Patent GB-653058-A (GB)
Title: A process for preparing dihydric heterocyclic alcohols and esters thereof
IPC: C07D309/10
Filed: 1948-01-23
Abstract: Cyclic heterocyclic alcohols of the formula:  <FORM:0653058/IV (a)/1> where R is hydrogen or hydrocarbon, are esterified with dicarboxylic acids such as oxalic, succinic, maleic, glutaric, phthalic, adipic, pimelic, sebacic, diglycollic and diphenic acids, to produce alkyd-resins.  Heat-convertible alkyd resins are also prepared by esterification of these alcohols either alone or with polyhydric alcohols, e.g. glycerol, with polycarboxylic acids, e.g. tricarballylic, citric, and aconitic acids. Plasticizers and lubricants for resinous moulding compositions are prepared by exterification of the above alcohol with non-drying aliphatic monocarboxylic acids containing 12-20 carbon atoms or monocarboxylic resin acids such as stearic, palmitic, ricinoleic, myristic, arachidic, lauric, copal resin, rosin and modified rosin acids.  The Specification as open to inspection under Sect. 91 comprises also the case where the group R is substituted by amino, hydroxy or halogen groups.  This subject-matter does not appear in the Specification as accepted.ALSO:4 - Hydroxy - 3 - hydroxymethyltetra hydropyrans of formula <FORM:0653058/IV (b)/1> where the R's are the same or different and are hydrogen or hydrocarbon, or esters thereof, are prepared by treating an a  : b -unsaturated aldehyde having a hydrogen atom attached to the a  carbon atom with water in the presence of a strong mineral acid, e.g. sulphuric acid, as hydration catalyst at a temperature of up to 35 DEG  C., and then subjecting the crude hydration mixture, or a non-aqueous fraction separated therefrom, to catalytic hydrogenation above 100 DEG  C. but not above 200 DEG  C. (preferably not above 150 DEG  C.) and esterifying the product if required.  The groups R may be alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl alkaryl or aralkyl.  Preferred conditions are the use of a pH of from 0.5 to 2.5 and a high concentration of aldehyde in the hydration step, and of high pressures, e.g. 500-5000 pounds per square inch and an inert solvent in the hydrogenation. By-products in the hydrogenation are the alcohols CHR2.CH2.CH2OH formed from unreacted aldehyde. The heterocyclic alcohols may be esterified and with mild conditions, only the primary hydroxy group reacts.  Acids used include mono- and polycarboxylic acids and their reactive derivatives.  Specified acids comprise acrylic, crotonic, proparglylic, a -chloroacrylic, a  : b -dichlorocrotonic; higher aliphatic acids such as stearic, ricinoleic, lauric, and rosin acids; drying oil acids such oleic, linoleric and eleostearic; dicarboxylic acids such as oxalic, phthalic or adipic.  In the examples acrolein is hydrated, water removed from the product by distillation, and the residue hydrogenated in the presence of Raney nickel to give 4-hydroxy-3-hydroxy-methyltetrahydropyran.  The Specification as open to inspection under Sect. 91 comprises also the use of initial unsaturated aldehyde which may be substituted by amino, hydroxy, or halide groups.  In addition, the hydration and hydrogenation stages are not limited with regard to temperature.  This subject-matter does not appear in the Specification as accepted.