Acetylene Hydroquinone

Acetylene, clathrate in hydroquinone, 7 hydrate thermodynamic data and lattice constants, 8 Acrylamides, polymerization of, 181 Acrylonitrile, 155 Activity coefficients, 125... 

The same comparison was made for hydroquinone for a given conversion of 80%, which is exhibited in Fig. 12.8. Unlike catechol and 3-methycatechol, products resulting from hydroquinone cracking in the presence and absence of iron oxide are identical. A peak found at m/z 110 is probably hydroquinone and its fragment ions are at m/z 39, 55, and 81. The identities of some of the products (Fig. 12.8a and b) are likely to be as follow acetylene (m/z 26), vinyl acetylene (m/z 52), butadiene (m/z 54), cyclopentadienone (m/z 80), and 1,4-benzoquinone (m/z 108). To confirm the differences in chemistry between catechols and hydroquinones, 2,3-dimethyhydroquinone was subjected to the same comparison. 

The thermally unstable acethylenic thiols 142, which are produced from the corresponding halogen substituted acetylene derivatives 141, have been reported to undergo, in the presence of hydroquinone and nitrogen at — 15°C, heterocyclization to the derivatives 143, 144, and 145 (Eq. 22). ... 

Oliveri-Mandald found that HN3 adds to benzoquinone to give azido-hydroquinone [44]. Extension of this reaction to acetylenes led to triazoles [45] and failed entirely with cinnamic acid, fumaric acid, styrene, vinyl bromide, ethylene, and other olefinic compounds [46]. 

Other chemicals present in acrylonitrile production or in other non-acrylonitrile operations on sites of the companies in the epidemiological study by Blair et al. (1998) include acetylene, hydrogen cyanide, propylene, ammonia, acetic acid, phosphoric acid, lactonitrile, hydroquinone, sodium hydroxide, sulfuric acid, acrylamide, acetone cyanohydrin, melamine, methyl methaciydate, zweto-methylstyrene, urea, methacrylonitrile, butadiene, ammonium hydroxide and ammonium sulfate (Zey et al., 1989, 1990a,b Zey McCammon, 1990). 

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). 

Carbonylation of the parent acetylene via stoichiometric or catalytic reactions involving transition-metal carbonyl complexes has been extensively studied. Various types of carbonylation reactions of acetylene were discovered. In 1968, Pino et al. [30] reported on the synthesis of hydroquinone via a Ru3(CO)12-cat-alyzed carbonylation of acetylene with H2 or H20. The product formally consisted of two molecules of acetylene and CO, and one molecule of H2 (Eq. 14). To achieve a good yield of hydroquinone, the H2 pressure must be kept under... 

Considerable effort has been devoted to achieving the intermolecular catalytic Pauson-Khand reaction. The mthenium complex-catalyzed reaction of an alkyne with an alkene such as ethylene or 2-norbornene under CO gave hydroquinone derivatives [79], with CO (2 mol) being introduced into the products (Eq. 11.36). This reaction is the first example of the preparation of hydroquinone derivatives by the reaction of alkynes and alkenes with CO, while hydroquinone is synthesized by the ruthenium-catalyzed reaction of 2 mol acetylene with 2 mol CO (Eq. 11.37) [80]. 

Mercuric oxide, HgO (yellow modification or the less reactive red modification), resembles silver oxide in its oxidizing properties. This reagent transforms phenols and hydroquinones into quinones [383, 384] and is used especially for the conversion of hydrazones into diazo compounds [355, 386, 387, 388, 389, 390, 391, 392]. Dihydrazones of a-diketones furnish acetylenes [393, 394, 395, 396], A -Aminopiperidines are dehydrogenated to tetrazenes [397] or converted into hydrocarbons [395]. 

Ruthenium carbonyl, Ru3(CO)12, has been reported to catalyze the cyclohydrocarbonylation of acetylene to give hydroquinone ... 

The reaction proceeds in THF at 220°C (127-bar CO, 5-bar H2) after 170 min, 59% of the acetylene is converted into hydroquinone (CT 449) (268). A similar reaction has been described in a patent, giving lower yields of hydroquinone at lower temperature (269). Cyclic enones can be synthe-... 

Three important processes have evolved from Reppe s work. Vinylation, the formation of vinyl derivatives by reaction of such compounds as acids, glycols, and alcohols with acetylene, produces the important vinyl esters and vinyl ethers. Ethinylation is defined as the reaction of acetylene with the carbon atom of a reactant without loss of the triple bond. A major application of the ethinylation reaction is to aldehydes and ketones to give alkynols and alkyndiols—e.g., the reaction of acetylene with formaldehyde to give propargyl alcohol and butyn-2-diol-l,4. Carboxylation (also referred to as carbonylation), the reaction of acetylene with carbon monoxide in the presence of metal carbonyls, has been applied to the production of acrylic acid, acrylates, and hydroquinone. 

Reaction of acetylene and carbon monoxide with water in the presence of Fe(CO)5 yields hydroquinone. Although this reaction occurs stoichiometrically at 50-80 °C, the reaction becomes catalytic and a yield of up to 70 % is obtained under high CO pressure (600 700 atm) (eq (4)) [24]. 

A slow stream of acetylene passed with vigorous stirring into a mixture of ehloroacetie acid and yellow HgO, in the presence of a small amount of hydroquinone, at 50-55° for ca. 3 hrs. —> vinyl chloroaeetate. Y 42-49%. (R. H. Wiley, Org. Synth. 28, 94 (1948).)... 

M ethoxy acetylene Oxido compounds Ethylene oxide Tetrahydrofuran Dioxane Benzoin Glucose Hydroquinone CO... 

Reaction of various terminal alkynes using PdCl2 and CuCl2 in the presence of a base affords the alkynic esters 310 in satisfactory yields (path a) [122]. Carbonylation of terminal alkynes proceeds smoothly using Pd(OAc)2, hydroquinone and heteropolyacid (molybdovanadophosphate, NPMoV) in the presence of MeSOsH under oxygen at room temperature. Different products are obtained depending on the solvents. In MeOH, the acetylenic ester 311 was obtained (path a), but a-alkylmaleic anhydride 312 was obtained in dioxane (path c) [125]. 

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