View of SYNTHESIS AND HYDROLYTIC REACTIVITY OF TRI-SUBSTITUTED ARYLPHOSPHORIC TRIAMIDE

(1)

ACCENT JOURNAL OF ECONOMICS ECOLOGY & ENGINEERING Available Online: http://ajeee.co.in/index.php/AJEEE

Vol.02, Issue 01, January 2017, ISSN -2456-1037

1

SYNTHESIS AND HYDROLYTIC REACTIVITY OF TRI-SUBSTITUTED ARYL- PHOSPHORIC TRIAMIDE

DR. AMITA SAXENA

Assistant Professor, Biotechnology Department, Amity University, Gwalior

Abstract:-Trioxide Phosphoramidate hydrolysis via Neutral and the conjugate acid species with a rate maximum at 4.0m Hcl at 90 (+0.5)oC in 20% DmSO-H2O mixture . The special feature of the study is that the hydrolysis proceeds via the corresponding diamide as well as the phosphoric monoamine.

Keywords:-Phosphoric triamide, Allen’s method, Dipolar Aprotic medium, P-N bond fission.

INTRODUCTION

Organic Phosphates are known as flame proofing agents¹, Petroleum additives², Synthetic reagents³, rust preventives and insecticides⁴ etc. They also shows both⁵nucleophile and electrophonic catalysis.

EXPERIMENTAL DETAILS

o-NO2, p-cl- Aniline with phosphorus oxychloride⁶ (4:1) in the presence of catalytic amount of morphine in benzene (day) on refluxing for nearly 10 hrs gave a yellow brown mass (on cooling) It was quantitatively tested by Allen's modified mthod⁷ for phosphorous. The results are as :

1. M.P.(Observed ) of the triamichate = 186°CPercentage of phosphorous

=5.52(both theo.& Obsd.)

2. The synthesized phosphorotriamidate has been examined for its characteristics structural features by I.R. spectros copy followed by N.M.R.spectral⁸ measurements.

RESULTS AND DISCUSSIONS

The kinetic study during hydrolytic degradation has been performed, between the acid range 0.01 - 7.0 M HCl medium.

The quantitative estimation of the end product, H3PO4was done by Allens modified method⁷ observed rate coefficients are of the 1^storder type, but due to excess of the medium, the overall order is of pseudo-first order type with the rise in acid, molarity, rate maximum had been observed at 4.0 M-HCl (Table 1) suggesting a moderate basic character of the di-substituted Phenyl phosphorictriamide. Ionic strength studies⁹ (Fig.1) shows presence and contribution of the two major reactive species, neutral and the conjugate acid species mainly. The former has a fixed value (Kn=1.05 x 10^-2 min^-1) on the basis of variations due to ionic strengths changes on the neutral rates in the medium 20% DMSO-H2O. Neutral species operates between 0.01m HCl to 1.0 m HCl only. The

(2)

2 conjugate acid species participate in the entire acid range examined for determining the calculated rates via the reactive forms the second empirical term of Debye Hiickel equation⁹ (iv) has been used as described below.

Ke = KH+. CH+ + KN ...(i) Here KN=1.0 x 10^-2 min^-1...(ii) KH+. CH+= KH0+ .ebH+μ ...(iii) where, KH+= Acid catalyzed rate

KH0+= Acid catalyzed rate at zero ionic strength

bH+= slope

KN = Rate via the Neutral species from equation (iii) the calculated rates on the basis of negative strength effect on the acid catalyzed rates are derived after solving it logarithmically

log KH+. CH+ = log KH0+ log CH+ -

bH+μ………..(iv)

The specific acid catalysis operates in the higher acid (.1.0M-Hcl) media.Neutral species operates in the low acid range (Table 1) varyingbetween 0.01 M to 1.0 MHCl. Conjugate acid species however contributes in the entire acid range 0.01- 7.0 MHCl in 20% DMSO-H2Omixture.

Table I:Observed Acid-Rate and Log Acid-Log Rate Data for the Hydrolysis of o-NO2, p- Cl-phenyl phosphoric trioxide (20% DMSO v/v) at 90 (±0.5)⁰C.

S.No Acid

(M) 10²ke.obsd.

min^-1 2+logCH+ 3+logkeobsd.

min^-1

1 0.01 4.08 0.00 1.61

2 0.1 3.76 1.00 1.57

3 0.5 3.55 1.70 1.55

4 1.0 3.99 2.00 1.60

5 2.0 4.51 2.30 1.65

6 3.0 4.41 2.48 1.64

7 4.0 17.91 2.60 2.25

8 5.0 14.28 2.70 2.15

9 6.0 16.60 2.78 2.22

10 7.0 16.69 2.84 2.22

Note:-keobsd. = 0.60 X 10^-2 min^-1 in 20% DMSO-H2O mixture only.

TEMPERATURE EFFECT¹⁰ STUDY During the kinetic study it was observed that the phosphoric triamiche at 90 (±0.5)°C in 20% . DMSO¹¹ – H2O (V/V) dissociates into the corresponding diamide [40 (±0.5)°C in 18% . DMSO – H2O (V/V] and thus Arrhenius Parameter data given below for the diamide (1.0

MHCl) forms the basis of the study of the trioxide as well.

Energy of

activation Frequency

factor Entropy of

activation Enthalpy of activation

Free energy

ΔEKJmol^-1 Asec^-1 ΔS≠e.u. ΔH≠

KJmol^-1 ΔG≠KJ.mol^-1

68.59 9.45x10⁷ -0.052 66.00 65.91

CONCENTRATION EFFECT STUDY This concentration effect¹⁰ study had been conducted at 1.0M-HCl at 90 (±0.5)°C in 32% DMSO-H2O mixture thus leads to

first order rates in favor of the phosphoric trioxide as the substrate. However pseudo 1^storder is the overall order due to the medium (32% DMSO H2O) being in much

(3)

3 excess. It also shows that the order is not much different from molecularity. The following data shows that the rates remain constant irrespective of the fact that the concentration is remain doubled each time.

Concentration 5.0 x10^-4 M

10.0 x

10^-4M 20.0 x

10^-4 M 10²Ke min^-1 8.35 7.85 7.66

CONCEPTS12 IN HIGHER ACID MEDIA In order to determine the effect of higher acid media related to molecularity concepts in higher acid media were applied during the study. Hammett - plot (slope = 0.25, ˂1.0) and Ziicker - Hammett plot (0.76) both favor bimolecularity of the hydrolysis reaction Bannett plot12(w=5.58 and W* = 1.33) (~1.0) along with Bunnetolsen plot14 (Φ=1.07) all favour13 bimolecularity. The value of Φ suggests protonation14 via the formation and attack of an polonium ion H3O+ on the C-N-P nitrogen of the compound under observation. It also concludes that water actually participates during hydrolysis . Yates and Mccleland15 plot (γ=2.35) shows that only two water molecules are actually involved during hydrolysis. The formation of the corresponding aryl amine was checked qualitatively by an azo dye test16 resulted P-N bond fission.

CONCLUSION

Phosphotriamidates may or may not hydrolysis via the correspondingo-NO2, p- Cl Phenyl Phosphoric diamide. The bulkiest Phosphoric Trioxide is the most stable member. Mechanistic routes have been decided based on the two reactive forms Neutral and conjugate acid species.

REFERENCES

1. Murch, Robert M.,U.S.,3,992, 352, 16th Nov. 1976, C.A., Vol 86, No.6 1977, 3058p.

2. A Streitwieser, and C.H.Heathcock,'Intro. to organic chemistry, Collier MacMillan Inter Eds (1976), pp.1036 .

3. HelgeKlare , J. Org, M.Neudrofl and Beilstein, Bernd Goldguss J.Org. Chem. 2014 10, 224-236.

4. Protopova, G.V.Pavlenko, A.F.Reidalova, L.I.Fiziol.

Akt/ Veshest-va, 1976,8,19-20 (Russ).

5. W.P.Jencks, Catalysis in Chemistry and Enzymology, McGraw-Hill Book Co.Newyork, pp 76- 77, 148 (1969).

6. Allens ,R.J.L.Biochem. J.34 858 (1940).

7. Benkovic, stephen J. and Benkovic, Patricia A.J. Am Chem Doc. 89 4714 (1967).

8. R.M.Silverstein and Francis X.Webster,

"Spectrometric Identification of Organic Compounds

", Sixth ed. John Wiley & Sons New York (2002), pp.

142, 291-293.

9. R.A.Robinson, R.H.Stokes, “Electrolyte solutions", Butters worth Scientific Publications London (1959) pp 559.

10. E.S.Swinbourne "Studies in Org chem.” Analysis of Kinetic Data Nelson (1971) pp 47, 53-55.

11. D.Martin and H.G. Hauthal "Dimethyl Sulphoxide", Van No strand Reinhold Co. Ltd, England (1975) pp.

271.

12. Bunnett. J.F., J. Am.ChemSoc, 1961 83 4956.

13. J.F.Bunnett and F.P.Olsen, Can J.Chem., 44 1899, 1917 (1966).

14. Jiang J.C. Wang, Y.S. Chang, H.C., Lin S.H.., Lee, Y.T.Niendner

15. Schatterburg, G.J. Am. Chem. Soc, 2000, 122, 1398-1410.

16. Yates K. and McClelland, R.A.J.Am. Chem. Soc.

1967 89 2686.

17. Jerry March, 'Advanced Organic chemistry," 4^thed.

John Wiley & Sons, Newyork (2000) pp. 659.