Hydroquinone methyl ether

Chemical Reactivity - Reactivity with Water No reaction Reactivity with Common Materials No reaction Stability During Transport Stabie Neutralizing Agents for Acids and Caustics Not pertinent Polymerization Heat, oxidizing agents, and uitraviolet light may cause polymerization Inhibitor of Polymerization Hydroquinone, 22 - 65 ppm hydroquinone methyl ether, 22 -120 ppm dimethyl tert-butylphenol, 45 - 65 ppm. 

Physical Form. Colorless liquid with acrid odor commercial form contains hydroquinone (lOOOppm) or hydroquinone methyl ether (15 or 2 00 ppm) to prevent polymerization... 

TABLE 10.2 Addition Rate Constants kj of Various Radicals to Monomers Reaction Rate Constants kr of These Radicals with Oxygen, an Amine, a Stabilizer (HQME Hydroquinone-Methyl Ether) and a Spin Trap (TEMPO 2,2,6,6 Tetramethylpiperidine N-Oxyl). 

Most organohalogens produced by fungi have an aromatic structure important groups include the chlorinated anisyl metabolites, drosophilins, and other chlorinated hydroquinone methyl ethers, chlorinated sesquiterpenens, chlorinated anthraquinones and strobulirins [72]. 

Hydroquinone methyl ether. See Hydroquinone monomethyl ether... 

CAS 150-76-5 EINECS/ELINCS 205-769-8 Synonyms p-Guaiacol HA HQMEE Hydroquinone methyl ether 4-Hy-droxyanisole p-Hydroxyanisole MEHQ 4-Methoxyphenol p-Methoxyphenol MME Monomethyl ether of hydroquinone Phenol, 4-metho) -... 

Uses In antifoams for waterborne coatings and adhesives Regulatory Canada DSL Trade Names Containing Nalco 2314 Hydroquinone methyl ether. See Hydroquinone monomethyl ether Hydroquinone monomethyl ether CAS 150-76-5 EINECS/ELINCS 205-769-8... 

The polymeric products can be made to vary widely in physical properties through controlled variation in the ratios of monomers employed in thek preparation, cross-linking, and control of molecular weight. They share common quaHties of high resistance to chemical and environmental attack, excellent clarity, and attractive strength properties (see Acrylic ester polymers). In addition to acryHc acid itself, methyl, ethyl, butyl, isobutyl, and 2-ethylhexyl acrylates are manufactured on a large scale and are available in better than 98—99% purity (4). They usually contain 10—200 ppm of hydroquinone monomethyl ether as polymerization inhibitor. 

Polymerization inhibitors are key additives which prevent premature gelation of the adhesive. The foimulator must carefully balance shelf stability and the required cure on demand. Due to its high propagation rate, MMA is difficult to inhibit. Some comments on specific inhibitors follow. The most common inhibitor to be found in component monomers is 4-methoxyphenol, which is also called the methyl ether of hydroquinone. This inhibitor is effective only in the presence of oxygen. A mechanism has been proposed, and is illustrated in Scheme 13 [128]. 

Acrylic Acid, CH2CHCOOH Free Radical Formers such as OH Ion Acrylic Acid Vapor 6000 kg/cm2 >75 Inhibitor—Methyl Ether of Hydroquinone-200ppm Storage in a cool, well ventilated area 18.5 429 Heterogeneous Free-Radical with a catalyst such as Azodiisobutyro-nitrile... 

Methyl Methacrylate CH2=C(CH3)COOCH3 Impure Methyl-Methacrylate Vap in Air 2.1 to 12.5% > Ambient > 110 Inhibitor-Hydroquinone or Methyl Ether of Hydro-quinone. Shield from light avoid sparks. Store in cool place 13.3-13.8 421 Self-polymerizing initiated by visible light at 20 to 40°... 

Styrene C6H5CH=CH2. Alkali Peroxy compds Vap in Air 1.1 to 6.1% > Ambient > Ambient Inhibitor—Methyl Ether of Hydroquinone—10-15 ppm, Phenol Subst-Hydroxyl Amine, etc. Store below 70°F. Avoid sparks in. vap/air mixt 17.4-17.8 490 Soln polymerization catalyzed with w or Ti tetrachloride. Also self polymerization... 

Vinyl Acetate CH3COOCH=CH2 OH compds, HCN, Halides, Halogens, Mer-cap tans, Amine, Silanes Oxygen Vap in Air 2.6 to 13.4% > Ambient > Ambient Inhibitor—Methyl Ether of Hydroquinone or 3-5ppm Diphenylamine. Store in a dry, cool place shield from light impurities 20.9-21.5 402 427 Free-radical polymerization initiated by Benzoyl Peroxide... 

HjC ° ° CH3 2-(2-ominocorbonyl-oxy-1 -methoxyethyl)-5-methyl hydroquinone dimethyl ether... 

CiiHijNO, 3SS4J-4J-7) see Carboquone 2-(2-aminocarbonyloxy-l-methoxyethyl)-S-methyl-hydroquinone dimethyl ether (CjjHiijNOj 38843-63-9) see Carboquone [6U-[6a,7a,7(iJ )])-3-[[(aminocarbonyl)oxyJmethyl]-7-[[5-carboxy-S-[[(4-methylphenyl)sulfonyl]amino]-l-oxo-pentyl]amino]-7-methoxy-8-oxo-5-thia-l-azabicy-clo[4.2.01oct-2-ene-2-carboxylic acid compd. with A-cyclohexylcyclohexanamine (1 1)... 

Standard on Explosion Prevention Systems, National Fire Protection Association, 2002). For example, methyl acrylate and ethyl acrylate are commonly stabilized with hydroquinone monomethyl ether. Industry guidance recommends a minimum concentration of 5 vol % 02 in the atmosphere above the acrylate to prevent polymerization (Intercompany Committee for the Safety and Handling of Acrylic Monomers, Acrylate Esters, A Summary of Safety ana Handling, 3d ed., 2002). 

It should be noted that one of these diols, the hydroquinone, did not provide any oligomer in the first step. This was due to the formation of the quinone structure which made it impossible to use hydroquinone directly in the substitution reaction. An alternate method was used to overcome this problem which involved the use of 4-methoxyphenol to obtain the sulfone product, followed by cleavage of the methyl ether to the diol (VIII) with boron tribromide. This set of reactions is outlined in Figure 5. 

Methyl acrylate, 99S (stabilized with 200 ppm hydroquinone monoraethyl ether), propionaldehyde 97%, and l,4-diazabicyclo[2.2.2]octane were purchased from the Aldrich Chemical Company, Inc. and used as supplied. 

As normally supplied, acrylic esters are inhibited to enhance the shelf life. Aside from dissolved oxygen, inhibitors that are deliberately added include phenolic compounds such as hydroquinone (HQ) and p-methoxyphenol (MEHQ, i.e., methyl ether of hydroquinone ). These inhibitors are usually present in concentrations of 50 to 100 parts per million (ppm) by weight. Oxidation products of the phenolic inhibitors may also be present. 

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