 100 ° C., detector temperature is 180 ° C., H _2. The measurement was performed under the conditions of a flow rate pressure of 60 KPa and an air flow rate pressure of 50 KPa. Column is Dioctyl
A 3.2 mmφ × 2 m glass column packed with Phthalate 20% chromosorb W (AW-DMCS) 60/80 mesh was used.
The results are also shown in a bar graph in FIG.

  As apparent from FIG. 1, the carbon dioxide absorbent of Reference Example 1 containing calcium chloride is a conventional carbon dioxide absorbent containing only calcium hydroxide and water (in FIG. 1, calcium chloride dihydrate added). It retains the ability to absorb carbon dioxide for a longer period of time (when the amount is 0.0%) (line graph:-◆-), has a high ability to absorb carbon dioxide, and has a decomposition product rate of anesthetics ( %) (Bar graph) is clearly low.

  The content of calcium chloride dihydrate in the carbon dioxide absorbent is preferably 0.5 w / w% or more (0.378 w / w% as an anhydride), and 1.2% (anhydride). As a result, the carbon dioxide absorption capacity reaches a peak and is saturated, and the decomposition of the anesthetic is also equilibrated at a low value.

Example 1
(1) Preparation of carbon dioxide gas absorbent 30 kg of powdered calcium hydroxide (Ca (OH) ₂ , Wako Pure Chemical Industries, Ltd., purity 97.5%) and calcium chloride dihydrate (CaCl _2. 2H ₂ O (manufactured by Wako Pure Chemical Industries, Ltd.) 158 g was mixed well, and then a tablet having a tableting hardness of 250 g and a diameter of 5 mm and a height of 2.3 mm was molded using a commercially available tableting machine. The obtained tablets were put on a commercially available sugar coating machine, and calcium chloride dihydrate (CaCl ₂ · 2H ₂ O, manufactured by Wako Pure Chemical Industries, Ltd.) and sodium chloride (NaCl, Wako Pure Chemical Industries, Ltd., purity 99%) and an aqueous solution in which ethyl violet was dissolved at a predetermined concentration were sprayed at a rate of 13 w / w%. Next, the product sealed in a plastic bag is allowed to stand in a thermostat at 50 ° C. for 2 hours, and the hardness is set to 1100 g by sealed heating aging, and the tablet-type carbonic acid having five compositions as shown in Table 2 is used. A gas absorbent was obtained.
The water content (w / w%) in the obtained carbon dioxide absorbent was measured and found to be 13 w / w%. The ethyl violet content was 0.000045 w / w%.

  In Table 2, the No. 1 tablet is the carbon dioxide gas absorbent of Reference Example 1 containing calcium hydroxide, water and calcium chloride. No. 2 to No. 5 are carbon dioxide gas absorbents of the present invention containing calcium hydroxide, water, calcium chloride and sodium chloride. The amount of calcium chloride in each carbon dioxide absorbent is 1.31 w / w% as anhydrous calcium chloride, and the sodium chloride content is 0.39 w / w% for No.2 and 0.65 w for No.3. No. 4 is 0.91 w / w%, and No. 5 is 1.3 w / w%.

(2) Carbon dioxide absorption capacity test In the same manner as in Reference Example 1, the carbon dioxide absorption capacity test of the carbon dioxide absorbent obtained in (1) above was performed.
The results (carbon dioxide absorption capacity retention time) are shown by a line graph (-♦-) in FIG.

(3) Measurement of decomposition product generation rate of anesthetic agent The decomposition product generation rate of an anesthetic agent was measured in the same manner as in Reference Example 1 using the carbon dioxide absorbent obtained in (1) above.
The results are also shown in a bar graph in FIG.

  As is apparent from FIG. 2, the carbon dioxide absorbent containing calcium hydroxide, water, calcium chloride and sodium chloride of the present invention retains the ability to absorb carbon dioxide for a longer time (line graph: − ◆-), the ability to absorb carbon dioxide gas is high, and it can be seen that the rate of formation of anesthetic decomposition products (%) (bar graph) decreases.

  Further, the content of sodium chloride in the carbon dioxide absorbent is 0.3 w / w% or more, preferably 0.65 w / w%, and the addition of about 0.91 w / w% absorbs carbon dioxide. It can be seen that the performance reaches a peak and the anesthetic resolution is equilibrated at a low value.

Reference example 2
[Preparation of carbon dioxide absorbent]
Powdered calcium hydroxide (Ca (OH) ₂ , manufactured by Wako Pure Chemical Industries, Ltd., purity: 97.5%) was used with a commercially available tableting machine, with a tableting hardness of 250 g, a diameter of 4 mm, and a height of 2.3 mm. Into tablets. The obtained tablets were put on a commercially available sugar coating machine, and 5 w / w% calcium chloride dihydrate (CaCl ₂ · 2H ₂ O, manufactured by Wako Pure Chemical Industries, Ltd.) and 0 with respect to 84 w / w% of tablets. An aqueous solution containing 0.1 w / w% ethyl violet was sprayed at a rate of 16 w / w%. Next, this was sealed in a plastic bag, left in an incubator at 80 ° C. for 15 hours, and then sealed and aged to a hardness of 900 g to obtain a tablet-type carbon dioxide absorbent containing no sodium chloride. (Wet product). Table 3 shows the composition and shape of the obtained tablets.
The water content (w / w%) in the obtained carbon dioxide absorbent was measured and found to be 15 w / w%. The content of ethyl violet is 0.016 w / w%, and the calcium chloride content is 0.8 w / w% as dihydrate and 0.604 w / w% as anhydrous calcium chloride.
Further, the carbon dioxide absorbent obtained was dried in a thermostat until the water content became 1.0 w / w% or less, and this was designated as a dry product.

[Performance test of carbon dioxide absorbent]
The performance test of the carbon dioxide absorbent obtained above was performed as follows. The results are also shown in Table 3.
(1) Measurement of decomposition product formation rate of anesthetic agent The decomposition product generation rate (%) of anesthetic agent was measured in the same manner as in Reference Example 1 for wet products and dry products of carbon dioxide gas absorbent. The results are also shown in Table 3.

(2) Carbon dioxide gas absorption capacity test A carbon dioxide gas absorption capacity test was performed on the wet carbon dioxide gas absorbent by the same method as in Reference Example 1. The results are shown in Table 3 as “carbon dioxide absorption capacity retention time”.

(3) Measurement of the amount of carbon monoxide generated 1 g of dry carbon dioxide absorbent was placed in a 30 mL vial, and the anesthetics sevoflurane, enflurane (trade name: Etrene ^TM , manufactured by Dainippon Pharmaceutical Co., Ltd.) or isoflurane ( After adding 0.5 mL of Dainippon Pharmaceutical Co., Ltd. (trade name: Foren ^TM ), the bottle was sealed and allowed to react for 18 hours in a 37 ° C. constant temperature bath, and then a carbon monoxide meter (instrument) was placed in the mouth of the vial. Name TPA-5000 (manufactured by Mitsumeri Kagaku) was applied, and the amount of produced carbon monoxide was measured.
The results are shown in Table 3 as “CO generation amount (dry product)”.

(4) Exothermic test For carbon dioxide absorbent wet and dry products, a stainless steel column of 42 mmφ x 150 mm was filled with 150 g of carbon dioxide absorbent, a thermometer was installed in the center of the column, and anesthesia was performed at an oxygen flow rate of 1 L / min The drug sevoflurane was passed through the column at a concentration of 6.6%, enflurane at 7.2%, and isoflurane at a concentration of 7.1%, and the exothermic temperature was examined.
The results are shown as “Exotherm” in Table 3.

(5) Measurement of powder generation rate 10 g of precisely weighed carbon dioxide absorbent is put into a polypropylene container with a diameter of 30 mm and a length of 10 cm, tightly closed, tilted sideways, fixed on a reciprocating shaker (Yamato Scientific Co., Ltd.) and shaken. The mixture was shaken for 7 hours under the conditions of a width of 30 mm and a shaking speed of 120 times / min. This was sieved (12 mesh sieve, mesh size 1.4 mm), and the powder generation rate (w / w%) of 12 mesh or less was measured.

(6) Discoloration (discoloration) inspection after use 810 g of carbon dioxide absorbent is filled in a canister (diameter 9 cm, height 15 cm), and the canister is a mixed gas of oxygen and carbon dioxide (CO ₂ concentration 4.6%). Was intermittently distributed (tidal volume: 400 mL, ventilation rate: 15 times / min) over 4 hours. The carbon dioxide absorbent was collected, and the colored portion was measured for L ^* value (lightness%) of the color display mode (L ^* a ^* b ^* ) according to the protocol using a Minolta colorimeter CR-321. .
The measurement was performed on the carbon dioxide absorbent before the inspection, immediately after the inspection, and one day after the inspection.
The results are shown in Table 4.

Example 2
[Preparation of tablet-type carbon dioxide absorbent]
30 kg of powdered calcium hydroxide (Ca (OH) ₂ , manufactured by Wako Pure Chemical Industries, Ltd., purity 97.5%) and calcium chloride dihydrate (CaCl ₂ · 2H ₂ O, Wako Pure Chemical Industries ( 158 g) was mixed well, and then a tablet having a tableting hardness of 250 g and a diameter of 5 mm and a height of 2.3 mm was molded using a commercially available tableting machine. The obtained tablets were put on a commercially available sugar coating machine, and 10 w / w% calcium chloride dihydrate (CaCl ₂ · 2H ₂ O, manufactured by Wako Pure Chemical Industries, Ltd.) and 7 w with respect to 87 w / w tablets. / W% sodium chloride (NaCl, manufactured by Wako Pure Chemical Industries, Ltd., purity 99%) and 0.035 w / w% aqueous solution of ethyl violet dissolved in a predetermined concentration were sprayed at a ratio of 13 w / w%. Next, the product sealed in a plastic bag is allowed to stand in a thermostat at 50 ° C. for 2 hours, and the hardness is set to 1120 g by sealed heating aging to absorb the carbon dioxide gas of the tablet type containing sodium chloride of the present invention. An agent was obtained (wet product). Table 3 shows the composition and shape of the obtained tablets. The water content (w / w%) in the obtained carbon dioxide absorbent was measured and found to be 13 w / w%. The calcium chloride content was 0.435 w / w% in the initial powder mixture as a dihydrate and 1.3 w / w% by spray addition (total 1.735 w / w%, ie 1.31 w as anhydrous calcium chloride). / W%). The content of sodium chloride is 0.91 w / w%. The content of ethyl violet is 0.000045 w / w%.
Further, the carbon dioxide absorbent obtained was dried in a thermostat until the water content became 1.0 w / w% or less, and this was designated as a dry product.

[Performance test of carbon dioxide absorbent]
With respect to the obtained carbon dioxide absorbent, in the same manner as in Reference Example 2, measurement of the rate of decomposition of anesthetics, carbon dioxide absorption capacity test, measurement of carbon monoxide generation, exothermic test, powder generation rate Measurements were made. The results are also shown in Table 3.
Further, the fading (discoloration) after use was inspected by the same method as in Reference Example 2. The results are also shown in Table 4.

Comparative Example 1
After thoroughly mixing 3 kg of powdered calcium hydroxide and 140 g of granular sodium hydroxide, it was molded into a tablet having a tableting hardness of 250 g and a diameter of 5 mm and a height of 2.3 mm using a commercially available tableting machine. The obtained tablet was put on a commercially available sugar coating machine, and 0.075 w / w% ethyl violet aqueous solution was sprayed into the tablet 84 w / w% at a ratio of 16 w / w%. Next, the product sealed in a plastic bag was left in an incubator at 80 ° C. for 15 hours, and hermetically heated and aged to 1020 g to obtain a carbon dioxide absorbent. Table 3 shows the composition and shape of the obtained tablets.
The water content (w / w%) in the obtained carbon dioxide absorbent was measured and found to be 15 w / w%.
With respect to the obtained carbon dioxide absorbent, in the same manner as in Reference Example 2, measurement of the rate of decomposition of anesthetics, carbon dioxide absorption capacity test, measurement of carbon monoxide generation, exothermic test, powder generation rate Measurements were made. The results are also shown in Table 3.
Further, the fading (discoloration) after use was inspected by the same method as in Reference Example 2. The results are also shown in Table 4.

  As is clear from the results in Table 3, the carbon dioxide absorbent of the present invention is clearly lower in the rate of formation of an anesthetic decomposition product in both wet and dry products than the carbon dioxide absorbent of Comparative Example 1. It can be seen (Reference Example 2, Example 2). Furthermore, it turns out that an anesthetic decomposition product production rate becomes still lower by containing sodium chloride (Example 2).

The carbon dioxide absorbent (dry product) of Comparative Example 1 generated a large amount of carbon monoxide (CO) by contact with the anesthetic, but it was completely generated in the dry product obtained in Reference Example 2 and Example 2. I did not. In addition, as a result of measuring the amount of carbon monoxide generated using the wet products obtained in Reference Example 2 and Example 2, no carbon monoxide was generated as in the dry product. Have confirmed.
From the above, it can be seen that the carbon dioxide absorbent of the present invention is excellent particularly for absorbing carbon dioxide in anesthetic gas.

Furthermore, the carbon dioxide absorbent (dry product) of Comparative Example 1 generated heat of 30 ° C. or more when brought into contact with an anesthetic. However, the carbon dioxide absorbent of the present invention was anesthetic for both wet and dry products. No fever occurred when contacted with the drug.
Further, the generation rate of the carbon dioxide absorbent (wet product) of the present invention was lower than that of the carbon dioxide absorbent of Comparative Example 1.

Further, when using the carbon dioxide absorbent, it is convenient that it can be determined by color whether or not the carbon dioxide absorbent is dried.
As apparent from Table 3, the carbon dioxide absorbent of the present invention developed color by drying (Example 2), but the carbon dioxide absorbent of Comparative Example 1 did not develop color.

Further, as is apparent from Table 4, the carbon dioxide absorbent (Example 2) of the present invention was white before the inspection, but it developed a purple color immediately after the inspection that absorbed the carbon dioxide gas. It was kept even one day later. However, the carbon dioxide absorbent of Comparative Example 1 was white before use and colored purple immediately after absorbing the carbon dioxide, but after that, it faded and turned white after 1 day, and the carbon dioxide absorbent. It is not possible to determine whether the battery is exhausted or absorbable.
From these facts, it can be seen that the carbon dioxide absorbent of the present invention has a high capacity, is safe and easy to handle as compared with the conventional product.

  It should be noted that the carbon dioxide absorbent is dried during repeated use, but it was known that the use of this dried product caused problems such as a decrease in carbon dioxide absorption capacity, decomposition of anesthetic gas, and abnormal heat generation. It has been. The carbon dioxide absorbent (Example 2) of the present invention has low anesthetic decomposition product generation rate and carbon monoxide generation rate not only in wet products but also in dry products, and does not cause abnormal heat generation even when used. Has excellent features.

Reference example 3
Preparation of Tablet Type Carbon Dioxide Absorber Containing No Sodium Chloride Powdered calcium hydroxide (Ca (OH) ₂ , manufactured by Wako Pure Chemical Industries, Ltd., purity 97.5%) was used using a commercially available tableting machine. A tablet with a tableting hardness of 250 g and a tablet with a diameter of 4 mm and a height of 2.3 mm and a tablet with a diameter of 5 mm and a height of 2.3 mm were obtained. The obtained tablets are put on a commercially available sugar coating machine, and calcium chloride dihydrate (CaCl ₂ · 2H ₂ O, manufactured by Wako Pure Chemical Industries, Ltd.) 5 w / w% and ethyl are used for 84 w / w% of tablets. An aqueous solution containing violet 0.1 w / w% was sprayed at a rate of 16 w / w%. This was sealed in a plastic bag and allowed to stand in an incubator at 80 ° C. for 15 hours to obtain a tablet-type carbon dioxide absorbent. The composition of the obtained absorbent was 4 mm in diameter and 5 mm in diameter, calcium hydroxide 84 w / w%, water 15 w / w%, and calcium chloride dihydrate 0.8 w / w% ( Anhydrous calcium chloride is 0.604 w / w%). The content of ethyl violet is 0.016 w / w%.

Example 3
Preparation of Tablet-type Carbon Dioxide Absorber of the Present Invention Containing Sodium Chloride Powdered calcium hydroxide (Ca (OH) ₂ , Wako Pure Chemical Industries, Ltd., purity 97.5%) is commercially available. Using a machine, a tablet having a tableting hardness of 250 g and a diameter of 5 mm and a height of 2.3 mm was obtained. The obtained tablets with a diameter of 5 mm were put on a commercially available sugar coating machine, and 10 w / w% calcium chloride dihydrate (CaCl ₂ .2H ₂ O, manufactured by Wako Pure Chemical Industries, Ltd.) with respect to 89 w / w% of tablets. And 5 w / w% sodium chloride (NaCl, manufactured by Wako Pure Chemical Industries, Ltd., purity 99%) and an aqueous solution containing 0.035 w / w% ethyl violet were sprayed at a ratio of 11 w / w%. This was sealed in a plastic bag and left in a thermostat at 50 ° C. for 2 hours to obtain a tablet-type carbon dioxide absorbent.
In addition, when the water content (w / w%) in the obtained carbon dioxide absorbent was measured, it was 10 w / w% which was almost the same as the water content impregnated by the sugar coating machine. The calcium hydroxide content is 88 w / w%, the calcium chloride content is 1.0 w / w% as dihydrate and 0.755 w / w% as anhydrous calcium chloride. The content of sodium chloride is 0.5 w / w%. The content of ethyl violet is 0.000038 w / w%.

The carbon dioxide absorption ability test of the carbon dioxide absorbent obtained in Reference Example 3 and Example 3 was performed according to the following operation.
A canister (diameter 9 cm, height 15 cm) is filled with a carbon dioxide absorbent 810 g, and a mixed gas of oxygen and carbon dioxide (CO ₂ concentration 4.6%) is intermittently distributed to the canister (tidal volume: 400 mL, ventilation) Frequency: 15 times / minute), and the carbon dioxide concentration in the gas passed through was measured with an infrared carbon dioxide analyzer (machine name BIR-200, manufactured by Best Instrument Co., Ltd.).

The results are shown in FIG. In FIG. 3, the horizontal axis indicates the distribution time of the mixed gas, the vertical axis indicates the carbon dioxide concentration (CO ₂ passage concentration (%)) in the mixed gas that has passed through each distribution time, and − ● − Tablet type carbon dioxide absorbent with a diameter of 5 mm of Reference Example 3 (without addition of NaCl),-◯-is a carbon dioxide absorbent with a diameter of 4 mm of Reference Example 3 (with no addition of NaCl), and -Δ- is a diameter of 5 mm of Example 3. The results obtained for each tablet type carbon dioxide absorbent (containing NaCl, 0.5 w / w%) are shown.

As apparent from FIG. 3, the carbon dioxide gas absorbent having a diameter of 4 mm (without addition of NaCl) of Reference Example 3 has 0% of the passing carbon dioxide gas than the carbon dioxide gas absorbent of 5 mm of Reference Example 3 (without addition of NaCl). It can be seen that the carbon dioxide absorption capacity retention time is long and it is excellent as a carbon dioxide absorbent.
Further, as is apparent from FIG. 3, the carbon dioxide absorbent of the present invention further containing sodium chloride has a diameter of 4 to 4 of the carbon dioxide absorbent (non-NaCl) of Reference Example 3 even if it has a diameter of 5 mm. It can be seen that the absorption capacity retention time of 0% of the passing carbon dioxide gas is longer than that of the 5 mm carbon dioxide absorbent, and it is further excellent as a carbon dioxide absorbent.

  As described above, the present invention maintains a high ability to absorb carbon dioxide in respiratory gas and anesthetic gas as compared with a carbon dioxide absorbent containing conventional calcium hydroxide and alkali metal hydroxide. In addition, the present invention provides a carbon dioxide absorbent that reduces the cost and simplifies the manufacturing process because there is little decomposition of an anesthetic such as sevoflurane and the mixing operation of the material can be omitted. However, it is a great invention.

Relationship between calcium chloride concentration (calcium chloride addition amount (%)) in the tablet-type carbon dioxide absorbent obtained in Reference Example 1 and the rate of formation of an anesthetic decomposition product (%), and carbon dioxide absorption capacity It is a graph which shows the relationship with retention time (minutes). Relationship between sodium chloride concentration (addition amount of sodium chloride (%)) in the tablet-type carbon dioxide absorbent obtained in Example 1 and the rate of formation of anesthetic decomposition products (%), and carbon dioxide absorption capacity It is a graph which shows the relationship with retention time (minutes). The tablet-type carbon dioxide absorbent (with no NaCl added) having a diameter of 4 mm and 5 mm obtained in Reference Example 3 and the tablet-type carbon dioxide absorbent (containing NaCl) of the present invention having a diameter of 5 mm obtained in Example 3 were used. The relationship between the carbon dioxide absorption capacity retention time (minutes) in the mixed gas and the carbon dioxide concentration (CO ₂ passage concentration (%)) in the mixed gas, obtained by examining the carbon dioxide absorption capacity, is shown. It is a graph.

Explanation of symbols

In FIG. 4, − ● − is a tablet-type carbon dioxide absorbent (diameter not added) having a diameter of 5 mm, − ◯ − is a carbon dioxide absorbent (no NaCl) of the present invention having a diameter of 4 mm, and −Δ− is a diameter. The results obtained for a 5 mm tablet-type carbon dioxide absorbent (containing 0.5 w / w% NaCl) are shown respectively.

Claims (5)

Contain calcium hydroxide and water and 0.3~1.4w / w% of calcium chloride and 0.3~1.4w / w% sodium chloride, and 0.01w a hydroxide of an alkali metal / Carbon dioxide absorbent characterized by containing only w% or less. The carbon dioxide gas absorbent according to claim 1, further comprising an acid-alkali indicator. The carbon dioxide gas absorbent according to claim 1 or 2, which contains 77.8 to 89.7 w / w% of calcium hydroxide. The carbon dioxide absorbent according to any one of claims 1 to 3, wherein the solid absorbent is granular or tablet-shaped. A method for removing carbon dioxide from an anesthetic gas, wherein the breathing gas or anesthetic gas is treated using the carbon dioxide absorbent according to any one of claims 1 to 4.