Hydrogenation copper metal

Hydrazine Alkali metals, ammonia, chlorine, chromates and dichromates, copper salts, fluorine, hydrogen peroxide, metallic oxides, nickel, nitric acid, liquid oxygen, zinc diethyl... 

Silane reacts with methanol at room temperature to produce methoxymonosilanes such as Si(OCH2)4 [78-10-4] HSi(OCH2)3, and H2Si(OCH3)2 [5314-52-3] but not H SiOCH [2171 -96-2] (23). The reaction is catalyzed by copper metal. In the presence of alkoxide ions, SiH reacts with various alcohols, except CH OH, to produce tetraalkoxysHanes and hydrogen (24). 

Cupric chloride or copper(II) chloride [7447-39 ], CUCI2, is usually prepared by dehydration of the dihydrate at 120°C. The anhydrous product is a dehquescent, monoclinic yellow crystal that forms the blue-green orthohombic, bipyramidal dihydrate in moist air. Both products are available commercially. The dihydrate can be prepared by reaction of copper carbonate, hydroxide, or oxide and hydrochloric acid followed by crystallization. The commercial preparation uses a tower packed with copper. An aqueous solution of copper(II) chloride is circulated through the tower and chlorine gas is sparged into the bottom of the tower to effect oxidation of the copper metal. Hydrochloric acid or hydrogen chloride is used to prevent hydrolysis of the copper(II) (11,12). Copper(II) chloride is very soluble in water and soluble in methanol, ethanol, and acetone. 

Steam reforming is the reaction of steam with hydrocarbons to make town gas or hydrogen. The first stage is at 700 to 830°C (1,292 to 1,532°F) and 15-40 atm (221 to 588 psih A representative catalyst composition contains 13 percent Ni supported on Ot-alumina with 0.3 percent potassium oxide to minimize carbon formation. The catalyst is poisoned by sulfur. A subsequent shift reaction converts CO to CO9 and more H2, at 190 to 260°C (374 to 500°F) with copper metal on a support of zinc oxide which protects the catalyst from poisoning by traces of sulfur. 

The platinum metals are valuable by-products from the extraction of common metals such as copper and nickel. The anodic residue that results from copper refining is a particularly important source. The chemistry involved in their purification is too complicated to describe here, except to note that the final reduction step involves reaction of molecular hydrogen with metal halide complexes. 

The reaction between hydrogen and an aquatic medium holding say a copper metal ion, Cu2+, can be shown as ... 

Considerable practical importance attaches to the fact that the data in Table 6.11 refer to electrode potentials which are thermodynamically reversible. There are electrode processes which are highly irreversible so that the order of ionic displacement indicated by the electromotive series becomes distorted. One condition under which this situation arises is when the dissolving metal passes into the solution as a complex anion, which dissociates to a very small extent and maintains a very low concentration of metallic cations in the solution. This mechanism explains why copper metal dissolves in potassium cyanide solution with the evolution of hydrogen. The copper in the solution is present almost entirely as cuprocyanide anions [Cu(CN)4]3, the dissociation of which by the process... 

Copper metal surface area was determined by nitrous oxide decomposition. A sample of catalyst (0.2 g) was reduced by heating to 563 K under a flow of 10 % H2/N2 (50 cm min"1) at a heating rate of 3 deg.min 1. The catalyst was then held at this temperature for 1 h before the gas flow was switched to helium. After 0.5 h the catalyst was cooled in to 333 K and a flow of 5 %N20/He (50 cm3mirr ) passed over the sample for 0.25 h to surface oxidise the copper. At the end of this period the flow was switched to 10 % H2/N2 (50 entitlin 1) and the sample heated at a heating rate of 3 deg.min"1. The hydrogen up-take was quantified, from this a... 

Hydrazinium nitrate Alone, or Metals Hydrogen sulfide Metals Potassium dioxide Metals Sulfuric acid Copper... 

KLP [Dow K Catalyst liquid phase] A selective hydrogenation process for removing acetylenes from cmde C4 hydrocarbons from ethylene cracking, with no loss of butadiene. The catalyst is based on either copper metal or alumina. Developed by Dow Chemical Company and first commercialized at its plant in Temeuzen, The Netherlands. The KLP licensing business was sold to UOP in 1991. 

By contrast, copper metal does not react with water to liberate hydrogen in a reaction like Equation (7.35) on the contrary, black copper(II) oxide reacts with hydrogen gas to form copper metal ... 

If a piece of copper metal was placed in a solution of SrfNOj aq) there would be no reaction, since copper is lower than tin on the activity series. This table allows us to also predict that if sodium metal is placed in water, it will displace hydrogen, forming hydrogen gas ... 

Worked Example 5.2. During the reductive formation of copper metal (from an aqueous solution of Cu " ), it is noticed that hydrogen gas is formed at the negative cathode, that is, in addition to the formation of a layer of fresh, pink copper metal. The volume of the gas at STP is 2.24 dm, and the overall electrochemical charge passed was 1.40 x 10 C. What is the electrolytic efficiency ... 

Strategy. We will need to decide first (i) the identity and stoichiometry of the second electrode reaction. Then, we will work out (ii) how much of the charge was required to form the hydrogen by this route. Therefore, knowing the overall charge and the amount consumed in the side reaction, (iii) we can work out the faradaic fraction utilized to form copper metal. 

The metal is not strong enough to reduce H+ from acids to H2. Therefore, under ordinary conditions, copper metal does not liberate hydrogen from mineral acids. Copper can reduce Ag" ", Au6+, and Hg + ions that have greater positive E° values for reduction half reactions, thus displacing these metals from their aqueous solutions. 

Use the information in Appendix 2A to determine the standard reaction enthalpies of (a) the oxidation of 10.0 g of sulfur dioxide to sulfur trioxide (b) the reduction of 1.00 mol CuO(s) with hydrogen to give copper metal and liquid water. 

When solid copper(II) oxide and hydrogen react, metallic copper and water form. 

Reduction of cupric acetate An unreduced solution of cupric acetate in quinoline is a dark green color the fully reduced solution is a clear ruby red. When quinone has been reduced, as described above, further treatment with hydrogen produces metallic copper. In contrast, when cupric ion has all been reduced to cuprous ion, no further reduction occurs within convenient experimental times, and the solution remains clear. The reduced cupric solution can be reoxidized rapidly by oxygen at room temperature. 

As reported elsewhere, the experiments were used to demonstrate the major process steps with recycle of the uranium. Most experiments were conducted in an alumina-lined tube furnace with the uranium in an alumina boat. Hydrogen gases were produced and measured. Reduction of CuO to copper metal, determined by weight loss, was the primary method used to measure the amount of reductant produced. X-ray diffraction analysis was used in most cases to confirm the uranium species. 

Reactions of methane and ethane with HF recyclable metal fluorides to give fluorocarbons have been reported briefly in the patent and journal literature [16-18], Reaction of methane with hydrogen fluoride in the presence of oxygen and the salt or oxide of a variable valency metal as catalyst yielded small amounts of fluoromethane and difluoromethane at temperatures above 500°C. Olsen et al. [17] reacted copper(ll) fluoride with methane at high temperatures (>600°C) and found products that always included copper metal, hydrogen fluoride, fluoromethane and carbon. Although activity was first detected around... 

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