Factors effecting the freeze thaw process in soils and reduction in damage due to frosting with reinforcement: a review

Magnetic mesocellular foams with nickel complexes: as efficient and reusable nanocatalysts for the synthesis of symmetrical and asymmetrical diaryl chalcogenides

“…To investigate the chemoselectivity of this method, the reaction of 1-bromo-4-chlorobenzene (as a dihalogenated aryl halide) was performed with triphenyltin chloride and Se; bromide showed a higher reaction (Table 5, entry 10). Although the exact mechanism for the C-Se bond formation via reaction of aryl halides with triphenyltin chloride and Se in the presence of MCF@Met-Ni nanocatalyst is not clear at this time, based on the previously reported mechanisms for C-S bond formation using aryl halide, triphenylene chloride and sulfur powder [68][69][70] and C-Se coupling reaction using aryl halides and Se powder 71,72 the proposed mechanism for the synthesis of phenyl aryl selenides in the presence of M-MCF@Met-Ni nanocatalyst is presented in Scheme 3. First, K 2 CO 3 reacts with elemental Se to produce potassium diselenide, which reacts with M-MCF@Met-Ni to The desired product may be obtained by reductive elimination of intermediate 5.…”

Transition Metal‐Free Sulfenylation of C−H Bonds for C−S Bond Formation in Recent Years: Mechanistic Approach and Promising Future

“…These reactions are associated with the release of simpler by products i. e., H 2 and H 2 O. Attempts have been made to develop alternative sulfur surrogates such as S 8, [28] carbon disulfide (CS 2 ) , [29] potassium thiocyanate (KSCN), [30] dimethyl sulfoxide (DMSO), [31] sodium thiosulfate (NaS 2 O 3 ), [32] thiourea, [33] sulfonyl chlorides, thiols, Bunte salts, [55] sodium sulfinates, [56][57][58][59][60][61][62][63][64][65][66] N-(aryl/alkylsulfanyl)succinimides, [67] disulfides and sulfonyl hydrazides [68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84] as a sustainable sulfur source. The optimum usage of electrochemical and visible light in a metal-free approach is also important from green chemistry prespective.…”

“…Moreover, the intermediacy of pdi(tolyl)sulfide (2) was ruled out when its reaction with 1methoxynaphthalene failed to yield desired product. Finally, it was proposed that arylsulfonyl chloride (29) reacts with diethyl phosphite and gets reduced to intermediate arylsulfenyl chloride (30 A), followed by a nucleophilic attack of iodide ion on it resulted into arylsulfenyl iodide (ArSI) (30 B). Heat assisted dissociation of intermediate 26 A yield arylsulfenyl radical 5 F along with iodide radical.…”

Experimental Study on the Effects of Freeze-Thaw Progressions and Performance of Soil with Non-Toxic Bio-Enzyme

“…The compressive strength of soil reduces as the number of freeze and thaw cycles increases with time [7]. The variation in the soil organic matter under FTCS conditions has been affected by physical, chemical, and biological actions [8,9]. The strength of the destructive action is related to factors such as surface freezing temperature, freezing depth, freezing duration, and winter snowfall [10,11].…”

“…Freezing of soil moisture increases the volume and stiffness of soil, which results in cracking of the pavement structure. On the other hand, thawing melting of ice occurs, which results in consolidation settlement [8,18]. Frostsusceptible soils meet the condition of frost susceptibility; that is, the particle size should be more than the limit of 3% 􀅫iner than 20 mm.…”