By TRUNNANO | 26 April 2021 | 0 Comments
CaH2 is a brine hydride which means it has a salt-like structure
Overview of calcium hydride
The chemical formula for calcium hydride is CaH2.Molecular weight 42.1.White rhombic crystal. The melting point is 816℃(in a hydrogen stream), decomposition is about 600℃, and the relative density is 1.9.Decompose with water, release hydrogen, form calcium hydroxide; Calcium salts are formed when hydrogen is released from acid decomposition. Exposure to damp air causes slow decomposition. It has reducibility and can reduce many metal oxides above 500℃. It can burn in the air. Preparation of calcium hydride: in the temperature of 100 ~ 400℃, through the direct reaction of calcium and hydrogen, or in the presence of sodium, by dry calcium chloride and hydrogen reaction.
Calcium hydride is an alkali earth hydride. This grey powder (white if pure, which is rare) reacts violently with water to release hydrogen gas. Therefore, CaH2 is used as a desiccant or desiccant
CaH2 is a brine hydride, which means its structure is salt-like. Both the alkali metals and the alkali earth metals are heavier than beryllium from saline hydrides. A famous example is sodium hydride, which crystallizes in the NaCl motif. These substances are insoluble in all solvents with which they do not react.CaH2 crystallized in the structure of PbCl2(cobalt ore). 
Grignard method for calcium hydride
Geer Geyangh, a Russian chemist in the 18th century, invented a method of making calcium hydride. Geer Geyangh, a Russian chemist in the 18th century, invented a method of making calcium hydride. The reaction material of this method is easy to obtain. Calcium hydride can be made by reacting calcium oxide with hydrogen gas and separating water continuously. However, due to the excessive reaction temperature, this reaction is easy to generate by-products (a large amount of Ca(OH)2), and the conversion rate is too low (about 5%).In the 19th century, after the industry through the electrolytic method of calcium, calcium and hydrogen reaction is generally used to prepare calcium hydride method, the Grignard method was quickly eliminated.
Conditions for the reaction of calcium hydride by the Grignard method:
At atmospheric pressure, 820℃-830℃, using silica powder as a catalyst can slightly accelerate the reaction rate (10%), the effect is not obvious. Under normal conditions, this reaction is difficult to carry out. Therefore, in order to produce calcium hydride, the water vapor must be separated continuously and the reaction must move forward to produce calcium hydride. The separation method is: the use of hydrogen and water vapor density is different, continue to use a pump to pump up the gas. However, because hydrogen and water vapor can not be completely separated, part of hydrogen will be removed during pumping, resulting in hydrogen waste, which is also the reason for the low yield of this reaction.
Application of calcium hydride
Calcium hydride can be used as a reducing agent, desiccant, and in hydrogen production and organic synthesis. Calcium hydride is a colorless rhombic crystal. Industrial product is gray, orthogonality or powder.Sensitive to moisture. It does not react with dry air, nitrogen and chlorine at normal temperature, but it can react with the above gases at high temperature to generate calcium oxide, calcium carbide and calcium chloride respectively. Hydrogen is released when it is decomposed with water, and can also react with ethanol to form hydrogen and ethanol-calcium. The reduction of metal oxides is stronger than sodium hydride or lithium hydride.
Calcium hydride can be used to produce ultrafine zirconium powder. Zirconia powder, calcium hydride, calcium oxide and magnesium oxide are mixed in a certain proportion. After heating reduction, a zirconia powder mixture can be obtained. The obtained powder was added to hydrochloric acid to form a soluble chloride salt, which was filtered to obtain zirconium metal powder. When zirconium powder is produced in this way, calcium oxide and zirconium metal powder gather together during reduction, which can play a passivation effect on the surface and increase the operational safety of the reduction product.
Calcium Hydride Catalysts for Olefin Hydrofunctionalization: Ring‐Size Effect of Macrocyclic Ligands on Activity
Calcium dihydride [CaH2]n forms an ionic lattice with calcium ions of coordination number nine (PbCl2‐type, ΔH(lattice)=2410 kJ mol−1).1 Heating in a vacuum activates its surface so that ethylene is hydrogenated using dihydrogen possibly by cationic calcium sites at the surface.2 Since the isolation of the first molecular calcium hydride complex [(BDI)Ca(thf)2(μ‐H)]2 (A; BDI=CH[C(CH3)NDipp]2, Dipp=2,6‐diisopropylphenyl), molecular calcium hydrides containing a variety of ancillary ligands3 have shown activity in olefin hydrogenation and in a number of related catalytic reactions, previously thought to be reserved for transition metal and lanthanide complexes (Figure 1).4 It can be assumed that the combination of electrophilic calcium center with a nucleophilic hydride ligand enables these catalytic reactions. In addition to colloidal [CaH2]n, calcium hydride clusters have been reported to catalyze olefin hydrogenation5 and a variety of hydride clusters of up to ten calcium atoms have been isolated.6 As an example of a mononuclear calcium hydride with a terminal Ca−H bond, [(TpAd,iPr)Ca(H)(thp)] (TpAd,iPr=hydrotris(3‐adamantyl‐5‐isopropyl‐pyrazolyl)borate) (B) has been reported more recently to catalyze olefin hydrogenation.3f Such reactive mononuclear calcium hydrides can generally be conceived as the active species in catalytic reactions involving olefinic substrates.
Compared to transition‐metal and lanthanide‐based systems, alkaline earth metal catalysts for hydrofunctionalization are still underdeveloped and understanding structure-activity/selectivity relationships in these systems appears crucial for their improvement. Previously we have introduced the NNNN macrocycle Me4TACD (Me4TACD=1,4,7,10‐tetramethyl‐1,4,7,10‐tetraazacyclododecane) derived from the twelve‐membered cyclen to support [CaH]+ as dinuclear hydride cations [(Me4TACD)2Ca2(μ‐H)2(thf)][BAr4]2 (C, Ar=C6H3‐3,5‐Me2) and shown their reactivity toward inactivated olefins.7b, 7c Evidently, this macrocycle is capable of kinetically stabilizing highly electrophilic fragments such as [CaH]+, although the mononuclear species [(Me4TACD)CaH(thf)x]+ remains elusive. We show here how the ring size of the supporting macrocycle affects the catalytic activity of the catalyst. The fifteen‐membered NNNNN ligand Me5PACP (Me5PACP=1,4,7,10,13‐pentamethyl‐1,4,7,10,13‐pentaazacyclopentadecane) supports [CaH]+ and precludes the coordination of THF at the cationic calcium center. The resulting hydride cation, isolated as a dimer [(Me5PACP)2Ca2(μ‐H)2]2+, catalyzed the H/D isotopic exchange as well as olefin hydrogenation and hydrosilylation significantly more efficiently than [(Me4TACD)2Ca2(μ‐H)2(thf)x]2+ due to easier dissociation into the monomer in solution.
Calcium Hydride Supplier
TRUNNANO (aka. Luoyang Tongrun Nano Technology Co. Ltd.) is a trusted global chemical material supplier & manufacturer with over 12 years' experience in providing super high-quality chemicals and Nanomaterials. Currently, our company has successfully developed a series of materials. The calcium hydride produced by our company has high purity, fine particle size and impurity content. For the latest price of calcium hydride, send us an email or click on the needed products to send an inquiry.
The chemical formula for calcium hydride is CaH2.Molecular weight 42.1.White rhombic crystal. The melting point is 816℃(in a hydrogen stream), decomposition is about 600℃, and the relative density is 1.9.Decompose with water, release hydrogen, form calcium hydroxide; Calcium salts are formed when hydrogen is released from acid decomposition. Exposure to damp air causes slow decomposition. It has reducibility and can reduce many metal oxides above 500℃. It can burn in the air. Preparation of calcium hydride: in the temperature of 100 ~ 400℃, through the direct reaction of calcium and hydrogen, or in the presence of sodium, by dry calcium chloride and hydrogen reaction.
Calcium hydride is an alkali earth hydride. This grey powder (white if pure, which is rare) reacts violently with water to release hydrogen gas. Therefore, CaH2 is used as a desiccant or desiccant
CaH2 is a brine hydride, which means its structure is salt-like. Both the alkali metals and the alkali earth metals are heavier than beryllium from saline hydrides. A famous example is sodium hydride, which crystallizes in the NaCl motif. These substances are insoluble in all solvents with which they do not react.CaH2 crystallized in the structure of PbCl2(cobalt ore).
Geer Geyangh, a Russian chemist in the 18th century, invented a method of making calcium hydride. Geer Geyangh, a Russian chemist in the 18th century, invented a method of making calcium hydride. The reaction material of this method is easy to obtain. Calcium hydride can be made by reacting calcium oxide with hydrogen gas and separating water continuously. However, due to the excessive reaction temperature, this reaction is easy to generate by-products (a large amount of Ca(OH)2), and the conversion rate is too low (about 5%).In the 19th century, after the industry through the electrolytic method of calcium, calcium and hydrogen reaction is generally used to prepare calcium hydride method, the Grignard method was quickly eliminated.
Conditions for the reaction of calcium hydride by the Grignard method:
At atmospheric pressure, 820℃-830℃, using silica powder as a catalyst can slightly accelerate the reaction rate (10%), the effect is not obvious. Under normal conditions, this reaction is difficult to carry out. Therefore, in order to produce calcium hydride, the water vapor must be separated continuously and the reaction must move forward to produce calcium hydride. The separation method is: the use of hydrogen and water vapor density is different, continue to use a pump to pump up the gas. However, because hydrogen and water vapor can not be completely separated, part of hydrogen will be removed during pumping, resulting in hydrogen waste, which is also the reason for the low yield of this reaction.
Application of calcium hydride
Calcium hydride can be used as a reducing agent, desiccant, and in hydrogen production and organic synthesis. Calcium hydride is a colorless rhombic crystal. Industrial product is gray, orthogonality or powder.Sensitive to moisture. It does not react with dry air, nitrogen and chlorine at normal temperature, but it can react with the above gases at high temperature to generate calcium oxide, calcium carbide and calcium chloride respectively. Hydrogen is released when it is decomposed with water, and can also react with ethanol to form hydrogen and ethanol-calcium. The reduction of metal oxides is stronger than sodium hydride or lithium hydride.
Calcium hydride can be used to produce ultrafine zirconium powder. Zirconia powder, calcium hydride, calcium oxide and magnesium oxide are mixed in a certain proportion. After heating reduction, a zirconia powder mixture can be obtained. The obtained powder was added to hydrochloric acid to form a soluble chloride salt, which was filtered to obtain zirconium metal powder. When zirconium powder is produced in this way, calcium oxide and zirconium metal powder gather together during reduction, which can play a passivation effect on the surface and increase the operational safety of the reduction product.
Calcium Hydride Catalysts for Olefin Hydrofunctionalization: Ring‐Size Effect of Macrocyclic Ligands on Activity
Calcium dihydride [CaH2]n forms an ionic lattice with calcium ions of coordination number nine (PbCl2‐type, ΔH(lattice)=2410 kJ mol−1).1 Heating in a vacuum activates its surface so that ethylene is hydrogenated using dihydrogen possibly by cationic calcium sites at the surface.2 Since the isolation of the first molecular calcium hydride complex [(BDI)Ca(thf)2(μ‐H)]2 (A; BDI=CH[C(CH3)NDipp]2, Dipp=2,6‐diisopropylphenyl), molecular calcium hydrides containing a variety of ancillary ligands3 have shown activity in olefin hydrogenation and in a number of related catalytic reactions, previously thought to be reserved for transition metal and lanthanide complexes (Figure 1).4 It can be assumed that the combination of electrophilic calcium center with a nucleophilic hydride ligand enables these catalytic reactions. In addition to colloidal [CaH2]n, calcium hydride clusters have been reported to catalyze olefin hydrogenation5 and a variety of hydride clusters of up to ten calcium atoms have been isolated.6 As an example of a mononuclear calcium hydride with a terminal Ca−H bond, [(TpAd,iPr)Ca(H)(thp)] (TpAd,iPr=hydrotris(3‐adamantyl‐5‐isopropyl‐pyrazolyl)borate) (B) has been reported more recently to catalyze olefin hydrogenation.3f Such reactive mononuclear calcium hydrides can generally be conceived as the active species in catalytic reactions involving olefinic substrates.
Calcium Hydride Supplier
TRUNNANO (aka. Luoyang Tongrun Nano Technology Co. Ltd.) is a trusted global chemical material supplier & manufacturer with over 12 years' experience in providing super high-quality chemicals and Nanomaterials. Currently, our company has successfully developed a series of materials. The calcium hydride produced by our company has high purity, fine particle size and impurity content. For the latest price of calcium hydride, send us an email or click on the needed products to send an inquiry.
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