A process for producing acetonitrile, the process comprising dehydrating a feedstock stream comprising acetonitrile, acrylonitrile, allyl alcohol, and water (and optionally methanol) in a dehydration (first) column to yield a dehydrated acetonitrile stream comprising acetonitrile and acrylonitrile, less than 1 wt % allyl alcohol, and less than 50 wt % water, and optionally hydrogen cyanide; distilling the dehydrated acetonitrile stream in a lights (second) column to yield a distillate stream comprising lights, and a bottoms stream comprising acetonitrile, acrylonitrile, water, and optionally hydrogen cyanide and acrylonitrile; extracting the distillation bottoms stream in an extraction (third) column to yield a raffinate stream comprising acetonitrile and less than 200 ppm acrylonitrile and an extract stream comprising water and acrylonitrile; purifying the raffinate stream to yield a product acetonitrile stream.

A process for producing acetonitrile, the process comprising dehydrating a feedstock stream comprising acetonitrile, acrylonitrile, allyl alcohol, and water (and optionally methanol) in a dehydration (first) column to yield a dehydrated acetonitrile stream comprising acetonitrile and acrylonitrile, less than 1 wt % allyl alcohol, and less than 50 wt % water, and optionally hydrogen cyanide; distilling the dehydrated acetonitrile stream in a lights (second) column to yield a distillate stream comprising lights, and a bottoms stream comprising acetonitrile, acrylonitrile, water, and optionally hydrogen cyanide and acrylonitrile; extracting the distillation bottoms stream in an extraction (third) column to yield a raffinate stream comprising acetonitrile and less than 200 ppm acrylonitrile and an extract stream comprising water and acrylonitrile; purifying the raffinate stream to yield a product acetonitrile stream.

A preparation method of 1-(4-aminophenyl)cyclopentanecarbonitrile includes the following steps: step 1: in the presence of Li.sub.2CuCl.sub.4, adding a nitrochlorobenzene-zinc reagent dropwise to a 1-chlorocyclopentanecarbonitrile solution to prepare a compound 1-(4-nitrophenyl)cyclopentanecarbonitrile; and step 2: subjecting the compound 1-(4-nitrophenyl)cyclopentanecarbonitrile obtained in step 1 to a nitroreduction reaction under the action of a catalyst to prepare the compound 1-(4-aminophenyl)cyclopentanecarbonitrile. The preparation method involves cheap and easily-available raw materials, mild reaction conditions, and convenient operations, leads to high yield, and is environmentally-friendly and suitable for industrial large-scale production.

A preparation method of 1-(4-aminophenyl)cyclopentanecarbonitrile includes the following steps: step 1: in the presence of Li.sub.2CuCl.sub.4, adding a nitrochlorobenzene-zinc reagent dropwise to a 1-chlorocyclopentanecarbonitrile solution to prepare a compound 1-(4-nitrophenyl)cyclopentanecarbonitrile; and step 2: subjecting the compound 1-(4-nitrophenyl)cyclopentanecarbonitrile obtained in step 1 to a nitroreduction reaction under the action of a catalyst to prepare the compound 1-(4-aminophenyl)cyclopentanecarbonitrile. The preparation method involves cheap and easily-available raw materials, mild reaction conditions, and convenient operations, leads to high yield, and is environmentally-friendly and suitable for industrial large-scale production.

The present invention relates to alanine N-acetic acid precursors of formula (i) COOM-CH(CH3)-NH—(CH2CN), wherein M is hydrogen (alanine N-monoacetonitrile), or (ii) COOM-CH(CH3)-N—(CH2CN)2, wherein 0 to 50% of all M is sodium or potassium and 50 to 100% of all M is hydrogen (alanine N,N-diacetonitrile and its partial sodium or potassium salts) comprising L-alanine to D-alanine in a range of from 75:25 to 50:50 (L:D), or (iii) COOM-CH(CH3)-N—(CH2CONH2)2, wherein M is hydrogen (alanine N,N-diacetamide), in the form of crystals, and relates to a process to prepare these precursors and their use, especially to give MGMA or MGDA.

The present invention relates to alanine N-acetic acid precursors of formula (i) COOM-CH(CH3)-NH—(CH2CN), wherein M is hydrogen (alanine N-monoacetonitrile), or (ii) COOM-CH(CH3)-N—(CH2CN)2, wherein 0 to 50% of all M is sodium or potassium and 50 to 100% of all M is hydrogen (alanine N,N-diacetonitrile and its partial sodium or potassium salts) comprising L-alanine to D-alanine in a range of from 75:25 to 50:50 (L:D), or (iii) COOM-CH(CH3)-N—(CH2CONH2)2, wherein M is hydrogen (alanine N,N-diacetamide), in the form of crystals, and relates to a process to prepare these precursors and their use, especially to give MGMA or MGDA.

Novel crystal forms of (R)-(−)-verapamil hydrochloride are disclosed.

Novel crystal forms of (R)-(−)-verapamil hydrochloride are disclosed.

Novel crystal forms of (R)-(−)-verapamil hydrochloride are disclosed.

The present invention relates to a process for purifying adiponitrile (ADN), wherein crude ADN is introduced into a rectification apparatus (R1). The rectification apparatus (R1) comprises a first side draw and preferably also a second side draw, the first side draw being disposed below the crude ADN introduction point and the optional second side draw being disposed above the crude ADN introduction point. The first side draw is used to draw off a gaseous stream comprising ADN while the optional second side draw is used to draw off undesired by-products such as 1-amino-2-cyanocyclopentene (ACCP) which are often generated in ADN production and consequently may be present in the crude ADN. The gaseous stream from the first side draw of (R1) is introduced into a second rectification apparatus (R2). (R2) is used to separate off ADN from remaining high boilers and any other by-products present, pure ADN being drawn off from (D2) as overhead product. It is preferable when the process according to the invention employs crude ADN from a reaction of butadiene with hydrocyanic acid (HCN).