The present subject matter provides a safe alternative for producing an important intermediate useful for preparing the herbicide glufosinate, without need for chlorine components in the manufacturing process. In particular, a process for preparing alkyl phosphinic aid alkyl ester is provided, including the step of alkylating alkyl phosphinic acid ester in a non-polar solvent in the same apparatus as used to first produce the alkyl phosphinic acid ester, and without isolating the alkyl phosphinic acid ester before the alkylation step is conducted. More specifically, a process is presented for preparing methyl phosphinic acid butyl ester, by alkylating butyl phosphinic acid ester in a non-polar solvent, in the same apparatus as used previously to first produce the butyl phosphinic acid ester and without isolating the butylphosphinic acid ester before alkylation.

Provided are a method for preparing L-glufosinate and the intermediate compounds of formula (V) and formula (III).

The present disclosure relates to a novel crystalline form of L-glufosinate ammonium salt and a process for preparation thereof. The present disclosure also provides compositions comprising said form and a method for the control of undesired plant growth using said compositions.

A preparation method for glufosinate or a salt thereof, an enantiomer thereof, or mixtures of the enantiomer thereof in all ratios, comprising reacting a compound of formula (II) or a salt, an enantiomer, or mixtures of the enantiomer in all ratios with one or more compounds of formula (III) or mixtures thereof. ##STR00001##

The invention relates to mixtures of at least one diphosphinic acid of the formula (I)

##STR00001## in which R.sup.1, R.sup.2 are the same or different and are each independently H, C.sub.1-C.sub.18-alkyl, C.sub.2-C.sub.18-alkenyl, C.sub.6-C.sub.18-aryl, C.sub.7-C.sub.18-alkylaryl, R.sup.5 is C.sub.1-C.sub.18-alkylene, C.sub.2-C.sub.18-alkenylene, C.sub.6-C.sub.18-arylene, C.sub.7-C.sub.18-alkylarylene with at least one dialkylphosphinic acid of the formula (II)

##STR00002## in which R.sup.3, R.sup.4 are the same or different and are each independently C.sub.1-C.sub.18-alkyl, C.sub.2-C.sub.18-alkenyl, C.sub.6-C.sub.18-aryl and/or C.sub.7-C.sub.18-alkylaryl.

The invention also relates to a process for preparing these mixtures and to the use thereof.

The present provides a process for preparing dialkyl phosphinate, comprising: (1) firstly adding 0-99% of the total weight of phosphinic acids and/or salts thereof and a solvent into a reaction kettle; (2) in the reaction kettle in the presence of alkene and initiator, continuously adding 1-100% of the total weight of the phosphinic acids and/or salts thereof into the reaction system, during the addition process, when the mole contents of monoalkyl phosphinic acids and/or salts thereof account for 10% or less of the total molar contents of phosphorus in the reaction system, stopping adding the phosphinic acids and/or salts thereof. Also providing a dialkyl phosphinate flame retardant prepared by above preparation process.

Provided is a method for preparing L-glufosinate from an L-homoserine derivative compound, the method including a step (step a) of preparing a compound of Chemical Formula 2 from a compound of Chemical Formula 1, and a step (step b) of preparing a compound of Chemical Formula 3 from the compound of Chemical Formula 2.

Methods for preparing crystalline L-glufosinate ammonium monohydrate are disclosed. The methods include forming a mixture comprising water, a water-miscible organic solvent, ammonium hydroxide, and a glufosinate starting material containing L-glufosinate ammonium and D-glufosinate ammonium. L-Glufosinate ammonium monohydrate is crystallized and separated from the mixture, providing L-glufosinate ammonium monohydrate Form B. Compositions and methods employing the crystalline L-glufosinate ammonium monohydrate are also described.

The present disclosure relates to a novel crystalline form of L-glufosinate ammonium salt and a process for preparation thereof. The present disclosure also provides compositions comprising said form and a method for the control of undesired plant growth using said compositions.

A preparation method for glufosinate ammonium or a salt thereof, an enantiomer thereof, or mixtures of the enantiomer thereof in all ratios, comprising reacting a compound of formula (II) or a salt, an enantiomer, or mixtures of the enantiomer in all ratios with one or more compounds of formula (III) or mixtures thereof.

##STR00001##