CA1056393A - Phosphate esters - Google Patents

Abstract

ABSTRACT
Phosphate esters having the formula wherein A has the structural formula and B has the structural formula

Description

BACKGROUND OF TRE INVENrION
Field_of the Invention This invention relates to novel phosphate esters prepared from polycyclic phosphorohalidites. These esters, which are use~ul as flame retardants especial-ly ~or rlgid polyurethane ~oam~, have the ~ormula:
RO~(A)m(B)n~H wherein A has the structural formula ~ O
" "

-- P- O - ~c O- PR2Rl H O O -_ and B has the structural formula O -/ ~ ~--O-P-ORl _ _ p ~ ~ oR2 _ wherein R~ Rl, and R2 are the sAme or dlfferent and are alkyl radlcal~, ~nd m and n are integer~ from O to about 4, the sum of m plu8 n being from one to ~bout four. It is understood that structures A and B are randonmly dlstributed within the~e oiigomerlc compounds.

Description of the Prior Art Bli2nyuk et ~1., Zh. Ob~heh. Khim, 34, p. 1169-70 (1960), teach react~ng PC13 with an excess o~
alcohol ln the pre~ence of chlorine to produce PO(OR)3.
Frank et al. J. Org. Chem., 31, p. 872-5 (1966), converted ~lmple trialk~l pho~phltes (RO)3P to the

-2-

3 1056393 corresponding pho~phate~ (RO)3PO in a slmllar fashionl Neither of the above references however disclose the conversion of polycycllc phosphorohalidites to the phosphate esters of thi~ lnvention.

SUMMARY OF THE _NVENTION
It is an ob~ect of thls lnvention to provide new phosphate esters. It is a ~urther obJect of this invention to present a process for preparing such phosphate e~ters. I~'is another ob~ect of thi~ inven-tion to prepare flame resi~tant polymers with the useof said phosphate esters, and it is still another ob~ect of this invention to prepare ilame retardant polyurethane and polyester polymers, e~pecially rlgid polyurethane foams with the lncluslon thereln o~ the co-reactive phosphate esters.

~ rDON OF THE PREFERRED EMBODIYENTS
Polycycllc phosphorohalidltes are used for the preparation of the phosphate ester~ of this lnventlon.
These phosphorohalldites precursor~ have the general formula tC5H804P2 )XUY~, whereln the substltuent~ X
~nd Y ma~ either be halogen or alkoxy radical~ as described herelnafter.
The phosphate esters of this invention are prepared from the above pho~phorohalidites resulting in the new compounds of the general formula R *(A)m (B)n-3H~ wherein A has the ~tructural io~mula --,0, ,0, -- ''' tOR2~ oR2 , -3-.. , , . . ~, . .. . . ....

-4- 1056393 and B has the ~tructural formula L ~~ O ~

whereln R, Rl and R2 may be s~me or different and are selected from primary alkyl radicals having from 1 to about 6 carbon atoms and haloalkyl or hydroxy-alkyl radical~ having from 2 to 6 carbon atom~.
These radicals may be elther linear or branched.
Examples of ~uch radlcals, but not ln limitation here-of, include methyl, ethyl, propyl, n-butyl, lsobutyl, n-pentyl, 2-methylbutyl, 3-methyl-butyl, neopentyl, n-hexyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 2-chloroethyl, 2-bromoethyl, 2- or 3-chlorpropyl, 2-or 3-bromopropyl, 2,3-dlrbomopropyl, 2,3-dichloro-propyl, 4-chlorobutyl, 5-chloropentyl, 6-chlorohexyl, 2-hydroxyethyl, 3-hydroxypropyl, 4-hydroxybutyl,

5-hydroxypentyl and 6-hydroxyhexyl.
The polycycllc phosphorohalldite precur~or~ are known compounds of the general formula (C5H804P2)~ Yv whereln X 18 bromine or prefera~ly chlorlne, Y i8 an oR3 group wherein R3 1B an alkyl or halo~lkyl radlcal selected ~rom the ~ame groupa QB R above~ but not a hydroxyalkyl radlcal, u and v each have the values of 0, 1 or 2,and the ~um o~ u plU8 V i8 2. These pre-cursors may al80 be represented by the structurAl formulae Z-p~ P-Z

and / o ~ 2 Z2 which-are isomers and wherein Z ha~ the meanlngs o~
X or Y as defined above. Although the polycylic precursors wherein the ~ubstituent groups (X) are halogen are called phosphorohalidltes, and wherein the substituent gr~ups (Y) are oR3 are usually named phosphltes, the latter compounds shall be included under the general term phoRphorohalidites ~or the purpo~e of this disclosure.
Polycyclic phosphorohalldites may be prepared from phosphorus trlhalldes such as PC~3 or PBr3 and and pentaerythrltol according to the method described by H. J Lucas et al. J.A.C S Vol. 72, p. 491-497 (1950) The conversion from halogen to oR3 substitution may be made in accordance with U.S. Patent 2,961,454 (aould et al.). It has been found that the ~re~hly prepared spirocyc~ic or blcycllc compound~, ~ith tlme, isomerize to form an equilibrium mixture containing both structural isomer~. Either lsomer or a mixture thereo~
i~ sultable ~or the preparation o~ the in~entlve e~ters.
In view of the phosphorohalldites being ~olids they are conveniently prepared in the presence of an inert solvent. Subsequent preparation o~ the phosphlte esters o~ thi~ lnvention may be conveniently carried out using the phosphorohalidite solution thus obtained wlthout .: . . .

-6- ~056393 prior recovery of the precursor. It ls advantageous to choose a solvent wherein not only the precur~or but also the ester i6 soluble, thus chlorinated hydro-carbon~ such as carbon tetrachloride, chloroform, ethylene dichloride, methylene dlchlorlde, and the like are especially sultable. The preferred solvent is ethylene dichloride. Since the spirocycllc pre-cur~or ls more soluble in the above mentioned solvents, it i~ the preferred form ~or use herein.
The compounds of this lnvention are prepared by the addition of a polycyclic phosphorohalldite to a primary allphatic alcohol ln the presence o~ chlorine.
Sald alcohols have the general formula HOQ, wherein Q
has the same meAnings as R,Rl and R2 defined above.
The use of ~econdary or tertiary alcohol~ for the making of slmilar products accordlng to the process of this invention while possible i~ not recommended because of the tendency of such alcohols to form hypo-~ halides in the presence o~ C12. Hypohalide~ may de-compose rapidly, even explosively, at ambient temperatures, When preparing the esters of thi~ invention the ratio of alcohol must be controlled within certaln llmlts in order to prevent undeslrable side reActions.
If the ratio is too low, Arbuzov type re~rrangements may take place; i~ the ratio is too high, pentaerythrltol and non-polycyclic or polymeric trlalkyl phosphates are produced. Therefore, the molar ratlo of HOQ to X plu~ Y
~hould be equal to ~rom (au + ~:1 10(2u+v):1 ~aid ratio not exceeding a value of 20:1.
If u equals 2 and v equal~ 0, the pre~erred

-7- 1056393 molar ratlo of HOQ to X+Y ha~ a value of ~rom 5 to 15, most pre~erably from 8 to 12. If u equals 0 and v i6 2, the pre~erred molar ratio range may be from 2 to 7, the mo~t pre~erred ratio being from 3 to 5. Withln the~e limlt~, the ratlo o~ the reactant~ may be varied a~ desired to produce pho~phate esters havlng a wlde range of hydroxyl number~. For instance, lf X i8 ~-chlorine, the alcohol iB ethanol and the rQtio i8 15, ester~ having an OH number of about 190-200 are produced, while a ratio o~ 8 leads to a product wlth an OH number -o~ about 110-130. If X is chlorlne, the alcohol iB 2-chloroethanol~ and the ratlo i8 6, the resultant pro-duct has an OH number of about 120, while at a ratio o~
5 an OH number o~ about 90 resulte.
While agitating the reaction mixture, the polyc~cllc pho~phorohalidlte (dlluted wlth an approprl~te~
inert 601vent i~ BO deslred) 1B addod contlnuouBly or ` ;~
incrementably to the alcohol. ~he ~lcohol may option~llg ~
be diluted wlth an inert organlc eolvent in whlch the ~ ;
reactant~ and the reeultant pho~phate esters are ~oluble.
Simultaneouely, but separately ko the ~ddition of the phosphorohalidite, chlorine i~ charged to the alcohol. The rate of ~ddition Or the two ingredients ie maint~lned at a molar ratlo of h~logen to phoephoro-halldite of at lea~t 2:1. Usually a ~light e~cess Or halogen is used, preferably not exceeding 10 ~ole p~r-cent. A convenient way to malntain the proper con-centr~tlon of chlbrine durihg th~ r~actlon and to en8ure ` tha~ chlorlne 1~ in a sligh~ excesa~ ic Oy monltoring the potentlaI o~ the reaction medlum wlth ~ standar~

..;
~, ' , . .

-8- ~056393 potentiometer fitted with a redox probe con~isting of a platlnum measuring probe wlth a standard calomel reference electrode. This operation is carried out by selecting a potential which is below that ob~erved for the reaction medium, e.g. the solvent or alcohol or mixtures thereof saturated with chlorine In the case of a potentiometer with a scale from zero to 1400 mv, for example, this operation is carried out at a potential below 1400 mv, usually in the range from 500 mv to 900 mv. An excess of chlorine may al80 be followed visually by the appearance of a greenlsh color in the reaction mass. The reaction iB completed when, after addition of all of the polycyclic phos-phorohalldite, the resultlng solution maintalns a permanent greenish color and no further uptake of halogen is observed.
Alternatively, when Y is oR3 and v le 2, the polycycllc startlng material may be dlssolved ln the alcohol using an appropriate solvent lf de~ired such as ethylene dlchlorlde, and then sub~equently treated wlth chlorine until the reaction i8 complete.
The proce~s of thls inventlon i8 exothermlc and requlres cooling to maintain a temperature of from about -20C to about 80C, prefersbly 20C to 40C.
~5 Upon the completion of the reactlon~ the phosphate esters may be recovered by stripplng the 801u-tion under vacuum at about 30-50C to remove the bulk of the hydrogen chloride produced durlng the reaction. ~he solution 1B then neutralized by any conventional method, such as by the addition of sodium bicarbonate~ aqueous '' ,''.

- . - - ~ . . - .. .. - . ~ . . . .. . ~ .

9 1056393 sodium or potassium hydroxide, or an alcoholate salt.
Neutralization may also be performed by using an epoxide such as ethylene or propylene oxlde. Alternatively, the reaction mixture may first be neutrallzed and then stripped as described above.
The neutralized mlxture ls then sub~ected to vacuum distillation to remove any residual solvent or alcohol as well as any volatile by-product~ such as haloalkanes or chlorohydrins. The phosphate ester ls then recovered as the dlstillatlon resldue.

Example I
Preparation of 3,9-Dichloro-2,4,8,10-tetraoxa-3,9-di-~osphaspl o~ 5~? 5~ unde ane _ This polycycllc phosphorochloridite precursor is prepared ln the following manner: To a 2-liter, 3-necked round bottom fla~k equipped with a condenser, a stirrer, a thermometer, a dropplng funnel and a nitro-gen inlet tube, is added PC13 (280,0 g, 2.04 moles) dropwise to a stlrred suspenslon o~ pentaerythrltol (136.0 g, 1.0 mole) in dichloroethane (240 ml). The reaction mixture is kept at 35-50C by means Or a water bath. During the additlon the system iB kept under a gentle nitrogen sweep to facilitate the removal of the HCl formed. When the PC13 addition ls completed, the temperature of the reactlon mixture 18 slowly raised to reflux o~er about a one hour period. The mlxture 18 then kept under reflux, using a vigorous nitrogen sweep, until a homogeneous solution is obtained, i.e. about one to two hours. Trace amounts of white precipitate may ~-separate from the reaction ~olution upon cooling to room g_ - , - . . . . . . . .
, . . . . .
-.

-10-temperature. This small amount of preclpitate, conæist-ing mostly of pentaerythritol, is removed by filtration.
The filtrate contains the desired product, 3,9-dlchloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro~5.5~ undecane, and is essentially free of by-products. The phosphoro-chloridite precursor thus obtained is used ln the sub-sequent reactions without further puri~ication.

Example II
Methyl Phosphate Ester Thls example repreRents the general procedure for the preparation of the compounds of this lnvention by oxidation Or a phosphorochlorldite wlth chlorlne ln presence of an alcohol.
Methanol (240 g, 7.5 moles) i3 stirred and cool-ed to 5 to 10C by means of an acetone-lce bath ln a reaction vessel fltted with a thermometer, an addltlon funnel, and a gas lnlet tube connected to a chlorlne gas cylinder. Chlorine (2 moles) and the phosphorochlorldlte (1 mole~ Or Example I are added slmultaneously to the methanol malntainlng a sllght chlorlne exce8s, a~
evldenced by the greenl~h color Or the reaction medium.
Durlng the additlon, the reactlon mixture 18 maintalned at about 25 to 35C by means Or the acetone-lce bath as well as by controlllng the rates Or addltion o~ the re-actants. When the addltlon Or pho~phorochloridlte 18 completed, the resultlng greenlsh solutlon i8 distllled under 10-20 mm Hg pressure at about 30-50C in order to remove most of the HCl formed durlng the reactlon. The re~ldual acidic solution i8 then treated with propylene oxide at 40-60C untll neutral to moist litmus paper.

-Low boiling materials are then f~rther removed from the reaction solution by distlllation under 10-20 mm. Hg and ~ -subsequently 0.5 mm. Hg at about 100C. The re~idue ls the methyl phoæphate ester, a clear fluld oily material.
Analysis: 12.5% P: o.8% Cl; 0H~203 In Examples III to X incluslve, the æpiro-cyclic compound described in and prepared essentially according to Example I is used exclu~ively.

ExalQle III
Methyl Pho ~ r The procedure of Example II i8 repeated except that 15 moles of methanol are placed ln the reaction vessel, the overall methanol to phosphorochloridlte mole ratio belng 15.
Analysls: 16.4% P; 0.5% Cl: OH #287 Example IV
Ethyl Phosphate Ester The procedure o~ Example II 1~ repeated except that 15 moles o~ ethanol are u~ed in place Or the methanol.
Th0 mol0 ratio o~ ethanol to phosphorochlorldlte belng 15.
The resultant product i8 a clear ~luid oll.
Analysls: 14.7% P: 0.4~ Cl; OH #19o Example V
Ethyl Pho3phate Ester The procedure of Example IV i8 repeated except that 8 moles-of ethanol are u~ed. The o~erall molar ratio of alcohol to phosphorochloridlte belng 8. The product ls a clear fluid oil.
Analysis: 14.6~ P; 0.7% Cl; OH #130 ~056393 Example VI
n-Butyl Phosphate Ester The procedure of Example II is repeated except that methanol is replaced by n-butanol, and the molar ratio of n-butanol to the phosphorochlorldite employed is 7Ø The product is a white w~xy solid.
Analysis: 13.6% P, OH#105 Example VII
2-ChloroethyI Phospha e Ester The procedure of Example II is repeated except that methanol is replaced by 2-chloroethanol, and the ratio of 2-chloroethanol to the phosphorochloridlte em-ployed is 4.5. The product obtained is a clear oll.
Analysis: 13.8% P; 19.8% Cl; OH #91 Example VIII
2,3 Dibrom propyl Phos~hate Ester The procedure of Example II 18 repeated except that methanol is replaced by 2,3-dibromopropanol at a molar ratio of 2.,3-dibromopropanol to the phosphoro-chlorldlte of 6. The resultant product is a dark tan viscous oil.
Analysls: 7. ~ P; 56.2~ Br; 1.7~ Cl; OH #76 Example IX
2-Hydr_xyethyl Phosphate Ester The procedure of E~ample II ls repeated except that methanol is replaced by ethylene glycol at a molar ratlo of ethylene glycol to the phosphorochlorldlte of 6.
The product is a clear oil.
Analysi~: 11.9~ P; OH #432 . ~

Example X
3-Hydrox~ropyl Phosphate Ester The procedure o~ Example II is repeated except 1,3-propaned~ol is used instead of methanol. A 4 to 1 molar ratio of the alcohol to phosphorochloridite i8 maintained. The product is an oll.
Analysis: 10.4~ P, OH #363 Example XI
2-Chlor ethyl_Phosphate Ester This example represents an alternate procedure for the preparation o~ the phosphate esters of this in-vention by chlorinatlon of a spirocyclic pho~phite where-in Y is a 2-chloroethoxy group and v is 2 ln the presence o~ an alcohol. The common lntermediate, the phosphoro-chloridite, is prepared as descrlbed ln Example I, using PC13 (280 g~ 2.04 mole) and pentaerythritol (136 1.O
mole) in dlchloroethane (240 ml.) as the solvent. The resulting solution is treated with ethylene oxide over a ;~perlod of about 2 1/2 hours at about 50C ln presence of TlC14 (5 drops) untll neutral to moist litmu~ paper.
The resultlng solutlon, now cont~ining the phosphlte, 3,~-bis(2-chloroethoxy)-2,4,8,10-tetraoxa-3,9-dlphospha-spiro ~5.5~ undecane, 18 dlluted wlth 2-chloroethanol (161 g, 2 moles) and treated wlth chlorine gas untll the solution mQintains a sllghtly green color, indicatlng that substantlally all of the phosphlte has reacted.
During oxidation, cooling wlth an acetone-lce bath 1 requlred to keep the temperature at about 25C. The reactlon ~olutlon ls neutralized wlth propylene oxide and concentrated first under 10-20mm Hg presgure and then under ..... .. . - :

0.3mm Hg pressure at about 100C pot temperature. The product is a cle~r oil.
Analysis: 14.9% P: 20.1% Cl; OH #70 Example XII
_ ._ Preparation of Dichloro (2,6,7-trioxa-1-phos-phabicyclo ~ .2]oct-4-yl)methyl phosphite. _ _ _ . . ., _ . _ . _ . _ _ _ This bicyclic precursor is prepared as ~ollows: -a solution of phosphorus trichloride (gl~og.~ o.66 mole) and 4-hydroxymethyl-2,6,7-trioxa-pho~phabicyclo~2.2.2]
octane [36.0g., 0.20 mole; prepared accordlng to the pro-cedure descrlbed by W.S~ Wadsworth et al., J.R.C.S,, 84, p. 615 (1962~in chloro~orm (200 ml) is stlrred at room temperature for about 3 hours and then kept at reflux-ing temperature for one hour. The product separates ~rom solution as white crystals. It i8 separated by flltra-tion, washed with an excess of carbon tetrachlorlde and dried ln air. The product has a melting range o~
118-120C.
Analysis: 23.7%P; theory 23.4~P
~ le XIII
Eth~l Pho~Rhate Ester _ . . .. _.. ~_ ._ . _ .. _ This example lllu~trate~ the preparation of the phosphate ester of this lnvention from the bicycllc phosphorohalidlte of Example XII uslng the procedure as descrlbed ln Example II except that methanol i8 replaced by ethanol. The mole ratlo of ethanol (62.5g) to the ~ ;
blcyclic pho~phorochlorldlte (30g, 0.113 moles ln 75 nil of chloroform) la 12. A clear fluld oll 18 obtalned.
Analysls: 16.0~ P; OH ~77 The phosphate esters of this lnvention are - - .
- . ~ . . . . . .

useful as flame retardants for organic polymerc~particular-ly resins, and are ef~ective as reactive flame retardants for polyesters and expecially for rigid polyurethane fOam8.
The OH functionality of these phosphates allows them to be incorporated into the polymer backbone, thu~ providing a permanent flame retardant protection to the polymer. In addition, the preferred compositions, wherein at least Rl and R are ethyl or 2-chloroethyl, are fluid oils at room temperature and are ~oluble ln the polyether polyols normally normally employed in polyurethane production.
This is especially advantageou~ in polyurethane foam manufacture where homogeneity and low viscosity of the components, i.e. polyisocyanates and polyols, are eseential.
When used a~ flame retardants in polymers such as polyesters and polyurethanes, the~e pho6phate ester~
may be incorporated at concentrations of from about 2 to 40 percent, usuAlly from 5 to 15 percent based on the total weight of the polymer.
Example _IV
~ ~ ane Foam ~ his example illustrates the utillty a~ well as the superior efficacy of the compounds of the lnventlon in rigld polyurethane foam The ~oams are prepared using a conventional one shot process employing the recipes li~ted on Table I
(Formulation). For thl~ purpose, all the ingredlents ex-cept the polyl~ocyanate are thoroughly mixed ln a beaker and thereafter the polyisocyanate 1~ added while rapldly agitating the mixture with an air-drl~en ~tirrer. The li~uld contents of the beaker ~re then poured into ~ mold ~'~' ' ' ' .

-16- 10563~3 where within a short period of time a foam develops.
The foam is cured overnight at room temperature, and the flame resistance is determined by the Oxygen Index test (A.S,T.M, D-2863).
Experiment A does not include a flame retardant, and Experiment E contains a well known flame retardant used commercially in rlgid polyurethane ~oams. Experiments A and E are outside the scope of this inventlon.
In Table I the flame resistance data of the ~oams are summarized.
The results lndicate that ln all examples where the compounds of the lnventlon are employed a6 the flame retardant, the oxygen indices achieved are hlgher than those of the blank (A) and of the compari60n experiment (E). The extraordinary and unexpected improvement amounts to over 30% (Expd. C+D) when compared to the prior art compound at substantially the same concentratlon. Even when only one-half of the compound of the inventlon is incorporated in the polyurethane an lmprovement ls achieved (B) over the comparison ~oam (E).

Tabl~ I
Co~porations and Re~ults o~ Ex~
Expêrlment A B ~C D E
Formulation parts by weight Polyol(l) 100 87.6 75 74.2 74.6 Surfactant(2) 2 2 2 2 2 Triethylenedl~nine(3) Dlmethylethanolamlne(3) - 2 2 - 2 Trichlorofluoromethane 30 30 30 45 30 Methylenebl~(phenyl lso-cyanate) (crude)(5) 136 121 127 115 126.5 Phosphate of Example V - 12.4 25 Phosphate o~ Exan~le VII - - - 25.8 Commerclal FIame Retardant(62 - - - 25.4 15 Result~
Ox;rgen Index 20.6 23.6 24.5 24.9 23.5 % Improvement(8) _3.4 34. 48.
Remarks: 1) Propylene oxlde adduct of N-amlnoethylpipe-razlne molecular welght ca. 350, OH ~ ca. 530.
2) Sillcone compound, M-193 of Dow Corning Corp.
3) Catalyst 4) Blowlng Agent 5) Product o~ Rubicon Chemicals, Inc.
6) O-O-dlethyl N,N-ble(Yurdroxyethyl)aminomethyl-phosphonate.
7) ASTM D-2863 8) Calculated accordlng to equatlon % Improvement - ~(OII -OIE)/(oIE-oIo)]x 100 whereln 3o OII = Oxygen index of con~position of invention OIE = " " " Example E (con~arison) OIo - " " " con~positlon wlthout flame retardant (A) - .

-18- 1056393 ::

This example illustrates that the composltlons of this invention provide rlgld urethane foams having excel-lent physical properties. The ~oam ~ormulation iB given in Table II. For compar~son, a widely used reactlve flame retardant (O,O-diethyl N,N-bis(hydroxyethyl)aminomethyl-phosphonate), Experiment C, is also included. The physical properties of the foamæ are summarized in Table II. The test data demonstrate the superior compressive strength of E~periment B of the invention over the polymer without A
flame retardant (A) and the one contalnlng a known flame retardant (C ) .
In addition, friabillty and dimensional stabllity after aging of sample B is superior to that of sample C
which contains the commercial reactive flame retardant.

.. ... . - . . . .. .. . , ........ . ........... ~ .. ... . . ..

: . ~ . : .- . - .

Table II
Results of Exa~le XV
Foam Formulation Components A B C
Polyether polyol(l) 100 100 100 Silicone Surfactant (DC 193 Dow Corning) 1,5 1.5 1.5 Triethylenediamlne 1,0 1,0 1,0 Dibutyltin dilaurante 0,2 0,2 0,2 -Trichlorofluoromethane 40 40 40 Phosphate prepared arcording to Ex~mple V - 20,5~ ) -0,0-Diethyl N,N-bis(hydroxy-ethyl)aminomethylphosphonate - - 25,5(2) 15 Methylenebis(phenylnocyanate (crude) Physical Properties . .
Density, psf 1.96 2,19 2,50 Compressive strength, p8i: .
Parallel to foam rlse34.9 43.9 36,1 Perpendicular to foam rise 19,6 23.7 19,9 Friability, j¢ loss 13,6 17.7 ~ 23.9 % Closed cells 84.5 86.o 84.4 Dimen~lonal Stabllity (1 week), % Vol change 158F, Dry 1,2 0.4 0.5 158F~ 97% RH 4,3 6,o 12,0 25~F, Dry 9,7 13.4 19,4 (1) Propoxylated sorbitol havlng an OH~ of about 550, (2) Foams were formulated to give ~ame phosphorous con-cen+,r~t.ion (ca, 0,9%) for both samples.

-19- ~ :

Claims (23)

What is claimed is:

1. A phosphate ester having the formula RO[(A)m(B)n]H
wherein A has the structural formula and B has the structural formula wherein R,R1 and R2 are the same or different and are linear or branched primary radicals selected from alkyl having 1 to 6 carbon atoms, and haloalkyl and hydroxyalkyl having 2 to 6 carbon atoms; m and n are integers from 0 to about 4 and the sum of m plus n is from 1 to about 4.

2. The phosphate esters of claim 1 wherein R, R1 and R2 are the same.

3. The phosphate esters of claim 1 wherein at least R1 and R2 are substituted with at least one halogen atom.

4. The phosphate esters of claim 1 wherein at least R1 and R2 are substituted with at least one hydroxyl group.

5. The phosphate esters of claim 1 wherein R, R1 and R2 are each selected from the group consisting of methyl, ethyl, propyl, n-butyl, 2-chloroethyl, hydroxyethyl, hydroxy-propyl and 2,3-dibromopropyl.

6. A method for preparing the phosphate ester of claim 1 comprising (a) reacting a polycyclic compound (I) having the formula (C5H804P2)XuYv, wherein X is bromine or chlorine, Y is OR3, wherein R3 is an alkyl group having 1 to 6 carbon atoms or an halo-alkyl group having 2 to 6 carbon atoms, u and v are integers with values of 0, 1 or 2, and the sum of u plus v is 2; with (II) a primary alcohol of the formula HOQ, wherein Q has the the meanings of R3 or is a primary hydroxy-alkyl group having 2 to 6 carbon atoms, in the presence of (III) C12;
(b) the molar ratio of II to I being equal to from about (2u + v):l to 10(2u + v):1, said ratio not exceeding a value of 20, and (c) the molar ratio of III to I being from 2 to 2.2.

7. The method of claim 6, wherein X is bromine or chlorine, u 18 2 and v is O and said ratio of II to I equals 4 to 20.

8. The method of claim 7, wherein said ratio of II to I equals 5 to 12.

9. The method of claim 6, where Y is OR3, u is O and v is 2, said ratio of II to I being 2 to 20.

10. The method of claim 9, wherein said ratio of II
to I is equal to 2 to 7.

11. The method of claim 6, wherein said alcohol (II) is selected from the group consisting of methanol, ethanol, n-butanol, 2-chloroethanol, 2,3-dibromopropanol, 2-hydroxy-ethanol, and 3-hydroxypropanol.

12. The method of claim 7, wherein X is chlorine.

13. The method of claim 6, wherein said compound (I) has a polycyclic structure selected from the group consist-ing of and wherein the Z's may be the same or different and are select-ed from the same groups as X and Y.

14. A flame retardant composition comprising an organic polymer and a flame retarding effective amount of a phosphate ester of the formula RO[(A)m(B)n]H wherein A
has the structure and B has the structure wherein R, R1 and R are the same or different and are linear or branched primary radicals selected from alkyl having 1 to 6 carbon atoms, and haloalkyl and hydrox-alkyl having 2 to 6 carbon atoms; m and n are integers from 0 to about 4 and the sum of m plus n is from 1 to about 4.

15. The flame retardant composition or claim 14 wherein the organic polymer 18 selected from the group consisting of polyester and polyurethane polymers.

16. The flame retardant composition of claim 14 wherein R1 and R2 are the same.

17. The flame retardant composition of claim 14 wherein R and R are each selected from the group consisting of methyl, ethyl, propyl, n-butyl, 2-chloroethyl, 2,3-dibromo-propyl, 2-hydroxyethyl and 3-hydroxypropyl.

18. The flame retardant composition of claim 15 wherein said polymer is a polyurethane polymer.

19. The flame retardant composition of claim 18 where-in said polyurethane polymer is a rigid polyurethane foam and said phosphate ester is chemically bound to and an integral part of the polymer structure.

20. The flame retardant composition of claim 19, where-in R1 and R2 are the same.

21. The flame retardant composition of claim 19, where-in at least one of R1 and R2 is substituted with at least one halogen atom.

22. The flame retardant composition or claim 14, where-in said phosphate ester 18 present at a concentration of from 2 to 40 percent by weight based on the total weight of the polymer.

23. The flame retardant composition Or claim 22 where-in said concentration is from 5 to 15 percent by weight.