JPH0571521B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> This invention relates to a hydrogen gas generating agent that generates hydrogen gas bubbles when it comes into contact with seawater. <Prior _art > Sodium borohydride (NaBH ₄ ), cobalt chloride (CoCl ₂ ),
Nickel chloride (NiCl ₂ ) Rhodium chloride (RhCl ₂ )
Or a mixture with platinum oxide catalyst etc., especially
A mixture of NaBH ₄ and CoCl ₂ has been used since the 1940s to the present. (From the cited document. The name of the cited document is listed at the end of this specification.) For example, approximately 1.5 g of a solid H ₂ generator consisting of two components, NaBH ₄ and 5 to 10 wt% anhydrous CoCl ₂ , is When brought into contact with 5 to 800 times the amount of water, a large amount of H ₂ is produced in a short period of about 10 minutes. (Cited document) This reaction is thought to proceed according to the following equations (1) and (2), and (Cited document) A large amount of about 4 mol per 1 mol of NaBH ₄ (about 2.2 m ³ per 1 kg of generator) is generated. It generates H ₂ efficiently. 2NaBH ₄ +CoCl ₂ +3H ₂ O →6.25H ₂ +0.5Co ₂ B+2NaCl+1.5HBO ₂ ...(1) NaBH ₄ +2H ₂ O→4H ₂ +NaBo ₂ ...(2) <Problem to be solved by the invention> However , the inventors of the present application have discovered that in the above reaction,
It was observed that the use of seawater as the _H2O source significantly suppressed _H2 generation. That is, it has been found that the above-mentioned H ₂ generator cannot be used in a situation where ordinary water such as tap water or distilled water is not available. As a means to solve this problem, (1) conventional
A means of always carrying regular water together with the H ₂ generator (2) For example, it is easy to consider a means of carrying an aqueous NaBH ₄ solution and an aqueous CoCl ₂ solution separately and mixing them at the time of use. However, it is very inconvenient from a practical point of view, such as the weight to be carried and the volume of the H ₂ generating agent, and the H ₂ generating device using it also becomes complicated. <Object of the invention> The object of the invention is to provide a chemical that reacts with seawater and generates a large amount of hydrogen gas. <Summary of Means> In short, this invention uses elements of group a of the periodic table and group b of the periodic table.
A hydrogen gas generating agent consisting of a hydrogen complex compound with a group element, one or more compounds of transition metal elements whose standard electrode potential is nobler than zinc ion (Zn ²⁺ ), and one or more chemicals that soften hard water. characterized by something. <Means for solving the problem> The inventors of the present application have studied in detail the reaction between NaBH ₄ and seawater, and have developed a novel H2O that easily generates _H2 using seawater of various salinities as a _H2O source. ₂ generator was discovered and the present invention was completed. That is, as the first component of a hydrogen complex compound of an element of group A and an element of group B of the periodic table.
NaBH ₄ has a second component whose standard electrode potential is more noble than that of zinc ions (Zn ²⁺ +2e ^- = Zn, Eo = -
0.763V) (Cited document) One or more compounds of transition metal elements or compounds containing platinum metals, and boric acid, boron oxide, or a hard water softener as a third component of a hard water softening agent. The above object can be achieved by using an H ₂ generator consisting of one or more selected from the following. In addition, the above means replaces NaBH ₄ as the first component with a similar hydrogen compound such as lithium borohydride (LiBH ₄ ), potassium borohydride (KBH ₄ ), or lithium aluminum hydride (LiAlH ₄ ).
It is also effective when <Examples> Prior to describing individual examples, these will be summarized below. The second component in this H ₂ generator includes halides, sulfates, nitrates, acetates, and hydroxides such as manganese, iron, cobalt, nickel, copper, panadium, ruthenium, rhodium, palladium, osmium, iridium, and platinum. Rhodium chloride (RhCl ₃ ), ruthenium chloride (RuCl ₃ ), platinum chloride (PtCl ₄ ), cobalt chloride (CoCl ₂ ), cobalt bromide (CoBr ₂ ), and iodide can be used. Cobalt (CoI ₂ ), Cobalt sulfate (CoSO ₄ ),
Cobalt acetate (Co(CH ₃ COO) ₂ ), cobalt hydroxide (Co(OH) ₂ ), nickel chloride (NiCl ₂ ), nickel nitrate (Ni(NO ₃ ) _{2 )} , osmium oxide (OsO ₄ ), etc. are effective. In other words, it is a compound of a transition metal element whose standard electrode potential is nobler than that of zinc ion. Zinc chloride (ZnCl ₂ ) was also effective, but chromium chloride (CrCl ₂ ) had almost no effect. .Standard electrode voltage of zinc ion (Zn ²⁺ +2e=Zn,
The standard electrode potential of divalent chromium ion (Cr ²⁺ +2e=Cr, E ⁰ =-0.79V) is more base than E ⁰ =-0.763V). Therefore, a compound of metal ions nobler than the standard electrode potential of zinc ions is considered to be effective as the second component in the present H ₂ generator. Further, as the second component, palladium carbon,
Noble metal group catalysts such as palladium black and platinum black are also effective. Furthermore, as the third component of boric acid, orthoboric acid (H ₃ BO ₃ ) and metaboric acid (HBO ₂ ) are effective, and as a water softener, sodium carbonate (Na ₂ CO ₃ ) is effective.
trisodium phosphate (Na ₃ PO ₄ ), sodium metaphosphate ((NaPO ₃ ) n: n>3), potassium metaphosphate ((KPO ₃ ) n), ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA) or oxalic acid, Effective are compounds that precipitate calcium ions in seawater as insoluble compounds, such as tartaric acid and its salts, or produce chelate compounds to block the interfering effects of the ions. Example 1 (See Tables 1 and 2) Predetermined amounts of NaBH ₄ , anhydrous CoCl ₂ and H ₃ BO ₃ were thoroughly mixed using a mortar in a dry box at a temperature of 25°C and a relative humidity of 20%. ₄ 65-95% by weight,
_{A H2} generator was prepared with 5% by weight of anhydrous _CoCl2 and 0-30% by weight of _H3BO3 . After filling 1.0 g of the H ₂ generator obtained in this way into a glass pear-shaped flask with an internal capacity of 50 ml as a reactor, 3 ml of actual seawater was added and the generated H ₂ was measured over time using a wet gas meter. Measured to
The results shown in Table 1 were obtained. Note that the initial water temperature in the table is the temperature of each water added, and the maximum water temperature is the maximum value of seawater temperature measured during the reaction. As shown in experiment number 1, in the _H2 generator
In the absence of H ₃ BO ₃ , H ₂ production is significantly suppressed. On the other hand, as the amount of H ₃ BO ₃ increases, the rate of H ₂ production becomes faster. Furthermore, in this example, as the reaction progressed, an increase in water temperature due to reaction heat was observed. For comparison and reference, Table 2 shows a solution of 2.72% by weight NaCl dissolved in standard seawater, distilled water, tap water, and, for example, distilled water, using the H ₂ generator having the composition of experiment number 1 of this example. Here, it is written as NaCl2.72%H ₂ O)
The experimental results were shown when 3 ml of the following were added. In distilled water, tap water, NaCl2.72% H ₂ O, etc., H ₂ can be generated efficiently in a short time as with conventional known technology even if the H ₂ generating agent does not contain H ₃ BO ₃ . do. In contrast, standard seawater or _CaSO4 or
It was observed that when CaCl ₂ was dissolved in distilled water, the production of H ₂ was significantly suppressed. Furthermore, a 0.2% solution of barium chloride (BaCl ₂ ) also significantly suppressed H ₂ production, similar to the CaSO ₄ solution. Furthermore, PH is added to the H ₂ generator with the composition of realization number 1.
Although 3 ml of actual seawater varied in the range of 2.2 to 10.3 was added, the result was similar to that of realization number 1 in Table 1.

【table】

【table】

[Table] Example 2 (see Table 3) NaBH ₄ 60~ prepared in the same manner as Example 1
100% by weight, anhydrous CoCl ₂ 0-30% by weight, H ₃ BO ₃ 0 or 10% by weight of H ₂ generator 1.0 g to 3 ml of real seawater at 15°C
Table 3 shows the results when adding . In this experiment, the reactor was cooled to prevent the rise in water temperature caused by the reaction heat observed in Example 1. Any anhydrous
Even in the CoCl ₂ content, the presence of H ₃ BO ₃ promotes H ₂ production.

【table】

[Table] Example 3 (see Table 4) 80% by weight of NaBH ₄ prepared in the same manner as in Example 1, 10% by weight of anhydrous CoCl ₂ and a third material other than H ₃ BO ₃
Results when 3 ml of actual seawater at 15°C was added to 1.0 g of the H ₂ generator corresponding to Experiment No. 24 in Table 3 containing 10% by weight, and the reaction was carried out while cooling the reactor as in Example 2. are shown in Table 4. In the presence of compounds used as water softeners, Examples 1 to 2
As in the case of H ₃ BO ₃ shown in , H ₂ production was significantly promoted, but sodium acetate (CH ₃ COONa) and sodium sulfate (Na ₂ SO ₄ ), which are thought to have little water softening effect, had little effect. I couldn't help it. Example 4 (see Table 5) NaBH ₄ prepared in the same manner as in Example 1 was 80
1.0 g of an H ₂ generator consisting of 10% by weight of the second component other than anhydrous CoCl ₂ and 10% by weight of sodium metaphosphate ((NaPO ₄ ) _o ) as the third component.
The results obtained when 3 ml of actual seawater was added to the water and reacted while cooling the reactor as in Example 2 are shown in the fifth example.

【table】

[Table] Shown in the table. The total amount of hydrogen produced was 1.82-1.86/g. In the second component other than CrCl ₂ , H ₃ BO ₃
Alternatively, the effect of adding (NaPO ₄ ) _o is significant.
In addition, the reaction completion time was 3 to 5 times longer in the case where (NaPO ₄ ) _o was not included.

【table】

[Table] Example 5 (see Table 6) NaBH ₄ 80% by weight, anhydrous CoCl ₂ 10% by weight,
Add 10% of seawater at 0 to 50°C to an _H2 generator with the same composition as Experiment No. 24 in Table ₃ , which consists of 10% by weight of _H3BO3 .
Table 6 shows the results obtained by adding 1.0 ml of each sample and carrying out the reaction while maintaining the respective temperatures. Although the reaction completion time becomes longer at a low temperature of 0°C, there is no change in the total amount of _H2 produced, making it effective even in seawater at low temperatures.
Can be an _H2 generator.

【table】

[Table] Example 6 (See Table 7) After preparing 30 g of H ₂ generator having the composition of Example 5 using a ball mill with a capacity of 100 ml in a nitrogen atmosphere,
Approximately 1.0 g was taken out, and a cylindrical tablet was prepared by varying the compression pressure using a cylindrical molding device with an inner diameter of 10 mmφ. This tablet was used in the same manner as in Example 5.
Table 7 shows the results when 10 ml of real seawater at 15°C was added. It was found that by forming into a tablet, the bulk density of the H ₂ generator increases, the amount of H ₂ produced per unit volume of the H ₂ generator increases, and the production of H ₂ is also promoted.

[Table] Example 7 (see Table 8) 1 g or 200 H ₂ generator with the same composition as in Example 5
Table 8 shows the results when 1 ml to 1 m ³ of actual seawater at 15° C. was charged with 1 ml to 1 m 3 of actual seawater. Note that a reactor corresponding to the actual amount of seawater was used. If the ratio between the actual amount of seawater and the H ₂ generator is as small as 1 ml/g, H ₂ generation will stop midway. From this example and the above examples, H ₂
To efficiently generate H 2 , it is sufficient to use approximately three times the amount of seawater as the amount of H ₂ generating agent.

[Table] Example 8 (see Table 9) In the H ₂ generator of Example 5, NaBH ₄ was
LiBH ₄ or KBH ₄ or LiAlH ₄ 80% by weight,
An otherwise similar H ₂ generator was prepared under dry nitrogen and added to 10 ml of seawater at 15° C. in the same manner as in Example 5. The results are shown in Table 9. In both cases NaBH ₄
H ₂ was generated as efficiently as in the case of . In addition, for those that do not contain H ₃ BO ₃ , the reaction completion time is 3 times longer for LiBH ₄ , 10 times longer for KBH ₄ ,
In LiAlH ₄ , it was 1.5 times.

[Table] Example 9 (see Table 10) Similar experiment number 4 in Table 1 in Example 1
The H ₂ generator shown in the comparative reference example of Example 1
Table 10 shows the results when 3 ml of a solution of CaSO ₄ , CaCl ₂ or BaCl ₂ dissolved in distilled water was added in the same manner as in Example 1. The solution used in this experiment was hard water corresponding to a German hardness of 50 to 60. Comparing the results of this example with the comparative reference example of Example 1, the present invention is obtained.
It is clear that H ₂ generators are effective not only in seawater but also in highly hard water.

[Table] <Function> The composition of the H ₂ generator according to the present invention is as follows:
60 to 90% by weight, especially 70 to 85% by weight of NaBH ₄ etc. is desirable, and the second component (e.g. CoCl ₂ , NiCl ₂ etc.)
is suitably 3 to 30% by weight, particularly 5 to 25% by weight, and the third component (H ₃ BO ₃ , NaCO _{3 ,} etc.) is preferably in the range of 5 to 20% by weight. If the second and third components are too small, the H ₂ production rate will be extremely slow and there will be no effect, while if they are too large, the proportion of NaBH ₄ in the H ₂ generator will decrease, resulting in a reduction in the H ₂ generator unit weight or The total amount of H ₂ produced per unit volume decreases, making it impractical. The _H2 generator mentioned above is a hydride such as _NaBH4 ,
It is adjusted by mixing the components and the third component in a ball mill or flush mill in an atmosphere of inert gas such as nitrogen or argon, dry air, etc., but it is preferable that the overall particle size is 0.5 mm or less. . If the particle size is large, the effect of adding the third component may be reduced. prepared by these methods
The H ₂ generator can be used as it is in powder form, but it can also be made into tablets by compression molding. Particularly, when there is a restriction on the capacity of the H ₂ generator, forming the H ₂ generator into a tablet is preferable because it increases the bulk density of the H 2 generator and increases the total amount of H ₂ produced per unit volume. In addition, during compression molding, use graphite or zinc stearate as a mold release agent.
3wt% may be added. In the present invention, when the H ₂ generating agent is poured into seawater, or when seawater is injected into the H ₂ generating agent, a weight ratio of 2 or more is sufficient for the ratio of seawater to the H ₂ generating agent. Note that the amount of H ₂ produced in the example is a value calculated using the following formula. V _s = 273/273 + t×P _a +P _n −P _v /760 where, V _s : H ₂ production amount ( ) V : Measured value with wet gas meter ( ) t : Temperature in wet gas meter (°C) P _a : Atmospheric pressure (mmHg) P _n : Gauge pressure in wet gas meter (mmHg) P _v : Saturated water vapor pressure at t°C (mmHg) The total amount of H ₂ produced is the amount of H ₂ produced until H ₂ production is no longer recognized. The integrated value is shown based on the weight of the H ₂ generating agent, and the reaction completion time is the reaction time until no H ₂ generation is observed. Furthermore, standard seawater is a total of 35.0g of the following salts dissolved in 965g of distilled water. NaCl: 27.213g MgCl ₂ : 3.807g MgSO ₄ : 1.658g CaSO ₄ : 1.260g K ₂ SO ₄ : 0.863g CaCO ₃ : 0.123g MgBr ₂ : 0.076g Actual seawater is seawater collected from the Pacific coast.
The pH is 7.8 at 15℃. <Effects> According to the present invention, an H ₂ generator that easily generates H ₂ even in seawater or hard water with a high Ca ²⁺ concentration can be obtained, so it can be used widely in areas where conventional technology is difficult. be. (Note) References J.Am.Chen.Soc., 75, 215 (1953) Ing.Eng.Chen.52(3), 211 (1960) J.Chem.Soc.Dalton Trans., 1985, 307 Rev. 3 Edition Chemistry Handbook Basic Edition, p473
(1984)

Claims (1)

[Scope of Claims] 1. A complex metal hydride compound of an element of group A and an element of group B of the periodic table, and one or more compounds of a transition metal element whose standard electrode potential is nobler than zinc ion (Zn ²⁺ ); A hydrogen gas generating agent characterized by being one or more types of chemicals that soften hard water. 2 The elements of Group A of the periodic table are Li, Na, K, the elements of Group B are B or Al, and the transition elements are Mn, Fe, Co, Ni, V, Cu,
The hydrogen gas generating agent according to claim 1, characterized in that it is Rh, Pd, Ru, Cs, Ir, or Pt. 3 The hard water is seawater, and the softening agent is boric acid, boron oxide,
The hydrogen gas generating agent according to claim 1, characterized in that it is any one of phosphate, nitrilotriacetic acid, oxalic acid, tartaric acid, and salts thereof. 4 60 to 90% by weight of the first component, which is a hydrogen complex compound of an element in group A of the periodic table and an element in group B, and 5% by weight or more of the second component, which is a compound of a metal ion of a transition metal element nobler than zinc ion. 2. The hydrogen gas generating agent according to claim 1, wherein the third component, which is a chemical that softens hard water, is comprised of 5% by weight or more. 5. The hydrogen gas generating agent according to any one of claims 1 to 4, wherein each of the first component, second component, and third component has a particle size of 0.5 mm or less. 6. The hydrogen gas generating agent according to any one of claims 1 to 4, characterized in that a mixture of the first component, second component, and third component is formed into a tablet. 7. The hydrogen gas generating agent according to claim 6, wherein 1 to 3% by weight of a mold release agent is added during compression molding.