III IIII US005536880A United States Patent (19) 11 Patent Number: 5,536,880 Sugiya et al. 45) Date of Patent: Jul. 16, 1996 (54) MONOALKYLPHOSPHINE AND METHOD Primary Examiner-Paul J. Killos OF PRODUCING THE SAME Attorney, Agent, or Firm–Oblon, Spivak, McClelland, 75) Inventors: Masashi Sugiya; Seiji Shimura, both Maier & Neustadt of Tokyo, Japan 73) Assignee: Nippon Chemical Industrial Co., Ltd., (57) ABSTRACT Tokyo, Japan A monoalkylphosphine represented by the following for mula (1): (21) Appl. No.: 359,821 22 Filed: Dec. 20, 1994 (H, CH, gh (1) 30 Foreign Application Priority Data H CH,- CH-i-CH, (-CH H CH3 PH2 CH3 Dec. 24, 1993 (JP) Japan .................................... 5-329005 Dec. 24, 1993 (JP Japan .................................... 5-329006 wherein m indicates 1 or 2, and n indicates an integer of 0 (51) Int. Cl. ............................................. C07F 9/50 to 2. The monoalkylphosphine can effectively be obtained by reaction between phosphine and an alkene in the presence (52) U.S. Cl. ................................................................... 568/8 of an organic solvent and an anhydrous alkanesulfonic acid (58) Field of Search .................................................... 568/8 catalyst. 56) References Cited U.S. PATENT DOCUMENTS 5,354,918 10/1994 Ohsaki et al. .............................. 568/8 8 Claims, No Drawings 5,536,880 1. 2 MONOALKYLPHOSPHINE AND METHOD an intermediate of functional organic phosphorus com OF PRODUCING THE SAME pounds in consideration of the above-described facts, the inventors found a novel monoalkylphosphine compound. The inventors also found that a high yield of high-purity BACKGROUND OF THE INVENTION monoalkylphosphine can be obtained without dialkylphos 1. Field of the Invention phine and trialkylphosphine by reaction of phosphine and an The present invention relates to a novel monoalkylphos alkene in the presence of an organic solvent and anhydrous phine, and particularly, to a novel monoalkylphosphine alkanesulfonic acid as a catalyst. The present invention has been achieved on the basis of that finding. useful for imparting flame retardancy, antistatic properties, O etc. to fibers and plastics. SUMMARY OF THE INVENTION The present invention further relates to a method of producing monoalkylphosphine useful for imparting flame In accordance with one aspect of the present invention, retardancy, antistatic properties, etc. to fibers and plastics, there is provided a monoalkylphosphine represented by the with good selectivity and yield. 5 following general formula (1): 2. Discussion of the Prior Art Recentry there have been demands for highly-functional (H, ch (H, m (1) fibers and plastics having flame retardancy, the ability to modify resins, antistatic properties, etc. Organic phosphorus H CH,- CH-C-CH, (-CH, H compounds, e.g., monoalkylphosphines such as methylphos 20 CH PH CH3 phine, are used for these purposes. Methylphosphine is wherein m indicates 1 or 2, and n indicates an integer of 0 gaseous at room temperature under atmospheric pressure, to 2. and it will easily ignite and explode on contact with air. In accordance with another aspect of the present inven Methylphosphine is thus very dangerous and difficult to tion, there is provided 2-phosphino-2,4,4-trimethylpentane handle, and furthermore has high toxicity. Therefore, a 25 as a monoalkylphosphine represented by the above formula monoalkylphosphine which is easy to handle and having low (1). toxicity is desired. In accordance with a further aspect of the present inven It is disclosed that a polyester copolymerized with bis(2- tion, there is provided a method of producing monoalky carboxyethyl) methylphosphine oxide derived from meth lphosphine comprising reacting phosphine and an alkene in ylphosphine exhibits good flame retardancy (U.S. Pat. No. 30 the presence of an organic solvent and a catalyst consisting 4,127,566). However, the copolymer thus produced has the of at least one anhydrous alkanesulfonic acid of the follow faults that the melting point is significantly decreased, and ing general formula (2): that heat resistance is a little low. The monoalkylphosphine of the present invention is a novel compound which improves on the above points, has 35 R-SOH (2) excellent performance as a modifier for fibers and plastics, wherein Rindicates an alkyl group having a carbon number and can be easily produced with high purity. of 1-4. A conventional method of producing monoalkylphos phine is through synthesis using a radical polymerization 40 DETALED EXPLANATION OF THE catalyst. However, this method produces a mixture of INVENTION mono-, di- and trialkylphosphine due to reaction by a radical catalyst which has no selectivity, and thus high-purity The present invention will be explained in detail below. monoalkylphosphine cannot be obtained even by purifica The monoalkylphosphine of the present invention is a tion distillation of the mixture. The method also has the 45 novel compound having such physical properties that it is disadvantage of low yield J. Org. Chem., 26, 5138-5145 gaseous at room temperature under atmospheric pressure, (1961). Unlike the present invention, the method produces and that since the boiling point of, for example, 2-phos a mixture of mono-, di- and trialkylphosphines having alkyl phino-2,4,4-tributylpentane, is 79° to 80° C. (62 mmHg), it group substituent in the form represented by the following has low vapor pressure and is thus very easy to handle. The formula: 50 compound is also safe because of its low tendency to explosively react with air and ignite, and the toxicity thereof decreases with an increase in the size of the alkyl groups. (H, Further, the compound can be used widely as a flame Hip-CH-CH-CH-i-CH retardant, an antistatic agent, an antibacterial agent, a dye CH CH 55 modifier, a resin modifier, a stain-proofing agent, an anti corrosive agent, etc. in various fields, and is thus a useful Another method by reaction of phosphine and an alkene organic phosphorus compound. in the presence of an acid catalyst is known J. Org. Chem., The production method of the present invention is char 24, 356-359 (1959), U.S. Pat. No. 2,584,112). Since this acterized by a reaction in which when an alkene having a method uses as the acid catalyst an aqueous solution of 60 large carbon number is reacted, the reaction proceeds alkanesulfonic acid, dialkylphosphine and trialkylphosphine smoothly, and, unlike a reaction with an alkene having a are easily produced as by-products, and these by-products small carbon number, the organic solvent contains only the cannot be easily removed. Also yield is inevitably decreased intended monoalkylphosphine after the reaction is com due to side reactions. pleted, thereby eliminating the need for purification. Also, As a result of extensive research on monoalkylphosphine 65 the alkylphosphine produced as a by-product of the reaction as a flame retardant for polyester (U.S. Pat. No. 4,127,566, does not contain trialkylphosphine, and the dialkylphos and Japanese Patent Laid-OpenNo. 52-33628) and useful as phine produced as a by-product is caught by the alkane 5,536,880 3 sulfonic acid layer of the catalyst. That is, high-purity monoalkylphosphine can be obtained by separation after the completion of reaction. R-SOH (2) The production method of the present invention is also characterized in that the reaction is effected in an anhydrous 5 wherein Rindicates an alkyl group having a carbon number system. Reaction in an anhydrous system can inhibit the of 1 to 4. Examples of such catalysts include methane production of dialkylphosphine or trialkylphosphine com sulfonic acid, ethanesulfonic acid, propanesulfonic acid, pounds which are inevitably produced as by-products of butanesulfonic acid and the like. These catalyst may be used reaction in an aqueous system. Since the anhydrous alkane alone or in mixture of two or more compounds. Although the sulfonic acid catalyst can trap even trace amounts of water catalyst must be anhydrous, any anhydrous catalyst which is in the apparatus by its inherent dehydrating ability of the 10 industrially available may be used, and their water content catalyst itself, the reaction in the anhydrous system can be is generally 0.1% or less, preferably 500 ppm or less. Since completed while preventing completely any mixing with these nonoxidizing, strong, lower-alkanesulfonic acids hav water, thereby obtaining high-purity monoalkylphosphine. ing a carbon number of 1 to 4 are frequently unstable, they Although the reaction is preferably effected in an anhydrous are preferably purified by distillation before use. system, any catalyst and solvent which is industrially avail 15 The ratio of the amount of catalyst used to the alkene raw able may be used without any real need for purification. material, the alkene raw material being 1 mol, should be (Compound of the Invention) about 0.1 to 2.0 mols, preferably 0.8 to 1.0 mol. The monoalkylphosphine compound of the present inven (Solvent) tion is a novel compound represented by the above formula Saturated hydrocarbons having a carbon number of 1 to 8, (1), wherein m is 1 or 2, and n is an integer of 0 to 2. 20 which are easily commercially available are suitable as the Examples of such compounds of the present invention reaction solvent in the present invention, except organic include 2-phosphino-2,4,4-trimethylpentane, 4-phosphino solvents having boiling points higher than the boiling point 2,2,4,6,6-pentamethylheptane, 4-phosphino-2,2,4,6,6,8,8- of the produced monoalkylphosphine. heptamethylnonane, 2-phosphino-2,4,4,6,6-pentamethyl Examples of such solvents include n-pentane, n-hexane, heptane, 6-phosphino-2,2,4,4,6,8,8,10,10-nonamethylunde 25 isohexane, n-octane, n-isooctane, n-decane, petroleum ether, cane and the like. petroleum benzine, ligroin, petroleum spirit, petroleum (Method of Producing Compound of the Invention) naphtha, cyclohexane, methylcyclohexane, benzene, tolu The monoalkylphosphine of the present invention can be ene, xylene, ethylbenzene and the like.