A solvent is at least partially separated from a catalyst. The catalyst comprises nickel and a bidentate phosphorus-containing ligand. The method for separation involves distilling a catalyst solution. The ratio of 2-pentenenitrile to 3-pentenenitrile in distillation column bottoms is controlled to reduce the amount of 3-pentenenitrile which is isomerized to form 2-methyl-3-butenenitrile. Isomerization of 3-pentenenitrile to 2-methyl-3-butenenitrile and subsequent isomerization of 2-methyl-3-butenenitrile to 2-methyl-2-butenenitrile, and/or hydrocyanation of 2-methyl-3-butenenitrile to methylglutaronitrile represents a loss in adiponitrile yield in a process for making adiponitrile.

A solvent is at least partially separated from a catalyst. The catalyst comprises nickel and a bidentate phosphorus-containing ligand. The method for separation involves distilling a catalyst solution. The ratio of 2-pentenenitrile to 3-pentenenitrile in distillation column bottoms is controlled to reduce the amount of 3-pentenenitrile which is isomerized to form 2-methyl-3-butenenitrile. Isomerization of 3-pentenenitrile to 2-methyl-3-butenenitrile and subsequent isomerization of 2-methyl-3-butenenitrile to 2-methyl-2-butenenitrile, and/or hydrocyanation of 2-methyl-3-butenenitrile to methylglutaronitrile represents a loss in adiponitrile yield in a process for making adiponitrile.

The present invention provides an electrolytic solution capable of providing an electrochemical device (e.g., a lithium ion secondary battery) or a module that is less likely to generate gas even in high-temperature storage and has high capacity retention even after high-temperature storage. The present invention relates to an electrolytic solution which may contain a compound represented by Y.sup.21R.sup.21CCY.sup.22R.sup.22 wherein R.sup.21 and R.sup.22 may be the same as or different from each other, and are each H, an alkyl group, or a halogenated alkyl group; Y.sup.21 and Y.sup.22 may be the same as or different from each other, and are each OR.sup.23 or a halogen atom; and R.sup.23 is H, an alkyl group, or a halogenated alkyl group.

The present invention provides an electrolytic solution capable of providing an electrochemical device (e.g., a lithium ion secondary battery) or a module that is less likely to generate gas even in high-temperature storage and has high capacity retention even after high-temperature storage. The present invention relates to an electrolytic solution which may contain a compound represented by Y.sup.21R.sup.21CCY.sup.22R.sup.22 wherein R.sup.21 and R.sup.22 may be the same as or different from each other, and are each H, an alkyl group, or a halogenated alkyl group; Y.sup.21 and Y.sup.22 may be the same as or different from each other, and are each OR.sup.23 or a halogen atom; and R.sup.23 is H, an alkyl group, or a halogenated alkyl group.

The present application provides an electrolyte and an electrochemical device. The electrolyte according to the present application comprises a carboxylate, a barbituric acid compound and a nitrile compound. Adding a barbituric acid compound and a nitrile compound of particular structure to an electrolyte containing a carboxylate solvent can significantly improve the rate performance of an electrochemical device, and mitigate capacity loss after storage at room temperature, and cycle fading and gas generation at high-temperature of the electrochemical device.

The present application provides an electrolyte and an electrochemical device. The electrolyte according to the present application comprises a carboxylate, a barbituric acid compound and a nitrile compound. Adding a barbituric acid compound and a nitrile compound of particular structure to an electrolyte containing a carboxylate solvent can significantly improve the rate performance of an electrochemical device, and mitigate capacity loss after storage at room temperature, and cycle fading and gas generation at high-temperature of the electrochemical device.

The present application relates to the field of energy storage materials, and particularly, to an electrolytic solution and a battery using the electrolytic solution. The electrolytic solution of the present application contains an additive, the additive including a multi-cyano compound represented by formula (I). The multi-cyano compound of the present application has a stronger complexation with a transition metal on the surface of a positive electrode material, and therefore a protective film can be formed on the surface of the positive electrode material, and the dissolution of the transition metal is effectively suppressed; the surface activity of the positive electrode material is reduced, thereby suppressing side reactions, such as the decomposition of the electrolytic solution on the surface of the positive electrode material; and the cycle performance and storage performance of a battery under wide range of working voltage and wide range of operating temperature conditions are thus improved.

##STR00001##

The present application relates to the field of energy storage materials, and particularly, to an electrolytic solution and a battery using the electrolytic solution. The electrolytic solution of the present application contains an additive, the additive including a multi-cyano compound represented by formula (I). The multi-cyano compound of the present application has a stronger complexation with a transition metal on the surface of a positive electrode material, and therefore a protective film can be formed on the surface of the positive electrode material, and the dissolution of the transition metal is effectively suppressed; the surface activity of the positive electrode material is reduced, thereby suppressing side reactions, such as the decomposition of the electrolytic solution on the surface of the positive electrode material; and the cycle performance and storage performance of a battery under wide range of working voltage and wide range of operating temperature conditions are thus improved.

##STR00001##

Disclosed is a method for inhibiting the formation of by-products from dinitriles, such as the formation of cyclopentylideneimine (CPI) from Adiponitrile (ADN), comprising adding an effective amount of a Brnsted acid to the ADN. Also disclosed is a method of refining a dinitrile compound by distillation the method comprising the steps of: (a) supplying (i) a feedstream comprising the dinitrile compound and (ii) a Brnsted acid to a distillation apparatus; and (b) withdrawing from the distillation apparatus an overhead distillate stream comprising the dinitrile compound.

Disclosed is a method for inhibiting the formation of by-products from dinitriles, such as the formation of cyclopentylideneimine (CPI) from Adiponitrile (ADN), comprising adding an effective amount of a Brnsted acid to the ADN. Also disclosed is a method of refining a dinitrile compound by distillation the method comprising the steps of: (a) supplying (i) a feedstream comprising the dinitrile compound and (ii) a Brnsted acid to a distillation apparatus; and (b) withdrawing from the distillation apparatus an overhead distillate stream comprising the dinitrile compound.