Zirconium amines

The activity of 36 200 kg mol h (Table 15.1) is comparable to the extremely high activities reported for zirconium amine-bis(phenoxide) complexes [20]. Upon reducing the polymerization temperature to -30 "C, the activity dropped to 2030 kg mol h" however, at this temperature the poly(l-hexene) produced... 

Catalysts used for preparing amines from alcohols iaclude cobalt promoted with tirconium, lanthanum, cerium, or uranium (52) the metals and oxides of nickel, cobalt, and/or copper (53,54,56,60,61) metal oxides of antimony, tin, and manganese on alumina support (55) copper, nickel, and a metal belonging to the platinum group 8—10 (57) copper formate (58) nickel promoted with chromium and/or iron on alumina support (53,59) and cobalt, copper, and either iron, 2iac, or zirconium (62). 

High molecular weight primary, secondary, and tertiary amines can be employed as extractants for zirconium and hafnium in hydrochloric acid (49—51). With similar aqueous-phase conditions, the selectivity is in the order tertiary > secondary > primary amines. The addition of small amounts of nitric acid increases the separation of zirconium and hafnium but decreases the zirconium yield. Good extraction of zirconium and hafnium from ca 1 Af sulfuric acid has been effected with tertiary amines (52—54), with separation factors of 10 or more. A system of this type, using trioctylarnine in kerosene as the organic solvent, is used by Nippon Mining of Japan in the production of zirconium (55). 

Zirconium tetrachloride is instantly hydrolyzed in water to zirconium oxide dichloride octahydrate [13520-92-8]. Zirconium tetrachloride exchanges chlorine for 0x0 bonds in the reaction with hydroxylic ligands, forming alkoxides from alcohols (see Alkoxides, METAl). Zirconium tetrachloride combines with many Lewis bases such as dimethyl sulfoxide, phosphoms oxychloride and amines including ammonia, ethers, and ketones. The zirconium organometalLic compounds ate all derived from zirconium tetrachloride. 

The extraction of metals by liquid amines has been widely investigated and depends on the formation of anionic complexes of the metals in aqueous solution. Such applications are illustrated by the use of Amberlite LA.l for extraction of zirconium and hafnium from hydrochloric acid solutions, and the use of liquid amines for extraction of uranium from sulphuric acid solutions.42,43... 

In 1992, Bergman et al. reported that zirconium bisamides Cp2Zr(NHR)2 catalyze the intermolecular hydroamination of alkynes with sterically hindered primary amines to give enamines or their tautomeric imines (e.g., Eq. 4.77) [126]. 

Complexes of tetravalent zirconium with organic acids, such as citric, tartaric, malic, and lactic acids, and a complex of aluminum and citric acid have been claimed to be active as dispersants. The dispersant is especially useful in dispersing bentonite suspensions [288]. Polymers with amine sulfide terminal moieties are synthesized by using aminethiols as chain transfer agents in aqueous addition polymerizations. The polymers are useful as mineral dispersants [1182]. 

Boron zirconimn chelates from ammonium hydroxide water-soluble amines sodium or potassimn zirconium and organic acid salts such as lactates, citrates, tartrates, glycolates, malates, gluconates, glycerates, and mandelates with polyols such as glycerol, erythritol, arabitol, xylitol, sorbitol, dulcitol, mannitol, inositol, monosaccharides, and disaccharides [463,464,1592,1593]... 

Other examples of this synthetic strategy are known for example, a recent zirconium polymer by Illingsworth and Burke (8), who joined amine side groups of a zirconium bis(quadridentate Schiff-base) with an acid dianhydride to give amide linkages. Once again, caution is necesary, as Jones and Power (2) learned when they attempted to link metal bisO-diketonates) with sulfur halides that is, they obtained insoluble metal sulfides because the p-diketone complexes which they used were fairly labile and the insolubility drove the reactions to completion in the wrong direction. 

Yang XB, Fu X-K, Zeng R-Q (2010) Intercalation of non-aromatic heterocyclic amines into layered zirconium glycine-N, N-dimethylphosphonate. Chem Paper 64( 1) 118-122... 

Recently, the oxidation of primary aliphatic amines to the corresponding nitro compounds has also been achieved using the catalyst system based on zirconium tetra tert-butoxide and tert-butyl hydroperoxide in a molecular sieve (50-98% yield) (Eqs. 2.56 and 2.57 and Table... 

The amination of styrene, however, led to two products (1-phenyl-1-ethylamine and 2-phenyl-l-ethylamine) in a 1 3 ratio [113], indicating that the hydrozirconation was not completely regioselective [114,115]. Since it is well known that hydrozirconation of trisubsti-tuted alkenes places zirconium at the least hindered carbon of the chain by a process involving zirconium migration, this class of alkenes was not investigated [5,116], On the other hand, hydrozirconation/amination of 3-methyl-l,2-butadiene gave an allylic amine. Reaction of the latter could either occur at the terminal carbon or proceed with... 

Aryl chlorothioformates, 23 628 Aryl complexes, zirconium, 26 655 Aryl ethers, uses for, 70 581 2-Arylglycine esters, 72 166 Aryl halide amination, 9 278 Aryl halides, reaction with carbon monoxide, 5 11 Arylhydrazines, 9 270 Arylmethane dyes, 9 503... 

Aminoborollide complexes of zirconium and hafnium that incorporate both Lewis acid and Lewis base sites have been explored.1 a In molecules such as 9, the amine nitrogen carries an electron lone pair while the d° metal center is acidic ... 

Given the importance of chiral amines to synthetic chemistry as well as other fields asymmetric hydrogenation of imines has attracted wide interest but limited success compared to C=C and C=0 bond reduction. The first asymmetric hydrogenation of imines was carried out in the seventies with mthenium- and rhodium-based catalysts, followed later by titanium and zirconium systems [82]. Buchwald found that... 

Preequilibration of the solvent may be required. In some systems, this cost is minimal, but in others it may be high for example, in uranium extraction from sulfate solutions using tertiary amines, the sulfuric acid preequilibration of the solvent before extraction is a few cents or less per pound of UsOg produced. By comparison, in a TBP-HNO3 system for the recovery of zirconium, the preequilibration costs, using nitric acid, amount to about 50 cents per pound of Zr produced. 

A recent method reported for the oxidation of primary aliphatic amines to nitro compounds uses fert-butylhydroperoxide (TBHP) and catalytic zirconium tetra-fert-butoxide in presence of molecular sieves. 

Representative metal complexes employed for the catalytic asymmetric Strecker reaction are summarized in Figure 4.2. Aluminum-, titanium-, lanthanoid-, and zirconium-based catalysts are highly efficient. Direct one-pot synthesis starting from aldehydes, and amines is reported using the Zr complex described in Figure 4.2. ... 

Zirconium(IV) and hafnium(IV) halides form adducts with a variety of monodentate and polydentate amines. Typical complexes are listed in Table 3. In general, these compounds are air- and moisture-sensitive white solids (yellow when the halide is iodide), thermally stable and insoluble in most organic solvents. 

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