Patent GB-902801-A (GB)
Title: Cyclic organophosphorus compounds and method of preparing same
IPC: C07F9/6571
Filed: 1959-10-08
Abstract: 2,4,6-Trisecondary alkyl 1,3-dioxa-5-phosphacyclohexanes having the general formula:  <FORM:0902801/III/1> in which R1-R6 are C1-C10 alkyl groups, Y is a radical selected from PH, PRa, P(O)Ra, P(O)OH, P(O)ORb, P(O)OM, P.C(O)NH.Rc, PX and P(O)X, Ra is a substituted or unsubstituted saturated or unsaturated aliphatic hydrocarbon radical, substituted or unsubstituted aryl radical, or a saturated or unsaturated substituted or unsubstituted alicyclic hydrocarbon radical, specified substituents being halogen, carbamyl, cyano,amino,hydroxyl,acyloxy,carbalkoxy,carboxy,alkoxy,aryl and aryloxy,Rb is a hydrocarbon radical, M is a mono- or poly-valent metal, Rc is a substituted or unsubstituted hydrocarbon radical and X is halogen, e.g. Cl or Br, may be used as gasoline additives to prevent preignition caused by, e.g. lead deposits.  In an example up to 5 ml. of 2, 4, 6-tri-isopropyl, 1,3-dioxa-5-phosphacyclohexane is added to one gallon of gasoline.ALSO:The invention comprises 2,4,6-trisecondary-alkyl-1,3-dioxa-5-phosphacyclohexanes having the formula:- <FORM:0902801/IV (b)/1> wherein R1 to R6 are C1-C10 alkyl groups, Y is a radical selected from PH, PRa, P(O)Ra, P(O)OH, P(O)ORb, P(O)OM, P.C(O)NHRc, PX and P(O)X, Ra in the radicals PRa and P(O)Ra being a substituted or unsubstituted, saturated or unsaturated branched or straight chain aliphatic hydrocarbon radical, a substituted or unsubstituted aryl radical, a saturated or unsaturated substituted or unsubstituted alicyclic hydrocarbon radical, said substituted radicals carrying substituents such as halogen, carbamyl, cyano, amino, hydroxyl, acyloxy, carbalkoxy, carboxy, alkoxy, aryl and aryloxy; P(O)Rb represents the ester group derived from P(O)OH, Rb being a hydrocarbon radical e.g. methyl, ethyl, octyl or phenyl; P(O)OM represents the salt group derived from P(O)OH, M being a mono- or poly-valent metal e.g. Na, K, Ba, Ca, Zn, or Hg; P.C(O)NH.Rc represents the carbamyl derivatives of the above general formula, Rc being a substituted or unsubstituted hydrocarbon radical e.g. phenyl, chlorophenyl, butyl, or chloroethyl; and PX and P(O)X represent the halogenated derivatives of the above general formula, X being a halogen atom e.g. Cl or Br.  They may be obtained by (1) reacting at least one alkyl aldehyde Re-CH(Rd)-CHO (III) or a derivative capable of producing said aldehyde under the reaction conditions wherein Rd and Re are alkyl groups having the same number of carbon atoms as R1 to R6 with phosphine in the presence of an aqueous mineral acid solution to form a compound of the general formula:  <FORM:0902801/IV (b)/2> (2) and then according to the product desired carrying out one of the following reactions on the product of formula II:- (a) oxidising by a method of oxidation known to convert a PH group to a P(O)OH group, e.g. with air, to produce the corresponding phosphinic acid in which Y in formula I is P(O)OH and if desired then forming the ester or salt of the phosphinic acid compound of formula I wherein Y is P(O)ORb or P(O)OM; (b) reacting with an isocyanate RcNCO to produce the compound in which Y is P.C(O)NH.Rc; (c) condensing with an appropriate olefinic compound e.g. 1-octene to produce the compound in which Y is PRa and, if desired, oxidising the latter by a method known to convert a PRa group to a P(O)Ra group to obtain the compound in which Y is P(O)Ra wherein Ra is as defined above except that Ra in this procedure only (reaction with olefin and subsequent oxidation, if desired,) is not an aryl group having one of its aromatic carbon atoms attached to phosphorus, (d) treating the product of formula II or the phosphinic acid produced in step (a) with a halogenating agent to produce the compound of formula I in which Y is PX or P(O)X and, if desired, reacting the compound of formula I in which Y is PX, thus produced, with a Grignard reagent RaMgX to produce the compound of formula I in which Y is PRa and further if desired oxidising the latter by a method of oxidation (e.g. reaction with H2O2) known to convert a PRa group to a P(O)Ra group wherein Ra is as defined for formula I above; (3) and further, if desired, treating the compounds of formula I as produced in any one of the above steps (1) and (2) with a different aldehyde of formula III or a derivative capable of producing said aldehyde under the reaction conditions to exchange the R1 to R6 groups for the C1 to C10 alkyl groups of the said different aldehyde.  The product of formula II may be converted to the PCl compound by treatment with COCl2 and the phosphinic acid compound wherein Y is P(O)(OH) may be converted to the P(O)Cl compound by treatment with SOCl2.  The aqueous mineral acid used in step (1) may suitably be HCl, HBr, HI, H2SO4 or H3PO4 and particularly suitable aldehydes for use in this step are isobutyraldehyde, 2-ethylhexaldehyde, 2-ethylbutyraldehyde, 2-methyloctaldehyde, 2-propylpentaldehyde and 2-methylheptaldehyde. Generally, at least 3 molar equivalents of aldehyde should be used per molar equivalent of phosphine.  The aldehyde may be used in the form of its acetal derivative.  Step 2 (c) may be effected in the presence of an initiator e.g. 2,21-azo-bisisobutyronitrile and the reaction in step (3) may be carried out in the presence of an aqueous mineral acid. The reactions are generally carried out at between about 0 DEG C. to 80 DEG C.  Several examples are given.  The products are useful as gasoline additives (see Group III).