Process description: N‐Methyl‐2‐Pyrrolidone (NMP) Johnson Matthey’s technology generates high‐quality NMP by reacting gamma‐butyrolactone (GBL) and monomethylamine (MMA), which are products of our butanediol and methylamines processes, respectively. This NMP production route extends the value of two established DAVY™ technologies while offering feedstock flexibility and efficiency with product quality. The DAVY NMP flowsheet separately generates two compounds, gamma‐butyrolactone (GBL) and monomethylamine (MMA), before reacting them together to form NMP. Process feedstocks The process feedstock for producing GBL is molten maleic anhydride (MAH), obtainable by the oxidation of butane or benzene. The amination process, which yields the MMA reactant, requires liquid methanol and liquid ammonia, which mix with a composite stream of recycled methanol, ammonia and methylamines from downstream distillation. GBL production Molten maleic anhydride reacts with methanol vapour in the DAVY esterification reaction column to produce liquid‐phase dimethyl maleate (DMM): Vapour‐phase hydrogenolysis follows to produce gamma‐butyrolactone (GBL): Some GBL also hydrolizes to butanediol (BDO), which subsequently dehydrates to tetrahydrofuran (THF). Distillation separates these compounds to yield high‐grade liquid GBL. Amination The amination feed stream, comprising methanol, ammonia and methylamines, passes through several heat exchangers, first vaporizing and then superheating before entering the methylamines converter. Here, the vapours pass over catalyst, facilitating an exothermic reaction between the methanol and ammonia to produce MMA, dimethylamine (DMA) and trimethylamine (TMA): Additional disproportionation and transmethylation reactions create amines from other amines. The hot vapour product stream exiting the converter contains the three methylamine products, reaction water and unreacted ammonia and methanol. The individual quantities of each amine produced are determined by the converter’s feed composition. This in turn is a function of the amounts of each reactant and methylamine product recycled from distillation to join the fresh methanol and ammonia feed. After passing through a heat recovery system and then a condenser, the process stream, now a liquid, progresses to the distillation stage. Distillation The distillation system, comprising a number of columns in series, purifies and separates the crude methylamine products firstly by separating unreacted ammonia and recycling it to the amination stage. Subsequent distillation then produces a pure anhydrous MMA stream which proceeds to NMP conversion, and water‐free DMA and TMA streams that recycle back to amination. Residual methanol is extracted from the water and also recycles to the amination stage. NMP synthesis Stoichiometric quantities of GBL and MMA proceed to the specialized NMP synthesis reactor, in which they undergo non‐catalyzed liquid‐phase reaction. The reaction takes place in two stages. First, the GBL and MMA combine to form a long‐chain amide by cleavage of the GBL ring and attachment of the MMA. The resulting intermediate is 4‐hydroxy‐n‐
methylbutylamide (HMB): In the second stage, cyclisation restores the cyclic molecular structure as the HMB molecule dehydrates to form NMP: Purification and separation Distillation separates organic heavies, MMA and reaction water to yield solvent‐quality NMP, which is sent to storage. The reaction heavies and MMA are recycled back to synthesis. Process option: anhydrous or aqueous feed The DAVY NMP process can utilize either anhydrous or aqueous MMA feedstock. The Johnson Matthey advantage The DAVY NMP process utilizes our world‐leading technologies from our butanediol and methylamines processes. Johnson Matthey’s use of esterification prior to hydrogenolysis has transformed fatty alcohol production. The benefits of this innovation are numerous, from reduced capital costs to milder, safer operating conditions and improved conversion. Low material and equipment costs 
The esterification step neutralizes the acidic feed. This enables the hydrogenolysis and refining systems to be made of inexpensive carbon steel. Net savings over conventional processes 
The combined savings of cheaper construction materials and catalysts more than compensate for the cost of the added esterification step. 
For improved efficiency and reduced operating costs, the amination process includes a heat recovery system that recycles exothermic reaction heat to the incoming feed streams. This reduces required energy input. Optimized heat integration 
Lower environmental impact 
Flowsheet includes numerous features to prevent atmospheric emissions and to ensure the plant should fall within legislative limits worldwide. 
Simplified catalysis, process efficiency The esterification and hydrogenolysis catalysts remain in their respective reaction vessels, eliminating the need for catalyst separation and neutralization at any stage of the process. The esterification catalyst can also be changed at 100% load without any downtime or loss of production. 
Low‐cost, higher‐
performance catalyst 
The non‐acidic hydrogenolysis environment also allows use of a base‐metal catalyst instead of a high‐grade precious metal catalyst. This delivers superior performance at lower cost. Easy process integration 
Our process can easily integrate with maleic anhydride facilities which use abundant, low‐cost butane feedstock as their raw material. Large capacities 
High process output available in a single train. The information contained within this document was previously published on a former DAVYTM website. Information contained in this publication or as otherwise supplied to Users is believed to be accurate and correct at time of going to press, and is given in good faith, but it is for the User to satisfy itself of the suitability of the Product for its own particular purpose. Johnson Matthey plc (JM) gives no warranty as the fitness of the Product for any particular purpose and any implied warranty or condition (statutory or otherwise) is excluded except to the extent that exclusion is prevented by law. JM accepts no liability for loss or damage (other than that arising from death or personal injury caused by JM’s negligence or by a defective Product, if proved), resulting from reliance on this information. Freedom under Patent, Copyright and Designs cannot be assumed. Johnson Matthey Davy Technologies Limited, Registered Office 5th Floor 25 Farringdon Street London EC4A 4AB Registered in England No. 635311 Offices worldwide. For contact details please visit our website.
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