Patent GB-677438-A (GB)
Title: Improvements in or relating to the manufacture of resinous products from dihydropyran derivatives
IPC: C08G61/12
Filed: 1949-09-08
Abstract: Resinous products suitable for use in the production of adhesives, coating compositions, modified drying oils, cast and moulded articles are obtained by condensing a dihydro-2-monoformyl pyran with an organic hydroxyl containing compound, other than methanol, in the presence of an acid catalyst.  The dihydropyran derivatives are of the general formula <FORM:0677438/IV (a)/1> where R is hydrogen, halogen or an open-chain hydrocarbon radical containing from 1-5 carbon atoms, as exemplified by: 2.5-dichloro-3.4 - dihydro - 1.2 - pyran - 2 - al; 3.4 - dihydro - 1.2 - pyran - 2 - al; 2.5 - diisopropyl - 3.4 - dihydro - 1.2 - pyran - 2 - al; 4 - butenyl - 3.4 - dihydro - 1.2 - pyran - 2 - al; 2.5 - dimethyl - 3.4 - dihydro - 1.2 - pyran - 2 - al; 5 - butyl - 3.4 - dihydro - 1.2 - pyran - 2 - al; 3.4 - diethyl - 3.4 - dihydro - 1.2 - pyran - 2 - al; 2.3.5 - triethyl - 3.4 - dihydro - 1.2 - pyran - 2 - al; 2.4.6 - trimethyl - 3.4 - dihydro - 1.2 - pyran - 2-al.  These dihydropyran derivatives may be prepared as described in U.S.A. Specifications 2,479,283 and 2,479,284.  Hydroxyl substituted organic compounds specified are: (1) monohydric aliphatic alcohols-ethyl, methyl, butyl, tert.-butyl, amyl, allyl, octyl, decyl, benzyl alcohols; pentadecanol, cyclopentanol, cyclohexanol, 2.4-diethyl cyclohexanol;  (2) polyhydric alcohols-glycols, glycerol, 2.4-butanediol, 2.4.6-heptane diol, 2.3-hexadienediol-4.5-polyvinyl alcohol, polyallyl alcohol, 1.5-cyclopentanediol, octane triol;  (3) polyhydric phenols-pyrocatechol, resorcinol, phloroglucinol, 1.3 - naphthalene - diol, 1.4.5.8-naphthalenetetrol;  (4) partial esters of polyhydric alcohols or phenols-glycerol monostearate, monohexoate, monophthalate, 2.4-butanediol monostearate, 1.5-cyclopentanediol monopalmitate; 1.2.5 - cyclohexanetriol diacetate, glycerol monolaurate, glycerol monoacetate, resorcinol monoacetate, phloroglucinol mono-oleate, pyrogallol dihexanoate, 1.3-naphthalenediol mono-octanoate, 1.4-naphthalenediol monocaproate; (5) partial ethers of polyhydric alcohols or phenols-glycol monopentyl-, glycerol monoethyl-, 2.4-butanediol, 1.2-cyclohexanetriol monoallyl-, resorcinol monophenyl-, phloroglucinol monohexyl-, pyrogallol monoallylethers, ethyl cellulose;  (6) ether-esters-glycerol monobutyl ether monostearate, hexanetriol monoacetyl ether monoacetate, phloroglucinol monoethyl ether monostearate;  (7) glycerides of drying oil acids-glycerol dioleate, linoleate, linolenate, senecioate, dilinoleate, disorbate, dioctenate, dicasodienate, pentacosadienoate.  From 5-0.5 and preferably 2-0.5 hydroxyl groups are used per formyl group. Catalysts specified include boric, acetic, butyric, benzoic, p-toluenesulphonic, oxalic, malonic, succinic, pimelic and the usual inorganic acids.  Temperatures may vary from 0-250 DEG  C. and the reaction may be carried out in presence of diluents, e.g. benzene, toluene, xylene, cyclohexane, ethyl ether.  The resinous products vary from viscous liquids to semi-solids and may be cured to insoluble products by heating or subjection to light in the presence of catalysts, e.g. acids and peroxides such as benzoyl, acetyl, sodium or barium peroxides, peracetic acid or perphthalic acid. Adjuvants which may be added comprise asbestos, sand, clay, talc, mica, wood flour, cotton, pitch, asphalt, shellac, copal, camphor, naphthalene, anthracene, dioctyl phthalate, dibutyl phthalate, tricresyl phosphates; organic plastics, e.g. protein plastics, phenol aldehyde resins, vinyl polymers.  In examples: (1) 28 parts 3.4-dihydro-1.2-pyran-2-al are reacted with 16.5 parts resorcinol in presence of oxalic acid at 65 DEG  C.; (2) as in (1) with the addition of glycerol; (3) with glycerol alone, oxalic, phosphoric, tartaric acids being used as catalysts; (4) with ethylene glycol; (5) with hexane triol; (6) with trimethylol propane; (7) with pentaerythritol; (8) with glycerol p  and polyvinyl alcohol; (9) with glycerol n-decyl ether; (10) with castor oil; (11) with glycerol and ethyl cellulose; (12) with glycerol n-decyl ether and glycerol; (13) with linseed monoglyceride; (14) with linseed diglyceride; (15) with linseed diglyceride and linseed monoglyceride; (16) 10 parts of 2.5-dichloro-3.4-dihydro-1.2-pyran-2-al were heated for 72 hours at 65 DEG  C. with 8 parts glycerol in presence of oxalic acid; (17) 45 parts 2-butyl-3.4-dihydro-1.2-pyran-2-al were heated at 65 DEG  C. for 100 hours with 25 parts glycerol n-decyl ether stearate.  The Specification as open to inspection under Sect. 91 relates to the condensation of dihydropyran carboxaldehydes in general; the following being specifically referred to: 2-methyl-3.4-dihydro-1.2-pyran-3-carboxaldehyde; 2.5-dimethyl - 3.4 - dihydro - 1.2 - pyran - 4 - carboxaldehyde; 2.5 - dimethyl - 3.4 - dihydro - 1.2 - pyran - 3.2 - butyl - 3.4 - dihydro - 1.2 - pyran - 4-, 4 - methyl - 3.4 - dihydro - 1.2 - pyran - 5-, 2 - butyl - 3.4 - dihydro - 1.2 - pyran - 6-, 3.5 - dibromo - 3.4 - dihydro - 1.2 - pyran - 3 - carboxaldehydes. Further, according to example 13 (Cancelled), 3.4-dihydro-1.2-pyran-2-al is reacted in presence of 10 parts aqueous 0.02 N sulphuric acid at 65 DEG  C. for 12 hours to give a hard-surfaced resin.  Inorganic hydroxyl-containing compounds and methanol are included in the scope of the Specification as open to inspection.  This subject-matter does not appear in the Specification as accepted.