Esters Dibutyltin oxide

Polyhydric alcohol mercaptoalkanoate esters are prepared by reaction of the appropriate alcohols and thioester using -toluenesulfonic acid catalyst under nitrogen and subsequent heating (16,17). Organotin mercapto esters are similarly produced by reaction of the esters with dibutyltin oxide (18). Pentaerythritol can be oxidized to 2,2-bis(hydroxymethyl)hydracryhc acid [2831-90-5] C H qO, ... 

Chemical Properties. Trimethylpentanediol, with a primary and a secondary hydroxyl group, enters into reactions characteristic of other glycols. It reacts readily with various carboxyUc acids and diacids to form esters, diesters, and polyesters (40). Some organometaUic catalysts have proven satisfactory for these reactions, the most versatile being dibutyltin oxide. Several weak bases such as triethanolamine, potassium acetate, lithium acetate, and borax are effective as stabilizers for the glycol during synthesis (41). 

Organotin compounds such as monobutyltin oxide, the main substance used, accounting for 70% of consumption, dibutyltin oxide, monooctyltin oxide, and dioctyltin oxide are used in certain esterification and transesterification reactions, at concentrations between 0.001% and 0.5% by weight. They are used in the production of substances such as phthalates, polyesters, alkyd resins, fatty acid esters, and adipates and in trans-esterifications. These substances are in turn used as plasticizers, synthetic lubricants, and coatings. Organo-tins are used as catalysts to reduce the formation of unwanted by-products and also provide the required colour properties (ETICA, 2002). 

Two earlier studies (Kenar et al., 2005 Knothe et al., 2000) were conducted on the effects of compounds synthesized with hydrocarbon tail-group structures resembling those of FAME with attached bulky moieties. These studies examined novel fatty diesters made from reaction of diols with acids and diacids with 2-octanol in toluene solvent with p-toluene sulfonic acid catalyst and branched-chain esters of carbonic acid (carbonates) synthesized in nonyl alcohol with n-dibutyltin oxide catalyst. None of the synthesized compounds demonstrated effectiveness in decreasing CP or PP of SME. 

Microwave-assisted preparation of aryltetrazoleboronate esters 178 and 2,4-disubstituted-3-(5-tetrazolyl)pyridines 180 were obtained, respectively, from benzonitriles 177 <04OL3265> and nicotinonitriles 179 <04TL2571> with trimethylsilyl azide and dibutyltin oxide. Tetrabutylammonium fluoride was an efficient catalyst for the [3 + 2] cycloaddition reaction of nitriles with trimethylsilyl azide under solvent-free conditions <04JOC2896>. 1-Substituted tetrazoles 182 were synthesized by a [3+2] cycloaddition between isocyanides 181 and trimethylsilyl azide in the presence of hydrochloric acid in methanol <04TL9435>. 

Immiscible polyacrylates have been compatibilized through transesterification between pendent ester groups on one polyacrylate with pendent ester groups on another polyacrylate. Selected examples are listed in Table 5.38. Dibutyltin oxide was used as transesterification catalyst. 

The cis- and rans-cyclobutane-l,2-diols form cyclic complexes with dibutyltin oxide from which 2-hydroxycyclobutanone can be obtained by treatment with bromine. The cyclobutanone (867) furnishes an enol ester (868) with triethyl phosphite. " ... 

Hu and Lambla (1995) have blended EMAc (90-65 parts) with monohydroxy-terminated PS (10-35 parts) in an internal mixer at 180-220 °C in the presence of dibutyltin dilaurate or dibutyltin oxide catalyst. A compatibilizing copolymer arises from transesterification between pendent ester groups of EMAc and terminal hydroxy groups of PS. The effects oti blend properties of PS molecular weight were reported. The effects of processing conditions and addition of solvent on conversimi kinetics were studied. 

The preparations of racemic 1,3,4,6-tetra-O-allyl and 1,3,4,5-tetra-O-allyl myoinositol from myo-inositol, excess dibutyltin oxide and allyl bromide have been reported. The latter compound was resolved via its (-)camphanate ester. The 1,3.4-tri-O-allyl nQ o-inositol was also made by using three equivalents of dibutyltin oxide. 

Cadmium/zinc phosphite esters are also effective light stabilizers, as are WO3 and rare-earth-metal oxides. " Dibutyltin bis-isooctylthioglycolate is converted into the corresponding dibutylmonochlorotin ester and SnOCl2 during irradiation in PVC. ... 

Metals of groups III-VI (namely Ti, Sb, Ge, Bi), usually introduced as alkoxides, dialkyltin oxides R2SnO and carboxylates such as dibutyltin dilaurate, coordinate with the acylic oxygen of esters. 

If the only concern is the identification of the dialkyl groups attached directly to tin, then a method using methanolic sodium hydroxide solution is recommended (Figure 7.9). The thin-layer chromatographic method described is also suitable. For pure samples of dialkyltin carboxylates with no ester present, the time of reflux with alkali can usually be much reduced, the recovery and identification of the dialkyltin oxide, believed to be in polymeric form, still being quite satisfactory. In addition, maleic acid can be recovered fi om a sample of dibutyltin maleate after decomposition by this simplified method. 

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