Propylene sulphide

Waldman D A, Kolb B U, McCarthy T J and Hsu S L 1988 Infrared study of adsorbed monolayers of poly(styrene-propylene sulphide) (PS-PPS) block copolymers Polym. Mater. Sc/. Eng. 59 326-33... 

These include copolymers of propylene sulphide with 3-10% of allyl glycidyl thioether and which may be considered as a thio-analogue of the propylene oxide-allyl glycidyl ether rubber briefly mentioned in Section 19.5 ... 

Thiadisilacyclopropanes result from the reaction of disilenes with sulphur and episul-phides. From the mechanistic standpoint, the reaction of RR,Si=SiRR/ is of great interest and the separation of the (E)- and (Z)-isomers (trans and cis) [R = 2,4,6-( -Pr)3C6H2, R = t-Bu] has led to the separate addition of sulphur to each. This occurs within a minute to give trans and ds-isomers, respectively, the latter with slightly different Si—S bond lengths60. Propylene sulphide reacted similarly, and the reaction of (i-Bu)2Si=Si(Bu-t)2 with thiophene leads to sulphur abstraction with the formation of the thiadisilacyclo-propane, with Si—S bonds of 217.1 pm, along with the l,2-disilacyclohexa-3,5-diene and 2,6-disilabicyclo[3.1.0]hex-3-ene (equation 29)61. 

The vanadium(III) complex 34 has a Si—Se bond length of 230.3 and, like the Ph3Si derivative, reacts with styrene oxide, propylene sulphide and selenium or Ph3P=Se, to give the vanadium)V) derivative (equation 47)98. 

SCHEME 24. Proposed mechanism for the copolymerization of a propylene sulphide and bis[bis(tri-methylsilyl)amido]germanium... 

Some cadmium compounds, including simple salts, were revealed to be excellent catalysts for the enantiosymmetric polymerisation of propylene sulphide [156,157], For instance, the proportion of isotactic diads in the polypropylene sulphide) sample obtained in polymerisation with the cadmium (7 )-tartrate catalyst was more than 95%, higher than the 69% which was characteristic of a polymer sample prepared using the zinc (i )-tartrate catalyst [158]. The superior stereoselectivity of the cadmium (i )-tartrate catalyst is also borne out by the more effective separation into fractions having opposite optical rotations of the polypropylene sulphide) yielded by cadmium tartrate, compared with that yielded by zinc (i )-tartrate. Note the quite different behaviour of these two catalysts in terms of their stereoelectivity in the polymerisation of propylene sulphide only very slight optical activity was found for the polypropylene sulphide) sample prepared using cadmium tartrate, whereas that associated with the polymer sample obtained with zinc tartrate was found to have a much higher value [158]. 

As regards the dimethylcadmium-(7 )-(—)-3,3-diethyl-1,2-butanediol (1 1) catalyst, it was characterised by a lower stereoelectivity than the diethylzinc-(R)-(—)-3,3-dimethyl- 1,2-butanediol (1 1) catalyst in enantioasymmetric polymerisations of propylene sulphide, cA-2-butene sulphide and cyclohexene sulphide, but the elected chirality was opposite to that found for polymers obtained with the zinc-based catalyst [159]. 

The above stereospecific tiirane polymerisations have generally been run in heterogeneous systems. Such conditions essentially make it impossible to determine the detailed structure of active species involved in these polymerisations. Thus, enantiosymmetric and enantioasymmetric polymerisations of propylene sulphide have also been studied in a homogeneous phase by using chiral cadmium thiolates of cysteine esters and chiral cadmium carboxylates of cysteine and methionine [157,160-164]. The most studied is living polymerisation using the cadmium derivative of the isopropyl ester of (.S)-cysteine [160] ... 

An excellent catalyst for the living polymerisation of propylene sulphide appeared to be /V- me t h y l-tetraphenylporphinatozinc propanethiolate [(Mtpp) ZnSPr]. Polymerisation with this catalyst proceeds at room temperature via (N-methyl-tetraphenylporhinato)zinc thiolate as the growing species [165] ... 

Propylene sulphide was found [246] to undergo copolymerisation with carbon dioxide in the presence of the triethylaluminium pyrogallol (2 1) catalyst, yielding copolymers, polypropylene thioether-monothiocarbonate)s, containing propylene thiocarbonate units in an amount reaching 42 mol.-%, apart from the predominating propylene sulphide units (Table 9.4) ... 

Attempts to use the diethylzinc-pyrogallol (2 1) catalyst to copolymerise propylene sulphide and carbon dioxide failed, since the content of propylene thiocarbonate units in the copolymers formed was small and did not exceed 10 mol.-%. It has also been observed that the presence of carbon dioxide in this copolymerisation system causes a lowering of the molecular weight and yield of the copolymer formed. Thus, it has been suggested that propylene sulphide homopolymerisation was favoured over cross-propagation with carbon dioxide in the presence of a zinc-based coordination catalyst because of higher HSAB symmetry of the system in the former case. The zinc atom in the Zn-S unit of the catalyst is a rather soft acid and will prefer reaction with a soft base such as propylene sulphide rather than with hard carbon dioxide. The presence of a hard acid centre in the triethylaluminium-based catalyst should result in an increase in the affinity of the catalyst towards carbon dioxide [247],... 

Ethylene sulphide and propylene sulphide have been reported by Soga et ol. [249,250] to copolymerise with carbon disulphide in the presence of catalysts such as diethylzinc, diethylcadmium and mercury bis( -butanethiolatc), yielding poly(alkylene thioether-trithiocarbonate) copolymers (Table 9.4). The content of ethylene trithiocarbonate units in the ethylene sulphide/carbon disulphide copolymer obtained with the most efficient catalyst, mercury bis( -butanethiolate), was in the range 50-70 mol.-% [249]. 

Poly(propylene sulphide) Poly(phenylene sulphide)... 

Bearinger, J.P. Terrettaz, S. Michel, R. Tirelli, N. Vogel, H. Textor, M. Hubbell, J.A. Chemisorbed poly(propylene sulphide)-based copolymers resist biomolecular interactions. Nat. Mater. 2003, 2, 259-264. 

Another variant of initiation by naphthalenide was proposed by Sigwalt (12), who studied the anionic polymerization of propylene sulphide. Formation of propylene in the course of this reaction led him to a following mechanism ... 

Although a conventional initiation of anionic polymerization by alkyl lithiums involves their addition to a C=C bond, an exceptional mode of initiation associated with ring-opening polymerization was reported by Morton and Kammereck186). Ethyl lithium seems to initiate polymerization of propylene sulphide, but the reaction involves first a desulphuration of the monomer, leading to the formation of lithium mercaptide ... 

The initiation of propylene sulphide polymerization by a-sulphonyl type carbanions, -S02, CH2Li, proceeds in a conventional way187). 

Fig. 69. Plot of propagation constant, k , of poly-propylene sulphide polymerization with kryptated cations in THF vs. mole fraction of free ions. Note the increase of kp at lower/indicating higher reactivity of kryptated ion-pairs than of the free ions...

The most interesting results were obtained in polymerization studies performed with kryptated cations. Kinetics of propylene sulphide polymerization in THF at — 30 °C with Na+, (2,2,2) led to the results shown in Fig. 69. The propagation of these ion-pairs turned out to be higher than of the free anions. On the whole propagation constant of ion-pairs increases with the radius of the cation, viz. at - 30°C in THF ... 

As could be expected, the complexation facilitates the dissociation of ion-pairs. For example, the dissociation constant of sodium ion-pairs in THF at — 30 °C increases one thousand-fold on addition of (2,2,2)kryptate. An interesting study of propylene sulphide polymerization initiated electro-chemicaUy in dimethyl formamide was reported by Man-goli and Daolio451). 

Polymeric nanoparticles (Pluronic-stabilized poly(propylene sulphide) nanoparticles) with controlled size (20 0 nm) have been successfully delivered to the lymph nodes via interstitial flow, in order to target a large number of... 

Poly(ethylene oxide-6-propylene sulphide-6-ethylene oxide), PEO-PPS-PEO Water 72... 

Penczek, Slazak, and Duda have reported that the anionic copolymerization of propylene sulphide with sulphur leads to the formation of polymers based on the repeat unit —CHiCH(CH,)S -, where n can be as large as 12. This claim has been questioned by Aliev et al. on the basis of alleged anomalies in the n.m.r. spectra they suggest that the polymers are actually mixtures of elementary sulphur and copolymer having r < 2. Penczek et al have replied that non-anomalous spectra are obtained when the crude polymers are freed from low-molecular-weight cyclic polysulphides and that the absence of elemental sulphur is proved by the transparency of films cast from solution. 

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