US8940907B2 - Synthesis of phosphoric esters - Google …

To isolate the phosphoric acid propargyl esters, which in some cases are heat-labile, it is thus only necessary to wash theorganic phase of the reaction mixture adequately, and to subject it to incipient distillation or a stripping operation to remove low-boiling constituents and, if appropriate, solvents.

Alkyl Esters of Phosphoric Acid - Industrial & …

Synthesis of bis(glycoaldehyde) phosphodiester and mixed glycoaldehyde-triose phosphodiesters.

Alkyl Esters of Phosphoric Acid

Table 4 summarizes some of the phosphorous acid-related compounds and research on their efficacy against potato late blight. In most cases, phosphorous acid is applied to the foliage. The compound is translocated from the shoots to the roots and can, therefore, also control oomycetes that affect roots. Phosphorous acid was shown to be effective when applied as a root drench against P. cinnamomi, P. nicotianae, and P. palmivora in lupin, tobacco, and papaya, respectively (Smillie, Grant, and Guest 1989). The efficacy of different phosphonate compounds against nine Phytophthora spp. that cause stem rot of Persea indica L. and pepper was tested both as a curative and preventive method of control by Ouimette and Coffey (1989a). Although there were notable differences in the sensitivity of the Phytophthora spp. in their experiments (Table 4), there was little variation in the ability of phosphonates to control stem rot of pepper, regardless of its use as a curative or a preventive agent in pots. A greater level of control was obtained for Persea indica L. than for pepper (Ouimette and Coffey 1989a).

Esters of Phosphoric Acid - 2012 Book Archive

A major factor in the ability of phosphorous acid to control oomycetes appears to be its chemical stability in the plant (Smillie, Grant, and Guest 1989). Phosphorous acid does not convert into phosphate and is not easily metabolized (Ouimette and Coffey 1989b). The stability of different phosphonate-related compounds may depend on environmental factors, such as climate or crop type. Because phosphonate is systemic and stable in plants, it should be applied infrequently in order to avoid accumulation problems. Plant species may differ in phosphonate uptake and translocation (Cooke and Little 2001), and individual P. infestans isolates show great variation in sensitivity (Bashan, Levy, and Cohen 1990; Coffey and Bower 1984) to phosphonate compounds, which may impact the effectiveness of phosphonate.

Yield: 45% of phosphoric acid propargyl ester dichloride, undistilled.

Synthesis of the Phosphoric Esters: ..



It has now been found that the yield and purity in the preparation of phosphoric acid alkyl propargyl esters and phosphoric acid aryl propargyl esters can be further increased if the synthesis is carried out as a two-phase reaction in thepresence of catalytic amounts of tertiary amines or quaternary ammonium or phosphonium salts with at least 9 C atoms, and an inorganic base in at least equimolar quantity is used as an acid-trapping agent.

Phosphoric acids and phosphates - Wikipedia



If a tertiary amine is used as the catalyst, this is preferably added to the batch to the extent of about 1 to 10 mol %, and about 0.01 to 1 mol % of quaternary ammonium or phosphonium salt suffices; the mol % in each case is relative tophosphoric acid ester chloride.

The yield of phosphoric acid diethyl propargyl ester over the two stages was thus 25.2%.

Chemical synthesis of several phosphoric esters of ..



In similar, but uncatalyzed, reactions, the aliphatic alcohol is usually employed in a large excess in order to keep the hydrolysis, which proceeds as a side reaction, of the phosphoric acid ester chloride and of the phosphoric acid triesterformed as low as possible.

SYNTHESIS OF PHOSPHORIC ACID ESTERS OF α …

However, it is sufficient and thus preferable to limit the excess of propargyl alcohol to 0 to about 10 mol %, relative to phosphoric acid ester chloride.

Synthesis and Testing of Phosphoric Acid Esters …

Against this background, it was not to be expected that phosphoric acid esters can be prepared ingood purity and in yields of up to 96% by the reaction of phosphoric acid ester halides with propargyl alcohol, which is not very reactive, by the process according to the invention, even if the propargyl alcohol is employed in only a slight excess of 0to 10 mol %.