Di-tert-butyl acetylene

The kind of surface site catalyzing alkyne half-hydrogenation has been the subject of some speculation. Two possibilities are shown in Fig. 2.2. Certainly such a site should fit the evidence Burwell and associates obtained from the hydrogenation of di-tert-butyl acetylene (2,2,5,5-tetramethyl-3-hexyne). 31 They proposed that the molecule dislocated a surface atom, pulling it up out of the plane of the surface (Fig. 2.3). That work concluded that hydrogenation... 

Azete 6 crystallizes as reddish needles of mp 37°C. In its chemical properties, 6 shows analogies to cyclobutadienes. Its flash pyrolysis at 700°C gives di-tert-butyl acetylene and tBu-CN AG for this decomposition is very high, since a concerted (2 + 2)-cycloreversion is not allowed according to the Woodward-Hoffman rules ... 

Di-tert-butyl-l,2-dithiete was obtained by heating 2,2,5,5-tetramethylhex-3-yne (di-tert-butyl acetylene) with sulfur in benzene in an autoclave at 190 °C [24]. It is thermally stable and exists in the dithiete form. Valence isomerization into the dithione form would enhance the steric strain in the molecule. 

When colorless crystals of rac-s-trans-3,8-di-tert-butyl-l,5,6,10-tetraphenyl-deca-3,4,6,7-tetraene-l,9-diyne (123) were heated at 140 °C for 2 h, the ben-zodicylobutadiene derivative (126) was produced as green crystals. As shown in the sequence (Scheme 20), 123 is first isomerized to its s-ds-isomer (124), and intramolecular thermal reaction of the two allene moieties through a [2+2] conrotatory cyclization gives the intermediate 125, which upon further thermal reaction between acetylene moieties gives the final product 126 [19,22].This is another example of the crystal-to-crystal reaction. 

MePTZ = lO-methylphenothiazine 2,3-dpp = 2,3-bis (2-pyridyl)pyrazine 2,9-Me2-4,7-Ph2-phen = 2,9-dimethyl-4,7-diphenyl-l,10-phenanthrolme 2,9-Me2-phen = 2,9-dimethyl-1,10-phenanthroline 3,4,7,8-Me4-phen = 3,4,7,8-tet-ramethy 1-1,10-phenanthroline 4,4 - NH2 2-bpy = 4,4 -dia-mino-2,2 -bipyridine 4,4 -Me2-bpy = 4,4 -dimethyl-2,2 -bipyridine 4, 4 -Ph2-bpy = 4,4 -diphenyl-2,2 -bipyridine 4, 4 - Bu2-bpy = 4,4 -di-tert-butyl-2,2 -bipyridine 4,7-Me2-phen = 4,7-dimethyl-l,10-phenanthroline 4-MeOPh-HPh bpy = 4 -(4-methoxyphenyl)-6 -phenyl-2,2 -bipyridine 4-Me-phen = 4-methyl-1,10-phenanthroline 5,6-Me2-phen = 5,6-dimethyl-l,10-phenanthroline 5-Ph-phen = 5-phenyl-1,10-phenanthroline bimy = benzimidazol-2-ylidene biq = 2,2 -biquinoline bpy = 2,2 -bipyridine bpy-dvb-bpy = 1,4-bis[2-(4 -methyl-2,2 -bipyrid-4-yl)ethenyl]benzene bpy-pyrl = 4-(2-pyrrol-l-ylethyl)-4 -methyl-2,2 -bipyridine bpy-pyr2 = 4,4 -bis((3-pyrrol-l-ylpropyloxy)carbonyl)-2,2 -bipyridine BSA = bovine serum albumin BTA = bis(trimethylsilyl)acetylene chrysi = 5,6-chrysenequinone diimine COD = 1,5-cyclooctadiene DAB = 1,4-diaza-1,3-butadiene DFT = density functional theory dmb =1,8-diisocyano-/ -menthane dmb-tol = 4-methyl-4 -(iV-methyl-/ -tolylaminomethyl)-2,2 -bipyridine dmpe = l,2-bis(di-methylphosphino)ethane dmpm = bis(dimethylphosphino) methane dpmp = bis(diphenylphosphinomethyl)phenylphos-phine dppb = l,2-bis(diphenylphosphino)benzene dppe = l,2-bis(diphenylphosphino)ethane dpp-HCNN = 2,9-di-... 

Vovelle et al. [83] showed that the cool-flame region for diethyl ether was considerably extended by the addition of di-tert-butyl peroxide. The products of the normal combustion, cool flames and two-stage ignition were all examined [84] and found to include carbon monoxide and dioxide, water, acetaldehyde, methanol and methane, ethylene and acetylene. 

SCHEME 139. Oxidation of 4-acetylenic 2,6-di(tert-butyl)phenol with K3pe(CN)6 or Pb02... 

Miscellaneous Polymers - Soluble fluorescent extraction products from poly(acetylene) have been compared with those present in PVC. Photo-Fries rearran ments in the photodegradation of a Bis-Phenol-A poly(carbonate) are responsible for their stability. PTFE has been irradiated using high energy UV and found to give volatile fluorocarbons while photooxidation of poly(phenyl-ene) gives crosslinked and quinone methide products. A polyradical has been made based on poly(3,5-di-tert-butyl-4-[(2,4,6-tri-tert-butylphenyl)oxalato]phe-... 

Figure 3.5. UPS spectra of (a) poly[(3,5-di-tert-butyl-4-hydroxyphenyI)acetylene] and (b) poly(3,5-di-terf-butyl-4-hydroxystrene), (Reprinted with permission from ref 54, The Soc, Polyni. Sci., Japan)...

In a similar manner 1,3-di-ferf-butyl-2-phenylcyclopropenc (4) gave both di- ert-buty 1- and tert-butyl(phenyl)acetylenes, as well as an enone derived from the normal epoxidation of the cyclo-propene double bond. The mechanism by which the alkynes are formed is not clear, although radical scavengers did not significantly affect the reaction and addition of acetate did not lead to this being incorporated. 

Hexane. 3500—1300 cm. Thin film 2-Methylpentane. 3500—1300 cm . Thin film Dec-l-ene. 3500—1300 cm. Thin film /rfl 5-Stilbene. 1300—400 cm". KBr disc Styrene. 3500—1300 cm". Thin film Styrene 1300—400 cm". Thin film Phenyl Acetylene. 3500—1300 cm". Thin film Phenyl Acetylene. 1300—400 cm". Thin film Aromatic substitution patterns. 2000—1600 cm" para-Cresol. 3500—1300 cm". I.M. CCI4 solution tert-Butyl methyl ketone. 4000—650 cm". Thin film -Heptaldehyde. 4000—650 cm". Thin film Di-/sopropyl ether. 4000—650 cm". Thin film Acetic Anhydride. 4000—650 cm". Thin film Propionic acid. 4000—650 cm". Thin film Propionic acid. 3500—2000 cm". Solution 0.005M CCI4 Methyl salicylate. 4000—650 cm . Thin film n-Butylamine. 4000—650 cm". Thin film Benzamide. 3500—1300 cm". KBr disc Methionine. 4000—650 cm". KBr disc Benzonitrile. 3500—1300 cm". Thin film Benzonitrile. 1300—400 cm". Thin film A-Methyl acetamide. 3500—650 cm". Thin film Methyl acrylate. 4000—650 cm". Thin film Benzoyl chloride. 4000—650 cm". Thin film Triphenyl phosphate. 3500—1300 cm". Melt Triphenyl phosphate. 1300—400 cm". Melt Di-wopropyl sulphone. 4000—650 cm". Melt Nitrobenzene. 4000—650 cm". Thin film Dimethyl sulphoxide. 4000—650 cm". Thin film Polymeric silicone. 4000—650 cm". Thin film Calcium sulphate Dihydrate. 4000—650 cm". KBr disc... 

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