Heats of combustion of DI (n-butylamino)n-butylborane and tri(n-butylamino)borane

Conclusions Di(n-butylamino)n-butylborane and tri(n-butylamino)borane were synthesized; their heats of combustion were determined and their standard heats of formation were calculated.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 200–202, January, 1973. Original article submitted April 6, 1972.     

Reactivity of α-amino acids at their arenesulfonation in the water-1,4-dioxane and water-2-propanol systems

The kinetics of arenesulfonation of D,L-threonine, D,L-leucine and L-isoleucine with 3-nitrobenzenesulfonyl chloride in the water-1,4-dioxane and water-2-propanol solvents in the temperature range 298-313 K was studied. Calculations of effective values of activation parameters of reactions were carried out. Kinetic parameters of the studied processes were compared with the results of previous studies of the reaction of acyl transfer involving α-amino acids.     

Nonlinear differential algebraic equations

We consider a system of nonlinear ordinary differential equations that are not solved with respect to the derivative of the unknown vector function and degenerate identically in the domain of definition. We obtain conditions for the existence of an operator transforming the original system to the normal form and prove a general theorem on the solvability of the Cauchy problem.     

Stability of Differential-Algebraic Equations under Uncertainty

We consider a linear time-invariant homogeneous system of first-order ordinary differential equations with a noninvertible matrix multiplying the derivative of the unknown vector function and with perturbed coefficients. We introduce a class of perturbations of the coefficient matrices of the system and determine conditions on the perturbations of this class under which they do not affect the internal structure of the system. We obtain sufficient conditions for the robust stability of the system under such perturbations.