Tyzor

The standard manufacturing method for tetraalkyl titanates, such as TYZOR TPT, or tetra- -butyi titanate, TYZOR TBT [5593-70 ] involves the addition of TiCl to an alcohol. In a series of reversible displacement reactions, the alkoxy substitution products and hydrochloric acid form as follows ... 

TYZOR TPT and the tetraethyl titanate, TYZOR ET [3087-36-3], have also been prepared by direct electrochemical synthesis. The reaction involves anode dissolution of titanium in the presence of the appropriate alcohol and a conductive admixture (3). 

Higher alkoxides, such as tetra(2-ethylhexyl) titanate, TYZOR TOT [1070-10-6], can be prepared by alcohol interchange (transestenfication) in a solvent, such as benzene or cyclohexane, to form a volatile a2eotrope with the displaced alcohol, or by a solvent-free process involving vacuum removal of the more volatile displaced alcohol. The affinity of an alcohol for titanium decreases in the order primary > secondary > tertiary, and... 

Phenols react readily with tetraalkoxides to give highly colored (yeUow to orange) titanium tetraphenoxides (6). TYZOR KTM [83897-99-8] is the bis-cresyl titanate derived from TYZOR TBT. The tetracresyl titanate [28503-70-0] is also available commercially. 

Fluoroall l-SubstitutedTitanates. Tetraliexafluoroisopropyl titanate [21416-30-8] can be prepared by the reaction of TiCl and hexafluoroisopropyl alcohol [920-66-17, in a process similar to that used for TYZOR TPT (7). Alternatively, it can be prepared by the reaction of sodium hexafluoroisopropoxide and TiCl ia excess hexafluoroisopropyl alcohol (8). The fluoroalkyl material is much more volatile than its hydrocarbon counterpart, TYZOR TPT, and is used to deposit titanium on surfaces by chemical vapor-phase deposition (CVD). 

Titanium Complexes of Unsaturated Alcohols. TetraaHyl titanate can be prepared by reaction of TYZOR TPT with aHyl alcohol, followed by removal of the by-product isopropyl alcohol. EbuUioscopic molecular weight determinations support its being the dimeric product, octaaHoxydititanium. A vinyloxy titanate derivative can be formed by reaction of TYZOR TPT with vinyl alcohol formed by enolization of acetaldehyde (11) ... 

Increased molecular association iacreases viscosity. Tetra-/-butyl titanate and tetraisopropyl titanate are mobile Hquids at room temperature tetra- -butyl titanate and tetra- -propyl titanate, TYZOR NPT [3087-37-4], are thick and sympy. The boiling poiats of these materials also reflect association (Table 1). 

Higher aUphatic alcohol and phenoHc group-containing polytitanates may be prepared by transesterification of TYZOR BTP (24). 

Thermolysis is used in the coating of glass and other surfaces with a film of titanium dioxide. When a lower alkoxide, eg, TYZOR TPT, vaporizes in a stream of dry air and is blown onto hot glass botdes above ca 500°C, a thin, transparent protective coating of Ti02 is deposited. 

Chelated titanates are made simply by mixing the chelating agent with TYZOR TPT or another alkoxide. The Hberated alcohol is usually left in the product to maintain the products fluidity. It may, however, be removed by distillation if desirable. Organic titanates are normally shipped in 208-L dmms, totes, cylinders, or tank tmcks. Most titanates are moisture-sensitive and must be handled with care, preferably under dry nitrogen. 

Reaction of 2,4-diorgano-l,3-diols, such as 2-ethylhexane-l,3-diol, with TYZOR TPT in a 2 1 molar ratio gives the solvent soluble titanate complex, TYZOR OGT [5575-43-9] (4) (73). If the reaction is conducted in an inert solvent, such as hexane, and the resultant slurry is treated with an excess of water, an oligomeric hydrolysis product, also solvent-soluble, is obtained (74). 

The reaction products of TYZOR TPT with 2—4 moles of 1,3-diols having two to three alkyl substituents, such as 2,2,4-trimethyl-l,3-pentanediol, gives complexes that could be used as cross-linking agents for hydroxy group containing powdered lacquer resins (76). 

TYZOR LA [65104-06-5] (5), an aqueous solution of the ammonium salt of the titanium bis-lactate complex, is prepared from two equivalents of lactic acid to one of TYZOR TPT. The by-product isopropyl alcohol is removed by distillation and the resultant solution is neutralized with ammonium hydroxide. 

P-Diketone Chelates. P-Diketones, reacting as enols, readily form chelates with titanium alkoxides, Hberating in the process one mole of an alcohol. TYZOR AA [17927-72-9] (6) is the product mixture from TYZOR TPT and two moles of acetylacetone (acac) reacting in the enol form. The isopropyl alcohol is left in the product (87). The dotted bonds of stmcture (6) indicate electron... 

The addition of TYZOR AA to larger quantities of water results in precipitation of the polytitanaoxane as a yellow soHd, which can be isolated and dried (92). The precipitation of this soHd can be prevented by diluting the TYZOR AA with an equal volume of 10% aqueous acetic acid and then 13 times the amount of a 1 1 mixture of isopropyl alcohol and water (93). 

The TYZOR AA, which is a 75% isopropyl alcohol solution, is unstable in cold storage. The titanate complex precipitates from solution and causes handling difficulties. The addition of small amounts (0.05—0.15 mol water/mol titanate) of water gives a solution, TYZOR AA75, that is stable in cold-temperature storage (95). 

The solvent-free mono- -butyl, monoisopropyl bis-acetylacetone titanate, TYZOR AA95 [9728-09-9] is a Hquid at room temperature. By carefully controlling the mixture of alcohols used as solvent, a product, TYZOR GBA can be obtained, which is cold-storage-stable even in the presence of nucleating agents (96). 

P-Ketoester Chelates. p-Ketoesters react in a fashion similar to the p-diketones. TYZOR DC [27858-32-8] is the hght-yeUow Hquid from TYZOR TPT and two moles of ethyl acetoacetate (eaa) after removal of the isopropyl alcohol. TYZOR BEAT, the bis-ethylacetoacetate [20753-28-0] derived from the tetra- -butyl titanate, and TYZOR IBAY [83877-91-2] the isobutoxy analogue, perform similarly to TYZOR DC. Both, however, have better cold-storage stabiHty. 

Partial hydrolysis of TYZOR DC or the monoethylacetoacetate ester chelate, followed by removal of the isopropyl alcohol by-product, gives a dimeric )J.-oxo chelate (8), which also has improved cold-temperature-storage stabiUty (98). 

Reaction of TYZOR DC and 1,3-propanediol gives titanium 1,3-propylenedioxide bis(ethyl acetoacetate) [36497-11-7J, which can be used as a noncorrosive curing catalyst for room-temperature-vulcanizing siUcone mbber compositions (99). Similar stmctures could be made, starting with titanium bis-acetylacetonates, such as that shown in stmcture (9). 

The 1-alkoxytitatranes can be synthesized by the reaction of equimolar amounts of tetraalkyl titanates and triethanolamine (105). X-ray crystallographic analysis of the soHd isolated from the reaction of one mole of triethanolamine and one mole of TYZOR TPT confirms the stmcture as a centrosymmetric dimer having a Ti isopropoxy nitrilotriethoxy ratio of 1 1 1. The titanium atoms have achieved a coordination number of six via a rather unsymmetrical titanium—oxygen bridge (106). 

Products from aminoalcohols and TYZOR TPT were obtained by a2eotropiag the isopropyl alcohol with ben2ene (121,122). From trimethylethylenediamine, dimethylethanolamine, and dimethylisopropanolamine with TYZOR TPT, the orange (11), the yellow (12), and the pale-green (13) were obtained, respectively. The lithium salt of the ligand, derived from C H Li, combiaed with (RO)2TiCl ia hexane has also been used (123). 

The ratio of yy -epoxide (shown above) to ant -eipoxide is 10—25 1 with TYZORTPT catalysis, whereas vanadjdacetylacetonate is less selective and y -chloroperoxybenzoic acid gives the reverse 1 25 ratio. It is supposed that TYZOR TPT esterifies the free hydroxyl, then coordinates with the peroxide to favor yy -epoxidation (135). This procedure is related to that for enantioselective epoxidation of other allyflc alcohols in 9—95% enantiomeric excess (135). 

Reaction of TYZOR TPT with polyperfluoroalkylene ethers containing a carbonyl group produces a complex that is an excellent surface-treating agent, imparting improved surface wettabiUty and anticorrosion properties to metal surfaces (144). These complexes can be used by themselves, or as additives to perfluoropolyethers as vacuum pump oils, lubricant oils, or mold release agents. 

Other Complexes. The reaction of TYZOR TPT with two equivalents of a semicarba2one produces complex (17), the stmcture of which has been assigned the trans-configuration (148) ... 

Barium titanate thin films can be deposited on various substances by treating with an aqueous solution containing barium salts and an alkanolamine-modifted titanate such as TYZOR TE (151). In a similar fashion, reaction of a tetraalkyl titanate with an alkah metal hydroxide, such as potassium hydroxide, gives oxyalkoxide derivatives (KTi O(OR) ), which can be further processed to give alkali metal titanate powders, films, and fibers (152—155). The fibers can be used as adsorbents for radioactive metals such as cesium, strontium, and uranium (156). 

Addition of lithium or sodium alkoxide to TYZOR TPT gives a double alkoxide derivative, MTi2(OR), the stmcture of which has been proposed (157) as follows, where M = Na or Li. 

Titanium—Vanadium Mixed Metal Alkoxides. Titanium—vanadium mixed metal alkoxides, VO(OTi(OR)2)2, are prepared by reaction of titanates, eg, TYZOR TBT, with vanadium acetate ia a high boiling hydrocarbon solvent. The by-product butyl acetate is distilled off to yield a product useful as a catalyst for polymeri2iag olefins, dienes, styrenics, vinyl chloride, acrylate esters, and epoxides (159,160). 

Polytitanosiloxane (PTS) polymers containing Si—O—Ti linkages have also been synthesized through hydrolysis—polycondensation or hydrolysis—polycondensation—pyrolysis reactions involving clear precursor sol solutions consisting of monomeric silanes, TYZOR TET, methanol, water, and hydrochloric acid (Fig. 2). These PTS polymers could be used to form excellent corrosion protection coatings on aluminum substrates (171). 

TYZOR ET is reduced by sodium and ethanol to a dark-blue compound (182). Use of potassium as the reducing agent in the alcohol permits the isolation and identification of Ti(OC2H2)3 [22922-82-3] and Ti(OC4Hg)3 [5058-41-3] (183,184). The products precipitate as soUd alcoholates,... 

The addition of an alkanolamine, such as diethanolamine, to TYZOR TBT, as well as the use of a less moisture-sensitive alkanolamine titanate complex such as TYZOR TE, has been reported to prolong catalyst life and minimi2e ha2e formation in the polymer (475—476). Several excellent papers are available that discuss the kinetics and mechanism of titanate-cataly2ed esterification and polycondensation reactions (477—484). 

MetlylEsters. The addition product of two moles of TYZOR TPT and one mole of ethylene glycol, GLY—TI, can be used as a transesterification catalyst for the preparation of methyl esters. The low solubility of tetramethyl titanate has prevented the use of them as a catalyst for methyl ester preparation (488). 

Epoxy cross-linking is cataly2ed by TYZOR TPT and TYZOR TBT, alone or with piperidine, and by TYZOR TE. The soHd condensation product from 3 TPT 4 TEA (triethanolamine) has also been appHed to epoxy curing (490). Titanate curing is accelerated by selected phenoHc ethers and esters at 150°C the mixtures have along pot life at 50°C (491) (see Epoxyresins). 

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