Xanthogen disulfides

The extent of the long-chain branching of a series of ethyl xanthogen disulfide modified polymers carried to increasing conversion is shown in Table 1. No branches are found until 56% conversion. The gel point is a Htfle over 82%. Polymer rheology deteriorates between 56 and 82% conversion. 

Compounds with a thiocarbonyl a to the S-S bond such as the dithiuram (e.g. 8f2Al and xanthogen disulfides (e.g. 9)M have transfer constants that are much higher than other disulfides. In part, this may be due to the availability of another mechanism for induced decomposition (Scheme 6.9) involving addition to the C S double bond and subsequent fragmentation. Thiocarbonyl double bonds are very reactive towards addition and an addition-fragmentation mechanism has been demonstrated for related compounds (Section 6.2.3.5). 

It has also been reported that xanthogen disulfide (39) can act as a pho-toiniferter of the polymerizations of St and MMA (Eq. 42), being very similar to the polymerization with 13 [164,165] ... 

A simple method for the preparation of l,3-dithiol-2-ones 196 using radical methodology has been reported [95CC1429]. The reaction involves heating of diisopropyl xanthogen disulfide 193 with a terminal alkyne at 80 °C in the presence of a radical initiator. The reaction conditions are compatible with a variety of functional groups on the alkyne. 

An extension to telechelics was described almost 30 years ago by Uraneck [121] who reacted xanthogen disulfide with butadiene, leading to an original styrene-butadiene-styrene triblock copolymer formed in a radical way as follows ... 

A wide variety of disulfide derivatives has been proposed and among them the most simple R-S-S-R are those mainly used. Many investigations are still being conducted to increase the reactivity and the ease of cleavable of the S-S bond [12, 21], Specific initiators include alcoyle disulfides 42, where R represents an aromatic group [49, 222], dithiobenzoyl disulfides 43 [223], dialkyl xanthogen disulfides 44 [122], and finally thiuram disulfides 45 [224] ... 

Xanthogen disulfides, also called thio fonnic add dithio OO dialkylester, exhibit the following general structure ... 

In this synthesis, the reactivity of monomers M decreases in the classic order methyl acrylate > MMA acrylonitrile vinyl acetate > Sty, and DPn values increase linearly with the monomer conversion. Moreover, molecular weights range from 9000 (styrene) to 70000 (methyl acrylate) and the yields are quite high after only 3 h (ca. 90%) [230,231]. In addition, the authors observed that the initial value of DPn decreases with increase in the concentration of xanthogen disulfide [TX], an observation in agreement with the following kinetic equation ... 

In this equation, the second term only represents the normal behavior of the telomerization and the transfer constant of xanthogen disulfide (Cx), 4.44 and 0.29 for styrene and MMA, respectively. Such values are close to those previously determined for mercaptans [160-162],... 

OGEN DISULFIDE DITHIOBIS(THIOFORMIC ACID)-o,o-DIETHYL ESTER DIXANTHOGEN ETHYL XANTHOGEN DISULFIDE EXD K PREPARATION THIOPEROXYDICARBONIC ACID DIETHYL ESTER... 

ETHYLURETHANE see UVAOOO ETHYL VANILLIN see EQFOOO ETHYL VINYL ETHER see EQF500 ETHYL VINYL KETONE see PBR250 ETHYL TN XNITROSANnNE see NKFOOO ETHTT. XANTHOGEN DISULFIDE see BJUOOO ETHYL ZBL- TE see BJCOOO... 

The l,3-dithiol-2-ones 511 were conveniently prepared in a one-step reaction involving diisopropyl xanthogen disulfide 510 and terminal alkyl and aryl alkynes in the presence of radical initiators (Scheme 73) <1995GC1429,1998H(48)2003>. This synthetic strategy was also applied to the preparation of the quinoxaline derivatives 512 <1997J(P1)801>. 

Bis(t-butyl) phenol. See 2,6-Di-t-butylphenol Bis (n-butyl) sebacate. See Dibutyl sebacate Bis-butyl xanthogen. See Dibutyl xanthogen disulfide... 

Bis (ethylphenylcarbamodithioato-S,S )-(T-4)-zinc. See Zinc ethylphenyidithiocarbamate Bis(N-ethyl-N-phenyl) urea. See N,N -Diethyl-N,N -diphenylurea Bis (ethyixanthic) disulfide Bis (ethyixanthogen) disulfide. See Diethyl xanthogen disulfide Bis (4-fluorophenyl) sulfone. See 4,4 -Difluorodiphenyl sulfone 1,4-Bis (1-formamido-2,2,2-trichloroethyl) piperazine N,N -Bis (1-formamido-2,2,2-trichloroethyl) piperazine. SeeTriforine Bis (2-furfuryl) disulfide. See Difurfuryl disulfide... 

Dew Pearl AH-1 Dew Pearl TS-1. See Guanine DEX. See Diethyl xanthogen disulfide... 

Dithiobis (thioformic acid) 0,0-dibutyl ester. See Dibutyl xanthogen disulfide Dithiobis (thioformic acid)-o,o-diethyl ester. 

Dixanthogen. See Diethyl xanthogen disulfide Dixie day. See Kaolin Dixon Compd. 201 Dixon Compd. 7035. See Polytetrafluoroethylene Dixylyidisulfide... 

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