Zirconium propionate

In the case of organic derivatives such as zirconium acetate, direct bonding of the carboxyiate to the zirconium is found. Similar structures are also found in solvent-soluble, water-insoluble carboxylates such as zirconium propionate. Zirconium alkoxide derivatives tend to be monomeric in solvent-based systems but hydrolyse rapidly with ambient water to give polymeric species. 

Zirconium propionate is a polymeric zirconium carboxylate its structure is illustrated in Fig. 10. Use of zirconium propionate markedly increases the adhesion of an ink applied to treated polypropylene film. Figure 11 compares zirconium propionate with titanium acetylacetonate, which is commonly regarded as the industry standard. The standard test method used in the ink industry is the so-called tape test . Sticky tape is placed on the printed film and pressure is applied by the operator s thumb. The tape is then pulled off, by hand, and the amount of ink removed is visually assessed. Although extremely crude, it can be, and is, used for control in the ink industry. 

Further work by Comyn (private communication) has attempted to use a peel test to measure the actual adhesion improvements. Zirconium propionate was... 

Figure 11. Comparison between zirconium propionate and titanium acetylacetonate as adhesion promoters in a simple ink formulation.

Zirconium propionate Zircoaluminates Zirconium acetylacetonate, zirconium methacrylate... 

Propanoic acid, zirconium salt. See Zirconium propionate... 

Zirconium carbonate basic zirconium oxide precursor, hydrolyzable Zirconium propionate zirconium oxide source Zirconium silicate zirconium source, metallic Zirconium silicate... 

C3H6O2 %Zr Zirconium propionate C3H6O2 ViMg Magnesium propionate C3H6O2 H3N Ammonium propionate C3H6O2S... 

Zirconate coupling agents have a stracture very similar to that of titanates. Zirconium propionate is used as an adhesion promoter in printing ink formulations for polyolefins. Like the titanates, zirconate coupling agents are useful in improving the dispersion characteristics of fillers in polymer systems. 

To conclude this discussion on zirconium, it is appropriate to look at the adhesion promotion effects of various zirconium compounds in flexographic and gravure ink printed on corona discharge-treated polyolefins and polyester. Flexographic and gravure inks are basically a pigment (often titanium dioxide) suspended in a polymer (normally called the binder) dissolved in a solvent. Actual commercial ink formulations are rather more complicated. These inks are either water-based when acrylic polymers and co-polymers are typically the binders, or solvent-based (usually ethanol-ethyl acetate mixtures) when the binder is typically nitrocellulose or cellulose acetate propionate. 

In 1997, the first truly catalytic enantioselective Mannich reactions of imines with silicon enolates using a novel zirconium catalyst was reported [9, 10]. To solve the above problems, various metal salts were first screened in achiral reactions of imines with silylated nucleophiles, and then, a chiral Lewis acid based on Zr(IV) was designed. On the other hand, as for the problem of the conformation of the imine-Lewis acid complex, utilization of a bidentate chelation was planned imines prepared from 2-aminophenol were used [(Eq. (1)]. This moiety was readily removed after reactions under oxidative conditions. Imines derived from heterocyclic aldehydes worked well in this reaction, and good to high yields and enantiomeric excesses were attained. As for aliphatic aldehydes, similarly high levels of enantiomeric excesses were also obtained by using the imines prepared from the aldehydes and 2-amino-3-methylphenol. The present Mannich reactions were applied to the synthesis of chiral (3-amino alcohols from a-alkoxy enolates and imines [11], and anti-cc-methyl-p-amino acid derivatives from propionate enolates and imines [12] via diastereo- and enantioselective processes [(Eq. (2)]. Moreover, this catalyst system can be utilized in Mannich reactions using hydrazone derivatives [13] [(Eq. (3)] as well as the aza-Diels-Alder reaction [14-16], Strecker reaction [17-19], allylation of imines [20], etc. 

Kobayashi S, Ishitani H (2000) Novel binuclear chiral zirconium catalysts used in enantioselective strecker reactions. Chirality 12 540-543 Kobayashi S, Ishitani H, Nagayama S (1995) Synthesis 1995 1195 Kobayashi S, Ishitani H, Ueno M (1998) J Am Chem Soc 120 431 Kobayashi S, Kobayashi J, Ishitani H, Ueno M (2002) Catalytic enantioselective addition of propionate units to imines an efficient synthesis of anti-alpha-methyl-beta-amino acid derivatives. Chem Eur J 8 4185 1190 Krohn K, Kirst HA, Maag H (eds) (1993) Antibiotics and antiviral compounds. VCH, Weinheim... 

A unique approach to the stereochemical complexities of erythronolide A was developed by Deslongchamps as outlined in Scheme 2,19. The methyl ester of erythronolide A seco acid (212) was dehydrated to form the cyclic ketal 213. A multistep oxidation of the side chain then gave aldehyde 214 which, when condensed with the zirconium enolate of methyl propionate, afforded a 10 1 ratio of aldol diastereomers, the major being 213. Furthermore, aldehyde 214 could easily be converted into the y-lactone 215. 

Anhydrous acetic arid not containing formic arid is collected at the base of the dehydrator. This stream is then rid of the heavy compounds (propionic arid) and concentrated to 99.8 per cent weight by distillation (about 30 trays). Corrosion is limited by building some parts of the installation of copper, titanium or zirconium. 

The high syn stereoselectivity attained in zirconium enolate aldol reactions has proved useful in complex natural product synthesis. The zirconium-mediated aldol reaction of the chiral ethyl ketone (9) with a chiral aldehyde has been used by Masamune et al. to give selectively adduct (10), which was further elaborated into the ansa chain of rifamycin S (equation 1). Good enolate diastereofacial selectivity is also obtained here and leads to a predominance of one of the two possible syn adducts. A zirconium enolate aldol reaction also features in the Deslongchamps formal total synthesis of erythromycin A, where the di(cyclopentadienyl)chiorozirconium enolate from methyl propionate adds with high levels of Cram selectivity to the chiral aldehyde (11) to give the syn adduct (12 equation 2). A further example is... 

Not all aldol additions exhibit a dependence of product configuration on enolate geometry. Acid catalyzed aldols [45], some base catalyzed aldols [58], and aldols of some transition metal enolates [63,64] show no such dependency. For example, zirconium enolates afford syn adducts ( / topicity) independent of enolate geometry for a number of propionates [63,64]. As shown in Scheme 5.9, two explanations have been proposed to explain the behavior of zirconium enolates. One explanation (Scheme 5.9a) is that the closed transition structure changes from a chair for the Z(0)-enolate to a boat for the (0)-enolate [16,63,65]. Another hypothesis is that these additions occur via an open transition structure. Although the original authors... 

The in situ construction of the inorganic component within a cast polymer solution is not limited to metal oxides and in practice a range of other inorganic materials can be formed depending on the choice of precursor(s) incorporated in the polymer solution, and the nature of post-treatment following solvent removal. Roziere and Jones and co-workers have developed nano composite membranes in which zirconium phosphate is formed from zirconyl propionate introduced into a DMAc solution of sPEEK, by immersion of the cast film, after solvent removal, into phosphoric acid. This approach provides a robust synthetic route that can be generalised to other ionomers, and allows the amount of ZrP to be readily varied, even up to ca. 40-50 wt. %. 

Phenyl acetate p-Quinone dioxime Toluene-2,4-diamine Tributyl phosphine 1,1,3-Triethoxy-3-methoxypropane Triethylene diamine Triethylenemelamine Trimethylolpropane tris-(B-(N-aziridinyl) propionate) Tris [1-(2-methyl-aziridinyl) phosphine oxide] Zinc acetylacetonate Zirconium acetate crosslinking agent, castings PEG-4 dimethacrylate crosslinking agent, coatings PEG-4 dimethacrylate... 

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