Aliphatic mercaptans

The thioalcohols have a pronounced acidic character. The alkali salts of the aliphatic mercaptans are, indeed, very largely hydrolysed by water, but the aromatic compounds, on the other hand, can be... 

Unavailable because experimental methods for estimation of this parameter for aliphatic mercaptans are lacking in the documented literature... 

Butadiene is available commercially as a liquefied gas underpressure. The polymerization grade has a minimum purity of 99%, with acetylene as an impurity in the parts-per-million (ppm) range. Isobutene, 1-butene, butane and cis-l- and Zrc//7.s-2-butcnc have been detected in pure-grade butadiene (Miller, 1978). Typical specifications for butadiene are purity, > 99.5% inhibitor (/c/V-butylcatecliol). 50-150 ppm impurities (ppm max.) 1,2-butadiene, 20 propadiene, 10 total acetylenes, 20 dimers, 500 isoprene, 10 other C5 compounds, 500 sulfur, 5 peroxides (as H2O2), 5 ammonia, 5 water, 300 carbonyls, 10 nonvolatile residues, 0.05 wt% max. and oxygen in the gas phase, 0.10 vol% max. (Sun Wristers, 1992). Butadiene has been stabilized with hydroquinone, catechol and aliphatic mercaptans (lARC, 1986, 1992). 

Mercaptans. The aliphatic mercaptans with four or fewer carbon atoms have rather powerful insecticidal properties and can be used as fumigants against certain insect species. This is not true of those compounds containing over four carbon atoms and also not true of aromatic mercaptans. 

Aliphatic Mercaptans 3 Heterocyclic Mercaptans 7 Heterocyclic Thioethers 11 Heterocyclic Disulfides 7 Thiophenes 22 Thiazoles 6... 

The primary disadvantages of polymercaptans over other fast-reacting curing systems are (1) skin irritation caused by aromatic mercaptans (aliphatic mercaptans are less der-matitic than common polyamides) and (2) an objectionable sulfur odor, especially when the vapor pressure of the mercaptan is relatively high. 

PROP Compounds containing the -SH group bound to carbon. Also called thiols. SAFETY PROFILE Generally they have a very offensive odor that may cause nausea and headache. High concentrations of vapor can produce unconsciousness with cyanosis, cold extremities, and rapid pulse. A common air contaminant. Dangerous when heated to decomposition they almost always emit highly toxic fumes of SO. They may react with water, steam, or acids to produce toxic and flammable vapors. Aliphatic mercaptans are flammable. They can react violently with powerful oxidizers such as Ca(OCl)2. 

This reaction is analogous to similar methods for the preparation of ethers (methods 113 and 116), Both simple and mixed sulfides may be made from aliphatic mercaptans or thiophenols. The sodium mercaptides are formed from the mercaptans and aqueous or alcoholic solutions of sodium hydroxide or alcoholic sodium ethoxide. Alkylation is effected by halides, alkyl sulfates, or esters of sulfonic acids. The over-all yields of sulfides are usually above 70%. r-Butyl mercaptan is alkylated directly by /-butyl alcohol in strong sulfuric acid to give /-butyl sulfide in 87% yield. ... 

Sulphonic Acids.—When, however, an aliphatic mercaptan or thio- lcohol is oxidized we obtain a compound, containing a sulphuric acid residue, known as a sulphonic acid. 

Aliphatic mercaptans also give HNF2, but the reaction is not as clean and much N2F4 is reduced to N2. 

Butadiene is stored in a cool and well-ventilated location separated from combustible and oxidizing substances. Small amounts of stabilizers, such as o-dihydr-oxybenzene, j)-ferf-butylcatechol, or aliphatic mercaptans, are added to prevent its polymerization or peroxides formation. The cylinders are stored vertically and protected against physical damage. 

Thiols, also called aliphatic mercaptans, with the formula RSH, are the sulfur analogs of alcohols. Thiols generally show stronger molecular ion peaks than the equivalent alcohols. Looking back at Table 10.4, sulfur has a signihcant isotope. This gives rise to an enhanced M + 2 peak in the mass spectrum of sulfur-containing compounds. 

Classification Sat. aliphatic mercaptan Empirical C2H6S Formula CH3CH2SH... 

Classification Saturated aliphatic mercaptan Empirical CsHaS Formula CH3CH2CH2SH Properties Colorless mobile liq., offensive cabbage-like odor sol. in ethanol, other alcohols, acetone, diethyl ether, benzene, propylene glycol, oxygenated soivs. si. sol. in water m.w. 76.16 dens. 0.840 (20/4 C) m.p. -113 C b.p. 67-68 C flash pt. -20 C ref. index 1.438 (20 C) very weak acid... 

STUDIES OF STYRENE COPOLYMERIZATION WITH RUBBER. III. THE PROCESS PECULIARITIES BROUGHT ABOUT BY THE PRESENCE OF ALIPHATIC MERCAPTANS... 

With the increase of monomer conversion the polystyrene MW is increasing. The higher the initial NLM concentration, the faster it achieves the MW obtained under the same conditions but without the regulator at a styrene conversion equal to 10-30%. These trends are characteristic for styrene polymerization in the presence of BP and TBPB with the other aliphatic mercaptans as well. Figure 1 shows that decrease in the length of the t-mercaptan results in lowering of the reaction rate. 

The data allows us to propose the following mechanism of styrene polymerization in the presence of peroxide initiators and aliphatic mercaptans the regulator interacts with the initiator forming organic acids, disulfides and other products disulfides in their turn begin interactions with the initiators but at a lower rate than mercaptans this reaction is proceeded by the faster consumption of the benzoyl peroxide in the presence of different mercaptans, but there was no increase of radical formation rate. 

Of the compounds containing a sulfur atom in the molecule, mer-captans possess comparatively high inhibiting effectiveness. Hence, the use of mercaptobenzimidazole [50, 51], mercaptobenzothiazole, (S-naphthylthiol, and certain aliphatic mercaptans, for example, dodecyl mercaptan [41], is recommended for polyolefins. However, to guarantee the desired stability to oxidation under the conditions of reprocessing of the polymer at temperatures of 200-250°C, a comparatively high concentration of such stabilizers (of the order of 1% by weight) is required,... 

R-SH NHF2 NHF2 synthesis from N2F4 and thiophenol or aliphatic mercaptanes, for details, see Fluorine Suppl. Vol. 5 [16, 17]... 

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