Alkyl tin chlorides

Alkyltin Intermedia.tes, For the most part, organotin stabilizers are produced commercially from the respective alkyl tin chloride intermediates. There are several processes used to manufacture these intermediates. The desired ratio of monoalkyl tin trichloride to dialkyltin dichloride is generally achieved by a redistribution reaction involving a second-step reaction with stannic chloride (tin(IV) chloride). By far, the most easily synthesized alkyltin chloride intermediates are the methyltin chlorides because methyl chloride reacts directiy with tin metal in the presence of a catalyst to form dimethyl tin dichloride cleanly in high yields (21). Coaddition of stannic chloride to the reactor leads directiy to almost any desired mixture of mono- and dimethyl tin chloride intermediates ... 

Mercaptides are unchallenged as the ligand of choice for the other entities bonded to the tin, but carboxylates can also be used. Whereas a variety of mercaptans are used, the thioglycolic acid derivatives remain the largest single mercaptan. Dibutyltin bis(isooctyl thioglycolate) [25168-24-5] and butyltin tris(isooctyl thioglycolate) [25852-70A] are two common examples. These materials are produced by the reaction of the appropriate alkyl tin chloride or oxide, and the mercaptan. 

If the reaction temperature is controlled through the use of a low boiling solvent or other means, it is possible to isolate equimolar quantities of monoalkyl tin trichloride and tri alkyl tin chloride using a 1 1 ratio of tetraorganotin and tin tetrachloride ... 

The reaction of higher alkyl chlorides with tin metal at 235°C is not practical because of the thermal decomposition which occurs before the products can be removed from the reaction zone. The reaction temperature necessary for the formation of dimethyl tin dichloride can be lowered considerably by the use of certain catalysts. Quaternary ammonium and phosphonium iodides allow the reaction to proceed in good yield at 150—160°C (109). An improvement in the process involves the use of amine—stannic chloride complexes or mixtures of stannic chloride and a quaternary ammonium or phosphonium compound (110). Use of these catalysts is claimed to yield dimethyl tin dichloride containing less than 0.1 wt % trimethyl tin chloride. Catalyzed direct reactions under pressure are used commercially to manufacture dimethyl tin dichloride. 

Two approaches for the synthesis of allyl(alkyl)- and allyl(aryl)tin halides are thermolysis of halo(alkyl)tin ethers derived from tertiary homoallylic alcohols, and transmetalation of other allylstannanes. For example, dibutyl(-2-propenyl)tin chloride has been prepared by healing dibutyl(di-2-propenyl)stannane with dibutyltin dichloride42, and by thermolysis of mixtures of 2,3-dimethyl-5-hexen-3-ol or 2-methyl-4-penten-2-ol and tetrabutyl-l,3-dichlorodistannox-ane39. Alternatively dibutyltin dichloride and (dibutyl)(dimethoxy)tin were mixed to provide (dibutyl)(methoxy)tin chloride which was heated with 2,2,3-trimethyl-5-hexen-3-ol40. 

Tetrakis(triphenylphosphine)palla-dium(0), 289 Tributyl tin chloride, 315 of amines and other N-alkylations Potassium /-butoxide, 252 of carboxylic acids and acyl derivatives at the a carbon... 

Sn chemical shifts (ppm) of alkyl- and phenyl-tin chlorides... 

Various alkyl and aryltin compounds were determined in aquatic matrices, namely sediments, biota and water by means of gas chromatographic methods. In this work, comparisons of single or dual flame photometric detectors and electron capture detectors were reported (Tolosa et al., 1991). Sample preparations included acid digestion, extraction, formation of methyl derivatives and clean-up with alumina prior to gas chromatographic analysis. With the electron capture detector, cold on-column injection of organo-tin chlorides was studied. The conclusion was that a single or dual flame photometric detector equipped with a 600 nm interference filter yielded the best performance for determinations of tin species as methyl derivatives. Detection limits for the method using flame... 

In 1999 Trost and Schroder reported on the first asymmetric allylic alkylation of nonstabilized ketone enolates of 2-substituted cyclohexanone derivatives, e.g. 2-methyl-1-tetralone (45), by using a catalytic amount of a chiral palladium complex formed from TT-allylpaUadium chloride dimer and the chiral cyclohexyldiamine derivative 47 (equation 14). The addition of tin chloride helped to soften the lithium enolate by transmetala-tion and a slight increase in enantioselectivity and yield for the alkylated product 46 was observed. Besides allyl acetate also linearly substituted or 1,3-dialkyl substituted allylic carbonates functioned well as electrophiles. A variety of cyclohexanones or cyclopen-tanones could be employed as nucleophiles with comparable results . Hon, Dai and coworkers reported comparable results for 45, using ferrocene-modified chiral ligands similar to 47. Their results were comparable to those obtained by Trost. 

Under similar conditions, ethyl chloride gave only low yields of diethyltin dichloride, and attempts to alkylate tin, either in a sealed tube or under these flow conditions, with butyl chloride, butyl bromide, or bromobenzene were unsuccessful. 

Such reactions are therefore very suitable for preparing the hitherto relatively inaccessible alkyl tin hydrides 193). Diisobutylaluminum hydride reduces and alkylates tin tetrachloride isobutyltin(II) chloride results but Sn(iC4H9)2 has so far not been made in this way 239). 

TIN CHLORIDE, FUMING (7646-78-8) Reacts with moisture in air, forming hydrogen chloride fumes. Reacts with water, producing much heat, hydrochloric acid, tin oxide. Violent reaction with bases, oxidizers, organic materials, phenyl azide, silicon tetrahydride. Contact with alcohols, alkyl nitrates, amines, ethylene oxide, potassium, sodium, turpentine may cause fire and explosions. Contact with ethylene oxide may cause violent polymerization. Incompatible with glycidol. Attacks some plastics, rubber, and coatings. Corrosive to metals, especially in the presence of moisture. 

The manufacture of OTC involves a two-step reaction. The first step can be achieved in a number of different ways and involves reaction of tin tetrachloride (SnCU) with a suitable reagent to produce various tetraalkyltin compounds (ILjSn). In the second step, It Sn reacts with SnCU in a redistribution reaction to form less alkylated organotin chlorides such as R3SnCl, R2SnCl2, or RSnCls. From these products, various other tin derivatives can be produced. A direct reaction scheme is also possible whereby the organotin halides can be synthesized by a reaction between tin metal or alloy and alkyl halides. 

Anti-selectivity (to give 709) was observed when tin chloride (SnCU) catalyzed the reaction with either cis- or rranj-2-butene, but syn selectivity (to 710) was observed when alkyl aluminum catalysts were used (see Table 11.25).511... 

Organotin compounds a series of toxic alkyl tin compounds, such as butyl tin chloride and dibutyltin oxide used as plastic stabilizers and catalysts. 

Phosphoric Acid Inerts Alkyl Oimathyl Benzyl Ammonium Chloride Tributyl Tin Chloride/Ethylene Oxide/Amine 0.1 25 75 100 100/—... 

Methylol-terminated para-alkyl-substituted phenol formaldehyde resin is used as the vulcanizing agent for compounds based on butyl and EPDM rubber. The alkyl group is usually octyl. It is commonly used to cure butyl rubber where superior heat resistance is needed. Therefore, this vulcanizing agent is commonly used as the curative to make butyl bladders for repetitive curing of tires. It is also sometimes used in dynamic vulcanization with a tin chloride activator to make thermoplastic vulcanizates (TPVs). 

With the catalysis of strong Lewis acids, such as tin(IV) chloride, dipyrromethenes may aiso be alkylated. A very successful porphyrin synthesis involves 5-bromo-S -bromomethyl and 5 -unsubstituted 5-methyl-dipyrromethenes. In the first alkylation step a tetrapyrrolic intermediate is formed which cyclizes to produce the porphyrin in DMSO in the presence of pyridine. This reaction sequence is useful for the synthesis of completely unsymmetrical porphyrins (K.M. Smith, 1975). 

Tin(lV) chloride Alkyl nitrates, ethylene oxide, K, Na turpentine... 

---