CH548420A - Phosphonitrile esters, flameproofing agents - Google Patents

Abstract

Flame retardant additives for textiles and synthetic fibres comprise phosphontrile esters of formula: (where n = 1-10, Y = a halogen atom or a radical of formula (a) or (b) or the two free valencies are fixed on the same P atom forming a ring with it, or are bonded to two different P atoms; At least one Y is in formula (I) = (a) or (b) where = 0 or 1 and r1R2 and R3 = same or diff lower halo alkyl).

Description

  

  
 



   The present invention relates to a process for the preparation of phosphonitrile esters, which is characterized in that 1 molar equivalent of a phosphonitrile halide of the formula PnNnHal2n, (I) where n is a number from 3 to 12 and Hal is chlorine, bromine or fluorine, with n- 1 to n molar equivalents of a propane-1,3-diol of the formula
EMI1.1
 where R1 and R2, independently of one another, each represent a low molecular weight, halogenated alkyl radical.



   As phosphonitrile halides, for. B. reaction products of ammonium halides and phosphorus pentahalides, preferably of NH4Cl and PCl5, are in question. In general, you can directly the resulting mixtures or the fractions isolated therefrom, for. B.



     Use PsN3Clr, P4N4Cls or PXNxCl2x, where x is greater than 4.



   The reaction can be carried out in an organic solvent such as. B. ethers, such as dioxane, 1,2-dimethoxy or diethoxyethane, 1-ethoxy-2 - [(2'-ethoxy) ethoxy] ethane, tetrahydrofuran, aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, halogenated aliphatic or aromatic hydrocarbons such as chloroform, trichlorethylene, chlorobenzene, ortho-dichlorobenzene, bromobenzene, ketones such as propanone-2-propanone, butanone-2, 4-methylpentanone-2, 2,6-dimethyl-heptanone-4, also acetonitrile, dimethylformamide and acetamide, dimethyl sulfoxide, tetramethylene sulfone, phosphoric acid tris (dimethylamide), etc.



   The reaction is advantageously carried out in the presence of an acid-binding agent.



   As such comes z. B. Consider:
Alkali metal hydroxides and carbonates such as potassium, sodium or lithium hydroxide or carbonate, alkaline earth metal hydroxides and carbonates such as calcium, magnesium or barium hydroxide or carbonate. Tri- (lower alkyl) amines such as triethylamine, tributylamine or trimethylamine, pyridine, picolines, quinoline, etc.



   If tertiary amines are used as acid-binding agents, these can also serve as solvents. After the reaction has ended, the reaction product, for. B. precipitate by diluting with a suitable agent, preferably with water, optionally with the addition of an acid, or with an alcohol such as methanol, ethanol or isopropanol, suction and dry. The solvent can also be removed by distillation, preferably under reduced pressure, and the residue with a suitable agent, e.g. B. methylene chloride or chloroform, extract.



   The halogenated phosphomitrile esters obtained are colorless, crystalline solids which are readily soluble in many organic solvents. The esters prepared according to the invention have a high thermal stability and are suitable, for. B. as a flame retardant for plastics and resins.



   Preference is given to the compounds of the formula (II) in which R1 and / or R2 are —CH2Hal, where Hal is bromine or chlorine.



   In the following examples, which illustrate but do not limit the invention, the parts are parts by weight and the percentages are percentages by weight. The temperatures are given in degrees Celsius.



   example 1
A solution of 49 parts of P3N3Cl6 in 220 parts of tetrahydrofuran is added successively at 20 with 73.5 parts of 2,2-bis- (chloromethyl) -propane-1,3-diol and 74 parts of pyridine. The reaction mixture is then stirred for 22 hours at room temperature and then for 12 hours under reflux, where pyridine hydrochloride is formed as a precipitate. The reaction mixture is cooled, the salt is filtered off and the filtrate is poured into 1000 parts of water, the reaction product precipitating out as a white precipitate.



  After drying, the product shows a melting range of 116-1200. It is readily soluble in many organic solvents, such as B. in aromatic or chlorinated hydrocarbons, acetone, ethyl acetate, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethylsulfoxis or phosphoric acid tris (dimethylamide).



   Example 2
A solution of 66 parts of P3NsClo in 300 parts of tetrahydrofuran is added successively at 200 parts with 150 parts of 2,2 bis (bromomethyl) propane-1,3-diol and 110 parts of pyridine. The reaction mixture is then stirred for 2 days at room temperature and then for 8 hours at 750, with pyridine hydrochloride separating out as a precipitate.



  The reaction mixture is cooled, the salt is filtered off and the filtrate is concentrated, and 1000 parts of water are added to the above residue, the reaction product separating out as a yellowish precipitate. The product can be purified by reprecipitation with acetone / water and obtained almost colorless. The product has a melting range of about 2000 to 2200 C. It is soluble in the solvents specified in Example 1.



   Example 3
A solution of 116 parts of a mixture of oligomeric phosphonitrile chlorides of the approximate composition 60 to 70/0 P3N3Cl6, 10-15 0 / o P4N4Cls and 30-15 O / o PXNxClSx, where x> 4 and 325 parts 3-bromo-2.2 -bis (bromomethyl) -1-propanol in 890 parts of tetrahydrofuran is mixed with 100 parts of pyridine and reacted and worked up in the manner indicated in Example 2.

 

  The reaction product softens at 900 and is similar in its solubility properties to the products described in Examples 1 and 2.



   Example 4
To 90 parts of an unsaturated polyester based on a precondensate of maleic acid glycol and styrene (Polylite 8170 from Reichhold) were added 10 parts of a compound prepared according to Example 3 and, as catalysts, 1 part of methyl ethyl ketone peroxide and 0.1 part of cobalt in a beaker with vigorous stirring -naphthenate added and'well distributed. The mixture was poured between 2 glass plates and heated at 800 for 5 hours in a drying cabinet.



   The polyester resins obtained have an LOI value of 27.7. They are self-extinguishing according to ASTM D-635.



  A corresponding polyester resin without the addition of the flame retardant, on the other hand, has an LOI value of 19.0 and burns completely according to ASTM D-631.

 

Claims (1)

PATENT CLAIMS I. A process for the preparation of phosphonitrile esters, characterized in that 1 molar equivalent of a phosphonitrile halide of the formula PnNnHal2n, (I) where n is a number from 3 to 12 and Hal is chlorine, bromine or fluorine, with n-1 to n molar equivalents of a propane -1,3-diols of the formula EMI2.1 where R1 and R2, independently of one another, each represent a low molecular weight, halogenated alkyl radical. II. The compounds prepared by the process according to claim I. III. Use of the compounds prepared by the process according to patent claim I for making organic compounds flame-resistant outside the textile industry. SUBCLAIMS 1. The method according to claim I, characterized in that 1 mol of trimeric phosphorus nitrile chloride is reacted with 3 mol of 2,2-bis (chloromethyl) propane-1,3-diol. 2. The method according to claim I, characterized in that 1 mol of trimeric phosphorus nitrile chloride is reacted with 3 mol of 2,2-bis- (bromomethyl) -propane-1,3-diol.