Licensed Processes

Dimethylformamide (DMF)

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Introduction

This Davy flowsheet reacts dimethylamine (DMA) from our methylamines process with carbon monoxide (CO) to produce pure liquid dimethylformamide (DMF).

Our DMF process simply adds a reaction step to our proven methylamines technology to deliver a value-added and high-grade product. Alternatively, if a pre-existing DMA source is available, we can provide the flowsheet for stand-alone conversion to DMF.

Process Flowsheet

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Key Reactions

The simplified set of reactions below yield dimethylformamide.

The amination stage first converts methanol and ammonia to dimethylamine (DMA):

An exothermic reaction between liquid-phase DMA and carbon monoxide gas then produces the DMF product:

Process Description

The Davy DMF process comprises two main steps: vapour-phase methylamines production to yield the key reactant dimethylamine (DMA); then a homogeneously catalysed reaction of liquid DMA and CO gas to produce DMF.

Process feedstock

The process feedstocks are liquid methanol and liquid ammonia, which mix with a composite stream of methanol, ammonia and methylamines recycled from downstream distillation.

Amination

The feed stream passes through several heat exchangers, first vaporising 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 monomethylamine (MMA), DMA and trimethylamine (TMA):

Amination-equations-1

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 DMA stream which proceeds to DMF conversion, and water-free MMA and TMA steams that recycle back to amination.

Residual methanol is extracted from the water and also recycles to the amination stage.

DMF synthesis

Liquid DMA enters the reactor, which also contains catalyst. Carbon monoxide gas enters the vessel via jet nozzles, which creates the necessary turbulence for good reactant contact.

The overall exothermic reaction proceeds in two stages, the first being a slow reaction that forms the intermediate compound methylformate:

A fast reaction then yields DMF:

Purification and separation

The reactor product, a hot liquid, proceeds to the DMF vaporiser, which flashes DMF, unreacted DMA and methanol vapour from the catalyst solution.

Subsequent distillation and stripping steps then separate pure DMF liquid, with DMA and methanol recycling to the DMF reactor.

The JM Davy Advantage

By adding a simple reaction step to our world-leading methylamines (MA) process, the Davy DMF flowsheet further enhances our already established technology. Explore the advantages below:

+Highly flexible technology:

  • Allows plant design to deliver optimal product ratios, which can be adjusted online to match future requirements.

+Optimised heat integration:

  • 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.

+High quality DMF:

  • Process delivers high-quality DMF suitable for all known applications.

+Large capacities:

  • High process output available in a single train.

+Lower environmental impact:

  • Flowsheet includes numerous features to prevent atmospheric emissions and to ensure the plant should fall within legislative limits worldwide.
Core Technologies & Related Processes

Our amination technology brings the Leonard process to life, realising its full potential efficiently, cleanly and productively. Learn more here:

Our DMF flowsheet is one of several technologies we offer to further enhance our methylamines process. Explore Davy methylamines here, along with our additional value-adding flowsheets:


Core Technologies

Our amination technology brings the Leonard process to life, realising its full potential efficiently, cleanly and productively. Learn more here:


Related Processes

Our DMF flowsheet is one of several technologies we offer to further enhance our methylamines process. Explore Davy methylamines here, along with our additional value-adding flowsheets: