Solvolysis Reactions Research Articles

Onset of Hydrogen Bonded Collective Network of Water in 1,4-Dioxane

We have studied the evolution of water hydrogen bonded collective network dynamics in mixtures of 1,4-dioxane (Dx) as the mole fraction of water (X(w)) increases from 0.005 to 0.54. The inter- and intramolecular vibrations of water have been observed using terahertz time domain spectroscopy (THz-TDS) in the frequency range 0.4-1.4 THz (13-47 cm(-1)) and Fourier transform infrared (FTIR) spectroscopy in the far-infrared (30-650 cm(-1)) and mid-infrared (3000-3700 cm(-1)) regions. These results have been correlated with the reactivity of water in these mixtures as determined by kinetic studies of the solvolysis reaction of benzoyl chloride (BzCl). Our studies show an onset of intermolecular hydrogen bonded water network dynamics beyond X(w) ≥ 0.1. At the same concentration, we observe a rapid increase of the rate constant of solvolysis of BzCl in water-Dx mixtures. Our results establish a correlation between the onset of collective hydrogen bonded network with the solvation dynamics and the activity of clustered water.

Structural effects responsible for stability and solvolytic reactivity of sulfonium ions

The solvolysis rates of X‐substituted benzhydryltetrahydrothiophenium ions (1) in pure and aqueous alcohols were determined at 25 °C and compared with the rates of the corresponding benzhydryldimethylsulfonium ions (2). The linear free energy relationship equation log k = sf(Ef + Nf) has been used to relate quantitatively the leaving group abilities of tetrahydrothiophene (THT) and dimethyl sulfide (Me2S). It has been demonstrated that although generating a stronger base by heterolysis, substrates 1 solvolyze over lower barriers than 2. Steric and electronic influences that determine the relative reactivities of sulfonium salts have been examined computationally at B3LYP level of theory by calculating the energy of exchange of electrofuges with different substituents between THT and dimethyl sulfide. Because of more efficiently delocalized positive charge in THT moiety, tetrahydrothiophenium ions are more stable than the corresponding dimethylsulfonium ions, regardless of an electrofuge. The Hammond–Leffler coefficient is negative (α < 0) for the rate determining heterolysis of sulfonium salts 1 and 2. Copyright © 2011 John Wiley & Sons, Ltd.

Do the solvolysis reactions of secondary substrates occur by the SN1 or SN2 mechanism: or something else?

Primary and methyl aliphatic halides and tosylates undergo substitution reactions with nucleophiles in one step by the classic SN2 mechanism, which is characterized by second-order kinetics and inversion of configuration at the reaction center. Tertiary aliphatic halides and tosylates undergo substitution reactions with nucleophiles in two (or more) steps by the classic SN1 mechanism, which is characterized by first-order kinetics and incomplete inversion of configuration at the reaction center due to the presence of ion pairs. When the nucleophile is also the solvent, the substitution reaction is called a solvolysis, and both the SN2 and SN1 reactions now obey first-order kinetics. Schleyer and Bentley have provided solid, but not conclusive, evidence that secondary substrates undergo solvolysis by a merged mechanism, one that blends characteristics of both the SN2 and SN1 mechanisms. The following paper presents the history of their sustained pursuit of a merged mechanism and subsequent rebuttals to this claim. Several issues related to the philosophy and sociology of science are also discussed.

Liquid Ammonia as a Dipolar Aprotic Solvent for Aliphatic Nucleophilic Substitution Reactions

The rate constants for the reactions of a variety of nucleophiles reacting with substituted benzyl chlorides in liquid ammonia (LNH(3)) have been determined. To fully interpret the associated linear free-energy relationships, the ionization constants of phenols ions in liquid ammonia were obtained using UV spectra. These equilibrium constants are the product of those for ion-pair formation and dissociation to the free ions, which can be separated by evaluating the effect of added ammonium ions. There is a linear relationship between the pK(a) of phenols in liquid ammonia and those in water of slope 1.68. Aminium ions exist in their unprotonated free base form in liquid ammonia and their ionization constants could not be determined by NMR. The rates of solvolysis of substituted benzyl chlorides in liquid ammonia at 25 °C show a Hammett ρ of zero, having little or no dependence upon ring substituents, which is in stark contrast with the hydrolysis rates of substituted benzyl halides in water, which vary 10(7) fold. The rate of substitution of benzyl chloride by substituted phenoxide ions is first order in the concentration of the nucleophile indicative of a S(N)2 process, and the dependence of the rate constants on the pK(a) of the phenol in liquid ammonia generates a Brønsted β(nuc) = 0.40. Contrary to the solvolysis reaction, the reaction of phenoxide ion with 4-substituted benzyl chlorides gives a Hammett ρ = 1.1, excluding the 4-methoxy derivative, which shows the normal positive deviation. The second order rate constants for the substitution of benzyl chlorides by neutral and anionic amines show a single Brønsted β(nuc) = 0.21 (based on the aqueous pK(a) of amine), but their dependence on the substituent in substituted benzyl chlorides varies with a Hammett ρ of 0 for neutral amines, similar to that seen for solvolysis, whereas that for amine anions is 0.93, similar to that seen for phenoxide ion.

Luminescence properties of the Cu4I62− cluster

Two new solvates were prepared in the system Cu(I)I using a solvolysis reaction. The structures for both of them were solved by X-ray crystallography, showing that they constitute two modifications of the same compound with the net formula [Cu4I6](P(C6H5)4)2·2OC(CH3)2. Both types of crystals show vivid fluorescence when exposed to UV light. The formation of the first modification (I) seems to be preferred by kinetics and on ageing in the mother liquor it converts to modification (II). The Cu positions in (I) are disordered while those in (II) are fully ordered. The luminescent properties of both crystals were characterized using a confocal microscope and an excitation wavelength of 405 nm, resulting in fluorescence spectra with the intensities of 1.22 and 0.52 relative to the reference (fluorescein 10 µM). Density functional theory calculations on the ordered Cu4I62− core of modification (II) show that the de-excitation from LUMO to HOMO is responsible for the luminescence. The calculated emission spectrum has a maximum at 531 nm in good agreement with the results from confocal microscopy.

Mechanistic and Computational Study of a Palladacycle-Catalyzed Decomposition of a Series of Neutral Phosphorothioate Triesters in Methanol

The methanolytic cleavage of a series of O,O-dimethyl O-aryl phosphorothioates (1a−g) catalyzed by a C,N-palladacycle, (2-[N,N-dimethylamino(methyl)phenyl]-C1,N)(pyridine) palladium(II) triflate (3), at 25 °C and sspH 11.7 in methanol is reported, along with data for the methanolytic cleavage of 1a−g. The methoxide reaction gives a linear log k2−OMe vs sspKa (phenol leaving group) Brønsted plot having a gradient of βlg = −0.47 ± 0.03, suggesting about 34% cleavage of the P−OAr bond in the transition state. On the other hand, the 3-catalyzed cleavage of 1 gives a Brønsted plot with a downward break at sspKa (phenol) 13, signifying a change in the rate-limiting step in the catalyzed reaction, with the two wings having βlg values of 0.0 ± 0.03 and −1.93 ± 0.06. The rate-limiting step for good substrates with low leaving group sspKa values is proposed to be substrate/pyridine exchange on the palladacycle, while for substrates with poor leaving groups, the rate-limiting step is a chemical one with extensive cleavage of the P−OAr bond. DFT calculations support this process and also identify two intermediates, namely, one where substrate/pyridine interchange has occurred to give the palladacycle coordinated to substrate through the S═P linkage and to methoxide (6) and another where intramolecular methoxide attack has occurred on the P═S unit to give a five-coordinate phosphorane (7) doubly coordinated to Pd via the S− and through a bridging methoxide linked to P and Pd. Attempts to identify the existence of the phosphorane by 31P NMR in a d4-methanol solution containing 10 mM each of 3, trimethyl phosphorothioate (a very slow cleaving substrate), and methoxide proved unsuccessful, instead showing that the phosphorothioate was slowly converted to trimethyl phosphate, with the palladacycle decomposing to Pd0 and free pyridine. These results provide the first reported example where a palladacycle-promoted solvolysis reaction exhibits a break in the Brønsted plot signifying at least one intermediate, while the DFT calculations provide further insight into a more complex mechanism involving two intermediates.

Solvolysis of Substituted Benzoyl Chlorides in Nonionic and Mixed Micellar Solutions

The solvolysis of substituted benzoyl chlorides is sensitive both to substituent electronic effects and to medium effects. The solvolysis reactions of substituted benzoyl chlorides have been analyzed in the presence of nonionic micelles. The reaction is inhibited or catalyzed depending on the reaction mechanism, dissociative or associative, respectively. The micellar effects observed can be related to the low water content and low polarity of the interface as well as an increase of the nucleophilic character of the interfacial water. Moreover, the effect of the micellar surface charge on the solvolysis mechanism with high associative character was systematically studied. Mixed micelles of nonionic-ionic surfactants with a variable ionic content were prepared and characterized regarding charge and polarity. A correlation between the net charge of the micelles and the rate constants at the micellar interface was observed. The results suggest that the transient state for this mechanism is highly stabilized in a positively charged environment while the negative surface given by anionic micelles strongly inhibit the solvolysis reaction.

Solvolytic Reactivity of 2,4‐Dinitrophenolates

AbstractA series of X,Y‐substituted benzhydryl 2,4‐dinitrophenolates (DNP, 1–5) were subjected to solvolysis in various methanol/water, ethanol/water, and acetone/water mixtures at 25 °C. The linear free energy relationship (LFER) equation, log k = sf(Ef + Nf), was used to derive the nucleofuge‐specific parameters (Nf and sf) for an SN1‐type reaction. The magnitudes of nucleofugalities (Nf) are around zero, indicating that DNP falls in the middle of the established nucleofugality scale. The slope parameters (sf) and the Grünwald–Winstein mOTs parameters obtained demonstrate that benzhydryl DNPs solvolyze through a late transition state (TS) in which the negative charge delocalization causes considerably diminished solvation. Because of the late TS, the nucleofuge‐specific slope parameters, sf, are relatively high, i.e., the log k vs. Ef plots are steeper than for most of the previously investigated leaving groups. This may lead to intersection of the log k vs. Ef plots that correspond to DNP and to some other leaving groups of similar reactivity, i.e., inversion of the relative reactivities may occur. Such inversion is shown here for DNPs and phenyl carbonates.

ChemInform Abstract: The Stability of Bridgehead and Rigid Tertiary Carbenium Ions in the Gas Phase and Their Rate of Formation in Solvolysis Reactions.

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Dynamics for reactions of ion pairs in aqueous solution: reactivity of tosylate anion ion paired with the highly destabilized 1‐(4‐methylphenyl)‐2,2,2‐trifluoroethyl carbocation

The sum of the rate constants for solvolysis and scrambling of carbon bridging and nonbridging oxygen-18 at 4-MeC(6)H(4)CH(CF(3))OS((18)O(2))Tos in 50/50 (v/v) trifluoroethanol/water, (k(solv) + k(iso)) = 5.4 × 10(-6) s(-1), is 50% larger than k(solv) = 3.6 × 10(-6) for the simple solvolysis reaction of the sulfonate ester. This shows that the ion pair intermediate of solvolysis undergoes significant internal return to form reactant. These data give a value of k(-1) = 1.7 × 10(10) s(-1) for internal return of the carbocation-anion pair to the substrate. This rate constant is larger than the value of k(-1) = 7 × 10(9) s(-1) reported for internal return of an ion pair between the 1-(4-methylphenyl)ethyl carbocation and pentafluorobenzoate anion to the neutral ester (4-MeC(6)H(4)CH(CH(3))O(2)CC(6)F(5)) in the same solvent. The partitioning of ion pairs to the 1-(4-methylphenyl)ethyl carbocation and to the highly destabilized 1-(4-methylphenyl)2,2,2-trifluoroethyl carbocation is compared and contrasted.

ChemInform Abstract: Stereoselective Total Synthesis of the Pseudopterolide Kallolide A.

A total synthesis of the pseudopterolides, kallolide A (36) and kallolide A acetate (35), has been achieved. The racemic forms were prepared from the syn adduct 20 of furan 13 and stannane 17 (BF(3).OEt(2)-promoted addition) via the 15-membered propargylic allylic ether 25. [2,3]Wittig ring contraction led to the cis, anti, cis product 26. Alcohol 26 was transformed to butenolide 34 with net retention of configuration by Pd(PPh(3))(4)-catalyzed carbonylation of the mesylate 27 and ensuing AgNO(3)-catalyzed cyclization of the derived allenic acid 29. Solvolysis of the SEM ether (at C2) 34 in acetic acid or aqueous t-BuOH afforded racemic kallolide A acetate (35) and kallolide A (36), respectively, with inversion of stereochemistry by an S(N)1 process. Key elements of stereocontrol, including the steric outcome of the [2,3]Wittig ring contraction, the allenic ester isomerization, and the solvolysis reactions, were predicted from molecular mechanics calculations. The C8 and C2 epimers 45 and 46 of the cis, anti, cis kallolide A SEM ether precursor 34 were also prepared. The synthetic route originated from the anti adduct 19 of aldehyde 13 and the allylic chloride 16 and CuCl (cat), HSiCl(3), and i-Pr(2)NEt. Adduct 19 was subjected to the same sequence as the syn counterpart 20 to produce the trans, anti, cis [2,3]Wittig ring contraction product 42. The derived allenoate 44 afforded a 1:1 mixture of butenolides 45 and 46 upon sequential treatment with TBAF and AgNO(3). Finally, the natural enantiomer (+)-36 of kallolide A was synthesized from the enantioenriched syn adduct (+)-20, prepared by addition of allylic stannane 17 to aldehyde 13 promoted by a modified chiral acyloxyborane Lewis acid.

Influence of the oxygen atom acceptor on the reaction coordinate and mechanism of oxygen atom transfer from the dioxo-Mo(VI) complex, Tp(iPr)MoO(2)(OPh), to tertiary phosphines.

The oxygen atom transfer reactivity of the dioxo-Mo(VI) complex, Tp(iPr)MoO(2)(OPh) (Tp(iPr) = hydrotris(3-isopropylpyrazol-1-yl)borate), with a range of tertiary phosphines (PMe(3), PMe(2)Ph, PEt(3), PBu(n)(3), PEt(2)Ph, PEtPh(2), and PMePh(2)) has been investigated. The first step in all the reactions follows a second-order rate law indicative of an associative transition state, consistent with nucleophilic attack by the phosphine on an oxo ligand, namely, Tp(iPr)MoO(2)(OPh) + PR(3) --> Tp(iPr)MoO(OPh)(OPR(3)). The calculated free energy of activation for the formation of the OPMe(3) intermediate (Chem. Eur. J. 2006, 12, 7501) is in excellent agreement with the experimental DeltaG() value reported here. The second step of the reaction, that is, the exchange of the coordinated phosphine oxide by acetonitrile, Tp(iPr)MoO(OPh)(OPR(3)) + MeCN --> Tp(iPr)MoO(OPh)(MeCN) + OPR(3), is first-order in starting complex in acetonitrile. The reaction occurs via a dissociative interchange (I(d)) or associative interchange (I(a)) mechanism, depending on the nature of the phosphine oxide. The activation parameters for the solvolysis of Tp(iPr)MoO(OPh)(OPMe(3)) (DeltaH(++) = 56.3 kJ mol(-1); DeltaS(++) = -125.9 J mol(-1) K(-1); DeltaG(++) = 93.8 kJ mol(-1)) and Tp(iPr)MoO(OPh)(OPEtPh(2)) (DeltaH(++) = 66.5 kJ mol(-1); DeltaS(++) = -67.6 J mol(-1) K(-1); DeltaG(++) = 86.7 kJ mol(-1)) by acetonitrile are indicative of I(a) mechanisms. In contrast, the corresponding parameters for the solvolysis reaction of Tp(iPr)MoO(OPh)(OPEt(3)) (DeltaH(++) = 95.8 kJ mol(-1); DeltaS(++) = 26.0 J mol(-1) K(-1); DeltaG(++) = 88.1 kJ mol(-1)) and the remaining complexes by the same solvent are indicative of an I(d) mechanism. The equilibrium constant for the solvolysis of the oxo-Mo(V) phosphoryl complex, [Tp(iPr)MoO(OPh)(OPMe(3))](+), by acetonitrile was calculated to be 1.9 x 10(-6). The oxo-Mo(V) phosphoryl complex is more stable than the acetonitrile analogue, whereas the oxo-Mo(IV) acetonitrile complex is more stable than the phosphoryl analogue. The higher stability of the Mo(V) phosphoryl complex may explain the phosphate inhibition of sulfite oxidase.

Salt Effects on the Rates and Mechanisms of Solvolysis Reaction of Organic Halides and Water Structure Distortion in N,N-Dimethylformamide– and N,N-Dimethylacetamide–Water Mixed Solvents

Abstract In 50% (v/v) DMF– and DMA–H2O mixed solvents, salt effects on the solvolysis reaction rates of aliphatic halides and related compounds (RX) have been examined for further exploring. Compared with previous results obtained in other organic solvent systems, such as 50% (v/v) acetone–, 1,4-dioxane–, or sulfolane–H2O, no exceptional behavior was observed in the “pseudo” first-order rate constants (k/s−1) of all the typical SN1 and SN2 substrates by the addition of alkali metal and alkaline earth metal perchlorates or many kinds of tetraalkylammonium salts in 50% (v/v) DMF– and DMA–H2O mixed solvents. The detailed examination of Δlog(k/s−1)/Δ[LiClO4] for 1-adamantyl bromide vs. the contents of organic solvents (CH3CN, DMA, and DMSO) suggested that the observed different salt effects were caused by the different solvation abilities of the solvents toward the leaving-group anion as well as the metal cation. As a new highlight in the present paper, we were able to demonstrate a proportionality or correlation between the LiClO4 effects in the solvolysis rates and the carbocation stabilities expressed by the Gibbs free energy values (ΔGo) of RX in the gas phase. Based on the Raman spectra of DMA–H2O and DMA–D2O as well as DMF–D2O mixed solvents, we discuss the distortion of the bulk water structure.

A Detailed Study of Sulfonate Ester Formation and Solvolysis Reaction Rates and Application toward Establishing Sulfonate Ester Control in Pharmaceutical Manufacturing Processes

Sulfonate esters of lower alcohols possess the capacity to react with DNA and cause mutagenic events, which in turn may be cancer inducing. Consequently, the control of residues of such substances in products that may be ingested by man (in food or pharmaceuticals) is of importance to both pharmaceutical producers and to regulatory agencies. Given that a detailed study of sulfonate ester reaction dynamics (mechanism, rates, and equilibria) has not been published to date, a detailed kinetic and mechanistic study was undertaken and is reported herein as a follow-up to our earlier communication in this journal. The study definitively demonstrates that sulfonate esters cannot form even at trace level if any acid present is neutralized with even the slightest excess of base. A key conclusion from this work is that the high level of regulatory concern over the potential presence of sulfonate esters in API sulfonate salts is largely unwarranted and that sulfonate salts should not be shunned by innovator pharmace...

Kinetics of the Solvolyses of Fluoro‐Substituted Benzhydryl Derivatives: Reference Electrofuges for the Development of a Comprehensive Nucleofugality Scale

AbstractA series of m‐fluoro‐substituted benzhydryl chlorides, bromides, mesylates, and tosylates 1‐X to 5‐X were prepared and subjected to solvolysis reactions in various solvents. The observed first‐order rate constants ks(25 °C) were found to follow the correlation equation log ks(25 °C) = sf(Nf + Ef), which allowed us to determine the electrofugality parameters Ef for these destabilized benzhydrylium cations and the nucleofugality parameters Nf, sf for a series of leaving group/solvent combinations.

Supramolecular Catalysis by Cucurbit[7]uril and Cyclodextrins: Similarity and Differences

To understand the analogies and differences between the cucurbituril and cyclodextrin cavities different solvolytic reactions have been studied in the presence of cucurbit[7]uril, CB7, and beta-CD or its methylated derivative, DM-beta-CD. Solvolysis of 1-bromoadamantane has been used as a test to evaluate the ability of the cavities to solvate the Br(-) leaving group. Obtained results show that in both cases the polarity inside the cavity is similar to that of a 70% ethanol:water mixture. Solvolysis of substituted benzoyl chlorides shows a great difference between the CB7 and DM-beta-CD cavity. Solvolysis of electron withdrawing substituted benzoyl chlorides (associative mechanism) is catalyzed by DM-beta-CD and inhibited by CB7. However, solvolysis of electron donating substituted benzoyl chlorides (dissociative mechanism) is catalyzed by CB7 and inhibited by DM-beta-CD. These experimental behaviors have been explained on the basis of different solvolytic mechanisms. Participation of the hydroxyl groups of the cyclodextrin as a nucleophile can explain the catalytic effect observed for solvolysis of benzoyl chlorides reacting by an associative mechanism. Solvolysis of benzoyl chlorides reacting by a dissociative mechanism is catalyzed by CB7 due to the ability of the CB7 cavity to stabilize the acylium ion developed in the transition state by electrostatic interactions.

Ultrafast time-resolved transient infrared and resonance Raman spectroscopic study of the photo-deprotection and rearrangement reactions of p-hydroxyphenacyl caged phosphates

This is a picosecond and nanosecond time-resolved infrared absorption spectroscopic study of p-hydroxphenacyl diethylphosphate (HPDP) in aqueous solution examining the deprotection reaction and subsequent evolution to produce the p-hydroxyphenylacetic acid (HPAA) rearrangement product. The data reported here support previous ultrafast fluorescence, Raman and transient UV/visible absorption studies and provide new insight into the role of water in the deprotection reaction. It also provides insight into the nature of the intermediate steps that take place following initial formation of the triplet state and its reaction with water to eventually produce the solvent-separated ions and solvolytic reaction product HPAA. In addition, density functional theory (DFT) calculations were performed to investigate the reactions of the triplet state of HPDP with water molecules to induce deprotection, the formation of a contact ion pair and the subsequent intermediates that lead to the HPAA rearrangement product. A more detailed reaction mechanism is proposed based on the time-resolved spectroscopy experiments and DFT computational results.

An application of second-order UV-derivative spectrophotometry for study of solvolysis of a novel fluocinolone acetonide ester

A novel topical corticosteroid FA-21-PhP, 2-phenoxypropionate ester of fluocinolone acetonide, has been synthesized in order to investigate the possibility of decreasing systemic side effects. In this study model system for in vitro solvolytic reaction of FA-21-PhP has been analyzed in ethanol/water (90:10, v/v) with excess of sodium hydrogen carbonate. The selected conditions have been used as in vitro model for activation of corticosteroid C-21 ester prodrug. The second-order derivative spectrophotometric method (DS) using zero-crossing technique was developed for monitoring ternary mixture of solvolysis. Fluocinolone acetonide (FA) as a solvolyte was determined in the mixture in the concentration range 0.062–0.312 mM using amplitude 2D 274.96. Experimentally determined LOD value was 0.0295 mM. The accuracy of proposed DS method was confirmed with HPLC referent method. Peak area of parent ester FA-21-PhP was used for solvolysis monitoring to ensure the initial stage of changes. Linear relationship in HPLC assay for parent ester was obtained in the concentration range 0.054–0.54 mM, with experimentally determined LOD value of 0.0041 mM. Investigated solvolytic reaction in the presence of excess of NaHCO 3 proceeded via a pseudo-first-order kinetic with significant correlation coefficients 0.9891 and 0.9997 for DS and HPLC, respectively. The values of solvolysis rate constant calculated according to DS and HPLC methods are in good accordance 0.038 and 0.043 h −1, respectively.

Solvolysis reactions at the 13th carbon of 1-aryl organoiron complexes

Acid-catalysed solvolysis procedures exchange protecting groups on benzyl alcohol derivatives in the synthesis of η 5 1-arylcyclohexadienyliron building blocks for alkaloid synthesis. The reaction proceeds via a carbocation intermediate which can also be intercepted by intramolecular electrophilic addition to the tricarbonyl(η 4-diene)iron(0) moiety to provide a novel and high-yielding cyclisation reaction forming a 5aα-cyanomethyl-5a,8a-dihydrofluorene tricarbonyliron complex in 96% yield.

Kinetic Studies of the Solvolyses of 4-Nitrophenyl Phenyl Thiophosphorochloridate

Rates of solvolyses of 4-nitrophenyl phenyl thiophosphorochloridate (4-N<TEX>$O_2$</TEX>PhOP(S)(Cl)OPh, <TEX>$\underline{1}$</TEX>) in ethanol, methanol, and aqueous binary mixtures incorporating ethanol, methanol, acetone, and 2,2,2-trifluroethanol (TFE) are reported. Thermodynamic parameters were determined at several temperatures in three representative solvents. The extended Grunwald-Winstein equation was applied to 29 solvents and the correlation coefficient (R) showed 0.959. The sensitivities (l = 1.37 and m = 0.62) are similar to those obtained for diphenyl thiophosphorochloridate ((<TEX>$PhO)_2$</TEX>PSCl, <TEX>$\underline{2}$</TEX>), diphenyl phosphorochloridate ((<TEX>$PhO)_2$</TEX>POCl, <TEX>$\underline{3}$</TEX>), diphenyl phosphinic chloride (<TEX>$Ph_2$</TEX>POCl, <TEX>$\underline{4}$</TEX>), and diphenyl thiophosphinic chloride (<TEX>$Ph_2$</TEX>PSCl, <TEX>$\underline{5}$</TEX>). The solvolytic reaction mechanism of 4-nitrophenyl phenyl thiophosphorochloridate (<TEX>$\underline{1}$</TEX>) is suggested to be proceeded a <TEX>$S_N$</TEX>2 process as previously reported result. The activation enthalpies are shown as slightly low as <TEX>${\Delta}H^{\neq}\;=\;9.62\;to\;11.9\;kcal{\cdot}mol^{-1}$</TEX> and the activation entropies are shown as slightly high negative value as <TEX>${\Delta}S^{\neq}\;=\;-34.1\;to\;-44.9\;cal{\cdot}mol^{-1}{\cdot}K^{-1}$</TEX> compared to the expected <TEX>$S_N$</TEX>2 reaction mechanism. Kinetic solvent isotope effects are accord with a typical <TEX>$S_N$</TEX>2 mechanism as shown in the range of 2.41 in MeOH/ MeOD and 2.57 in <TEX>$H_2O/D_2O$</TEX> solvent mixtures.