The invention relates to the process for preparing ethylenedialkylphosphinic acids, esters and salts, wherein a) a phosphonic acid source (I) is reacted with olefins (IV) in the presence of a catalyst A to give an alkylphosphonous acid (II), or salt or ester thereof, b) the alkylphosphonous acid (II), or the salt or ester thereof, is reacted with an acetylenic compound (V) in the presence of a catalyst B to give the ethylenedialkylphosphinic acid derivative (III) where R1, R2, R3, R4, R5, R6, FR11, R12, R13, R14 are the same or different and are each independently H, C1-C18-alkyl, C6-C18-aryl, C6-C18-aralkyl, C6-C18-alkylaryl, where the C6-C18-aryl, C6-C18-aralkyl, C6-C18-alkylaryl groups may be substituted by -C(O)CH3, OH, CH2OH, NH2, NO2, OCH3, SH and/or OC(O)CH3, and X is Mg, Ca, Al, Sb, Sn, Ge, Ti, Fe, Zr, Zn, Ce, Bi, Sr, Mn, Cu, Ni, Li, Na, K, H and/or a protonated nitrogen base, and/or is H, C1-C18-alkyl, C6-C18-aryl, C6-C18-aralkyl, C6-C18-alkylaryl, (CH2)kOH, CH2-CHOH-CH2OH, (CH2)kO(CH2)lH, (CH2)k-CH(OH)-(CH2)lH, (CH2-CH2O)kH, (CH2-C[CH2]HO)kH, (CH2-C[CH3]HO)k(CH2-CH2O)lH, (CH2-CH2O)k(CH2-C[CH3]HO)H, (CH2-CH2O)k-alkyl, (CH2-C[CH3]HO)k-alkyl, (CH2-C[CH3]HO)k(CH2-CH2O)l-alkyl, (CH2-CH2O)k(CH2-C[CH3]HO)O-alkyl, (CH2)kNH2, (CH2)kN[(CH2)lH]2, where k and I are the same or different and are each independently an integer from 0 to 20, and m is 1 to 4, and the catalyst A comprises transition metals and/or transition metal compounds and/or catalyst systems composed of a transition metal and/or a transition metal compound and at least one ligand, and the catalyst B comprises electromagnetic radiation.本發明關於製備伸乙二烷基亞膦酸、酯和鹽之方法，其中a)亞膦酸來源(I)與烯烴(IV)在觸媒A之存在下反應以產生烷基亞膦酸(II)、或其鹽或酯，b)該烷基亞膦酸(II)、或其鹽或酯與炔化合物(V)在觸媒B之存在下反應以產生伸乙二烷基亞膦酸衍生物(III)其中R1、R2、R3、R4、R5、R6、R11、R12、R13、R14 為相同或不同且各自獨立地為H、C1-C18-烷基、C6-C18-芳基、C6-C18-芳烷基、C6-C18-烷芳基，其中該C6-C18-芳基、C6-C18-芳烷基、C6-C18-烷芳基可經-C(O)CH3、OH、CH2OH、NH2、NO2、OCH3、SH及/或OC(O)CH3取代，及X 為Mg、Ca、Al、Sb、Sn、Ge、Ti、Fe、Zr、Zn、Ce、Bi、Sr、Mn、Cu、Ni、Li、Na、
