Cocondensation

PC-cocondensates (BPA-PC, bensyl-substituted PC, four-ring bisphenol-PC, PC with lateral phenyl Bayer AG... 

The bulk polycondensation of (10) is normally carried out in evacuated, sealed vessels such as glass ampules or stainless steel Parr reactors, at temperatures between 160 and 220°C for 2—12 d (67). Two monomers with different substituents on each can be cocondensed to yield random copolymers. The by-product sdyl ether is readily removed under reduced pressure, and the polymer purified by precipitation from appropriate solvents. Catalysis of the polycondensation of (10) by phenoxide ion in particular, as well as by other species, has been reported to bring about complete polymerisation in 24—48 h at 150°C (68). Catalysis of the polycondensation of phosphoranimines that are similar to (10), but which yield P—O-substituted polymers (1), has also been described and appears promising for the synthesis of (1) with controlled stmctures (69,70). 

Various alkyl-substituted pyridine derivatives are formed from the condensation of butyraldehyde with ammonia at high temperatures. For example, cocondensation of //-butyraldehyde with acroleia [107-02-8] and ammonia at 400°C over a borosiUcate 2eohte gives 3-ethylpyridine [536-78-7] ia 70% yield... 

Another approach to increase the heat distortion temperature is to produce cocondensates of bisphenol A with bishydroxyphenyl fluorene. Some variations of this copolymer had heat distortion temperatures in excess of 200°C and with the potential to be produced at lower cost than such temperature-resistant thermoplastics as polysulphones and polyetherimides. Plans to develop this material were however abandoned when it was found, during trials of test materials, that workers developed skin rashes said to be similar to those encountered on contact with poison ivy. 

Diem, H., Fritsch, R., Lehnert, H., Matthias, G., Schatz, H. and Wittmann, O., German patent DE 3125874. Process for the preparation of cocondensates which form weatherproof adhesive bonds. Assigned to BASF AG, 1981. 

Where the acid condensate is corrosive, neutralisers, e.g. ammonia or neutralising amines, can be injected into the vapour stream to cocondense with the acid vapour. This is the practice with the overheads of a crude oil pipestill (Fig. 9.4). 

By use of quantitative, metal-atom, matrix-cocondensation techniques and the kinetic analysis previously discussed, the dimeric spe-... 

Simultaneous with this work, Ozin and co-workers were independently investigating other bimetallic combinations. When Cr and Mo were cocondensed (133) together in Ar, using the apparatus shown in Fig. 11, a controlled pathway to CrMo was found. This molecule had previously been observed in the gas phase (30) from flash photolysis of a mixture of Cr(CO)6 and Mo(CO)g vapors. The molecule was identified (UV-visible spectroscopy) by a series of Cr/Mo/Ar concen-... 

Fig. 19. The optical spectrum of the products of a Ag Kr — 1 10 cocondensation reaction, (A) after deposition at 10-12 K, and (B) after 60-min, narrow-band (8 nm), 325-nin continuous irradiation from an Oriel 500-W xenon lamp-Schoeffel monochromator assembly (152).

Fig. 25. Portions of the IR spectra of the products of the cocondensation of Ni atoms with CO/Ar (1 250). A through E refer to increasing, total-metal concentration. The inset is a curve-resolved version of spectrum B (96).

V(CO)e generated by cocondensing presynthesized V(CO)6 with N2 at 10 K has been observed (44, 45). As suggested in a metal-atom study (125), the results indicated that a static, Jahn-Teller distortion is present. Matrix MCD also proved useful in confirming the predicted paramagnetism of Fe(CO)4 (45) (produced by photolysis of Fe(CO)5). In addition, matrix MCD was used to detect such paramagnetic species as MnOaCU in the presence of MnOsCl (45). 

Further reactions of gold atoms (132) with mixed OJCO matrices led to some interesting results. By cocondensing Au atoms with equimolar mixtures of Oj/CO at 10- 12K, a single compound was isolated which, by means of = C 0/> 02, and C 0/ = C 0/ HD /... 

Manganese atoms were cocondensed with Oj, N2O, or O3, to afford MnO, Mn02, MnOs, and Mn04 (197). The actual reactions involved were... 

A number of investigations of the copper-group oxides and dioxygen complexes have been reported. The electronic spectra of CuO, AgO, and AuO were recorded in rare-gas matrices (9), and it was found that the three oxides could be formed effectively by cocondensation of the metal atoms with a dilute, oxygen matrix, followed by near-ultraviolet excitation. The effective wavelengths for CuO or AgO formation were X > 300 nm and for AuO was X > 200 nm. In addition, the laser fluorescence spectrum of CuO in solid Ar has been recorded (97). 

Titanium atoms have been cocondensed with CO and N2 matrices (138) and the products identified as TitCOlg and Ti(N2)e. The IR data... 

As was suggested in the preceding discussion, most of the arene complexes isolated by metal-atom techniques are benzene derivatives. However, heterocyclic ligands are also known to act as 5- or 6-electron donors in transition-metal 7r-complexes (79), and it has proved possible to isolate heterocyclic complexes via the metal-atom route. Bis(2,6-di-methylpyridine)Cr(O) was prepared by cocondensation of Cr atoms with the ligand at 77 K (79). The red-brown product was isolated in only 2% yield the stoichiometry was confirmed by mass spectrometry, and the structure determined by X-ray crystal-structure analysis, which supported a sandwich formulation. 

The cocondensation of iron atoms with stjrrene or phenylacetylene at 77 K produces (14) a low yield of polystyrene and a triphenylbenzene. 

Chromium atoms were cocondensed with benzyl sulfide at 77 K (35), the primary result being desulfurization to form bibenzyl and trans-stilbene. Coordination compounds were not characterized in this system. 

It has, however, proved possible to synthesize the following chromium complexes via a 77 K, Cr-atom, cocondensation reaction with 2,-... 

When chromium atoms were cocondensed at 77 K with 1,7-cyclodeca-diyne (38), complexation was not observed however, an organic trimer of the starting material was formed. Standard, organic characterization-techniques showed that this trimer is the one depicted, rather... 

In addition, Lagowski and Simons showed (80) that the black, nickel-containing substances produced by the cocondensation of nickel atoms and alkynes are active, homogeneous catalysts for the oligomerization of terminal acetylenes under mild conditions. Table XVIII shows the yields of the oligomerization of propylene by these catalysts. 

Somewhat related to the desulfurization reaction already discussed (35), the cocondensation of Cr and Fe atoms with thiophenes at 77 K leads to desulfurization of the thiophene (22, 187). Warm-up of the iron- thiophene cocondensate in a CO atmosphere produces tricarbon-ylferrocyclopentadiene-tricarbonyliron. 

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