Interfacial condensation technique

Recently Carraher, Naoshima and coworkers effected the modification of polysaccharides employing organostannanes and bis(cyclopenta-dienyl)titanium dichloride, BCTD (20-25). Here we report the modification of dextran employing the interfacial condensation technique using various phase transfer agents utilizing BCTD and dibutyltin dichloride, DBTD. 

The use of the low-temperature interfacial condensation technique to prepare polyamides and various other polymers has been reviewed in Refs. 2 and 3. 

A wide variety of group 4 (Ti, Zr, Hf) metallocene-containing polyethers, polythioethers, polyesters, polyamines, polyoximes, and polyamidoximes has also been reported. Their synthesis, which is based on the polycondensation (with HCl elimination) of CP2MGI2 with difunctional organic species such as diols, dithiols, etc. (Scheme 14), was carried out either in aqueous solution or using interfacial condensation techniques, based upon the... 

Xylan reacts with triphenylantimony dichloride using the classical interfacial condensation technique. The products are polyethers with Sb-O-R moieties. 

Very similar, wholly aromatic polyamides, with very regular structures, which reportedly result in better flexibility and higher temperature resistance, were reported. Preparation of these ordered copolyamides can be illustrated as follows. V,V-m-phenylene-bis(m-aminobenzamide) is formed first and then reacted with isophthaloyl chloride by interfacial condensation techniques to yield a product that melts at about 410 C ... 

Carraher recently reviewed these s3mtheses, emphasizing polymerizations employing the interfacial condensation technique. For the synthesis of poly-phosphonate and polyphosphate esters and amides Carraher, Millich and others have reported that hydrolysis of the acid chloride typically limits the product yield and molecular weight.The synthesis of polyesters ... 

We recently reported the modification of dextran as a function of a number of reaction systems. Briefly modification was accomplished employing both aqueous and nonaqueous interfacial condensation techniques and utilizing the aqueous interfacial system except employing copper-diamine aqueous solutions. While some organic solution condensations permitted the successful condensation of organostannanes with dextran, the vast majority of attempted systems did not give the desired product. 

The present study involves the modification of dextran employing the classical aqueous interfacial condensation technique ... 

We have synthesized a number of phosphorus-containing polymers utilizing the condensation of phosphorus acid chlorides amd the diisocyanate with a variety of Lewis bases utilizing the interfacial condensation technique. ... 

It is, however, beyond the scope of this review to discuss this very extended field which is only limited by solubility properties and by the relatively low concentration of the end groups. A further progress and even greater extension may, however, become possible by changing the technique of condensation as for instance by using the interfacial condensation or by working in more controlled experimental conditions. 

In this technique, two types of reactants are placed separately in two immiscible solvents, one of which is water. Polymerisation takes place at the interface in the presence or absence of a phase transfer catalyst (PTC) such cetyl tributyl ammonium bromide (CTAB), benzyl dimethyl hexadecyl ammonium chloride (BDMHDAC), tetramethyl ammonium bromide or tetraphenyl phosphonium bromide. This process is carried out by agitation or under static conditions. This technique is effective for condensation polymers or for the formation of polyaniline nanofibre. The advantages of the interfacial polymerisation technique include the use of simple equipment, nfild reaction conditions and flexibility in the ratio or purity of reac-... 

The polymeric material is derived from the interfacial condensation polymerization between titanocene dichloride and 2-nitro-p-phenylenediamine (Figure 1). This product was initially synthesized by us in 1975 employing both the interfacial and solution polymerization techniques. [19]... 

Polymerization may be carried out with monomer alone (bulk), in a solvent (solution), as an emulsion in water (emulsion), or as droplets, each one comprising an individual bulk polymerization, suspended in water (suspension). All four methods are commercially applied to radical-initiated chain polymers such as polystyrene. Most ionic and coordination complex systems are inactivated by water, so that only bulk or solution methods can be used. Also, rather few condensations are carried out in emulsion or suspension. However, ethylene dichloride and sodium polysulflde are condensed to give ethylene polysulflde rubber and sodium chloride in an aqueous emulsion. Gas-phase polymerization and interfacial condensation are special techniques, which are mentioned in Section 5.3. 

One previous synthesis of ferrocene-containing condensation polymers via interfacial methods at room temperature has been reported by Knobloch and Rauscher, who formed low molecular weight polyamides and polyesters by reacting l,l -bis(chloro-formyl)ferrocene with various diamines and diols. Further, Carraher and co-workers have utilized interfacial techniques in the formation of other types of organometallic polymers. 

Bis(hydroxymethyl) furan and 5-hydroxymethyl furfural (available from C6 sugars) have been oxidized to furan-2,5-dicarboxylic acid (44)- Linear polyesters, polyurethanes, and polyamides containing these monomers have been described in the literature (45-43) and have been made via condensation polymerization techniques including bulk, solution, and interfacial mixing procedures. Gandini (5,34) reviewed the poly condensation reactions up to 1986 and... 

This group of techniques is based upon the analysis of electrons backscattered or emitted from metal surfaces. The shallow escape depths of these particles make their use most suitable for interfacial studies since the information they bear are characteristic only of the near-surface layers on the other hand, the short mean-free paths necessitate a high-vacuum enviromnent. The major limitation has always been the possibility of stractural and compositional changes upon emersion (removal from solution under potential control) and transfer of the electrode into the UHV environment. However, numerous studies have established that the compact layer remains largely unperturbed upon emersion, " unless the emersed layer contains feebly bound non-condensed species. 

Density functional theory is a powerful tool to study many phenomena in physical chemistry and chemical engineering. It was popularized in the early 1960s by a number of authors [72-74]. But it is not until the 1980s that this theory had found widespread appHcations in many interfacial problems. Capillary condensation in pore was systematically studied [75], and the first paper [76] applying this technique to the problem of PSD determination of carbon particle appeared in 1989. This work used a local DFT, and it is now superseded by the NLDFT, which was developed by Tarazona and Evans [77-79]. This is the method that is now widely used in the characterization of pore size distribution. 

J/n < 6,000). Often, no analytical data or structural characterization was provided. Room-temperature interfacial polycondensation methods were also investigated as a convenient alternative to classical polycondensations. Such methods were first reported for the preparation of polyamides and polyesters from the reaction of l,l -ferrocenyldi-carbonyl chloride with several diamines and diols. The synthesis of polyurethanes using this technique was also reported and involved the condensation of l,T-ferrocenedimethanol and l,T-bis(dihydroxyethyl)ferrocene with diisocyanates. Once again, however, these polymers possessed low molecular weights.The early research in these areas has been summarized and critically reviewed and will not be discussed further here. ... 

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