US010227284B2 (12 ) United States Patent (10 ) Patent No. : US 10 , 227 ,284 B2 Krill et al. (45 ) Date of Patent: Mar. 12 , 2019 (54 ) METHOD FOR PREPARING 7 ,423 , 173 B2 9 / 2008 Krill et al. ALPHA - HYDROXYCARBOXYLIC ACID 8 , 569 , 539 B2 10 / 2013 May et al . ESTERS IN WHICH AMMONIA IS 8 , 975 ,440 B2 3 / 2015 May et al. 9 ,428 ,437 B2 8 /2016 May et al. RECYCLED 2009 /0209781 Al 8 / 2009 Ackermann et al . ( 71 ) Applicant: Evonik Roehm GmbH , Darmstadt FOREIGN PATENT DOCUMENTS (DE ) DE 10 2013 213 699 Al 1 / 2015 ( 72 ) Inventors : Steffen Krill , Muehltal (DE ); Belaid EP 0 922 674 A1 6 / 1999 Ait Aissa , Darmstadt (DE ) ; Alexander EP 0 941 984 A2 9 / 1999 EP 0 941 984 A3 9 / 1999 May, Seeheim - Jugenheim (DE ) ; Marcel EP 0 945 423 B1 5 / 2003 Treskow , Darmstadt (DE ) EP 2018 362 A1 1 / 2009 EP 2 415 750 A12 / 2012 ( 73 ) Assignee : Evonik Roehm GmbH , Darmstadt JP 6 - 345692 A 12 / 1994 (DE ) WO WO 2007 / 131829 A1 11 /2007 WO 2008 / 009503 A11 / 2008 ( * ) Notice : Subject to any disclaimer, the term of this WO WO 2013 /026603 Al 2 / 2013 patent is extended or adjusted under 35 U . S . C . 154 ( b ) by 0 days . OTHER PUBLICATIONS (21 ) Appl . No. : 15 /508 , 200 Of Turk et al . “ Activated Carbon Systems for Removal of Light Gases " 1992 , 221 -228 . * ( 22 ) PCT Filed : Sep . 4 , 2015 U . S . Appl . No . 14 / 129, 811, filed Dec . 27, 2013 , US 2014 -0135521 Al, Koestner, et al. ( 86 ) PCT No. : PCT/ EP2015 / 070196 U . S . Appl. No. 15 /323 , 888 , filed Jan . 4 , 2017 , US 2017 -0144960 A1, Krill, et al. $ 371 ( c ) ( 1 ), U . S . Appl. No . 15 /316 ,685 , filed Dec . 6 , 2016 , Aissa . ( 2 ) Date : Mar. 2 , 2017 U . S . Appl . No . 14 / 900 , 403 , filed Dec . 21, 2015, US 2016 - 0137583 A1, Krill , et al. ( 87) PCT Pub . No. : WO2016 /037928 U . S . Appl . No . 15 / 127 ,937 , filed Sep . 21, 2016 , US 2017 -0101322 A1, May , et al . PCT Pub . Date : Mar. 17 , 2016 International Search Report dated Nov . 4 , 2015 in PCT/ EP2015 / 070196 filed Sep . 4 , 2015 . (65 ) Prior Publication Data European Search Report dated Feb . 25 , 2015 in European Appli US 2017 /0283364 A1 Oct. 5 , 2017 cation 14184249 . 2 filed Sep . 10 , 2014 . Klaus Weissermel , et al. “ Industrial Organic Chemistry ” , 4th edition ( 30 ) Foreign Application Priority Data Sohio - Process , 2003, pp . 306 - 309 with cover pages . Hans - Jörg Bart , et al. “ Adsorption ” , Ullmann ' s Encyclopedia of Sep. 10 , 2014 ( EP ) .. .. .. .. 14184249 Industrial Chemistry , vol . 1 , 2012 , pp . 549 -620 . Ernst Gail , et al . “ Cyano Compounds , Inorganic” , Ullmann ' s Ency (51 ) Int . CI. clopedia of Industrial Chemistry , 5th Edition on CD ROM , vol . 10 , C07C 67 /20 ( 2006 .01 ) 2012 , pp . 673 -710 . BOIJ 20 / 20 ( 2006 .01 ) C01C 1 / 02 ( 2006 . 01 ) * cited by examiner C01C 3 /02 ( 2006 . 01) (52 ) U . S . CI. Primary Examiner — Ana Z Muresan CPC .. C07C 67 /20 (2013 .01 ) ; B01J 20 /20 ( 74 ) Attorney , Agent, or Firm — Gruneberg and Myers (2013 .01 ) ; C01C 1/ 024 ( 2013 .01 ) ; C01C PLLC 3 /0212 (2013 .01 ) ; C01C 3 /0208 ( 2013 .01 ) ( 58 ) Field of Classification Search (57 ) ABSTRACT None The present invention relates to a process for preparing See application file for complete search history . alpha -hydroxycarboxylic esters proceeding from hydrogen cyanide , wherein the ammonia formed in the step of alco ( 56 ) References Cited holysis of the corresponding alpha -hydroxycarboxamide is recycled into a hydrogen cyanide preparation process after a U . S . PATENT DOCUMENTS purification step . 6 ,075 , 162 A 6 / 2000 Kida 6 ,096 , 173 A 8 /2000 Von Hippel et al . 11 Claims, 1 Drawing Sheet U . S . Patent Mar . 12 , 2019 US 10, 227 , 284 B2 wwwwwwwwwwwahaha 0 mm * * US 10 , 227 , 284 B2 METHOD FOR PREPARING atoms, which especially comprises 1 - 20 , preferably 1 - 10 and ALPHA -HYDROXYCARBOXYLIC ACID especially 1 - 5 carbon atoms . The carboxamide may bear 1 , ESTERS IN WHICH AMMONIA IS 2 , 3 , 4 or more groups having the formula CONR ' R " . RECYCLED These especially include compounds of the formula 5 R ( CONR 'R " ) , in which the R radical is a group having FIELD OF THE INVENTION 1 - 30 carbon atoms, especially comprising 1 - 20 , preferably 1 - 10 , especially 1 - 5 and more preferably 2 - 3 carbon atoms, The present invention relates to a process for preparing R ' and R " are each as defined above and n is an integer in alpha- hydroxycarboxylic esters (HCEs ) proceeding from the range of 1 - 10 , preferably 1 - 4 and more preferably 1 or hydrogen cyanide , wherein the ammonia formed in the step 1 2 . of alcoholysis of the corresponding alpha -hydroxycarbox - The expression " group having 1 to 30 carbon atoms” amide (HCA ) is recycled into a hydrogen cyanide prepara denotes radicals of organic compounds having 1 to 30 tion process after a purification step . carbon atoms. It includes not only aromatic and heteroaro 16 matic groups but also aliphatic and heteroaliphatic groups , BACKGROUND OF THE INVENTION for example alkyl, cycloalkyl, alkoxy , cycloalkoxy , The preparation of HCEs is sufficiently well known from cycloalkylthio and alkenyl groups . These latter groups may the prior art. More particularly , the applications EP 2018362 be branched or unbranched . and WO 2013 /026603 describe corresponding processes According to the invention , aromatic groups are radicals wherein the alcoholysis is effected in the liquid phase under® 2020 of mono - or polycyclic aromatic compounds preferably pressure and ammonia formed is distilled off at pressures comprising 6 to 20 , more particularly 6 to 12 , carbon atoms . greater than 1 bar , or the HCE formed is removed via the gas Heteroaromatic groups are aryl radicals in which at least one phase . CH group has been replaced by N and /or at least two However , the major problem with this prior art, or else in adjacent CH groups have been replaced by S , NH or O . known processes in which said alcoholysis is effected in the 25 Aromatic or heteroaromatic groups preferred in accor gas phase , is that the isolated ammonia , when recycled into dance with the invention derive from benzene, naphthalene , the hydrogen cyanide preparation process , results in con biphenyl , diphenyl ether , diphenylmethane, diphenyldim siderable losses of catalyst activity even within a short time ethylmethane , bisphenone , diphenyl sulphone , thiophene , and makes it impossible to operate the plant economically . furan , pyrrole , thiazole , oxazole , imidazole , isothiazole , 30 isoxazole , pyrazole , 1 , 3 , 4 -oxadiazole , 2 , 5 - diphenyl- 1 , 3 , 4 SUMMARY OF THE INVENTION oxadiazole , 1 , 3 , 4 - thiadiazole , 1 , 3 , 4 - triazole , 2 , 5 - diphenyl- 1 , 3 , 4 - triazole , 1 , 2 , 5 - triphenyl - 1 , 3 , 4 - triazole , 1 , 2 , 4 -oxadiazole , The problem addressed by present invention is therefore 1 , 2 , 4 - thiadiazole , 1 , 2 , 4 - triazole , 1 , 2 , 3 - triazole , 1 , 2 , 3 , 4 - tetra that of processing the ammonia obtained from the prepara zole , benzo [ b ]thiophene , benzo [ b ] furan , indole , benzo [ c ] tion of HCEs proceeding from hydrogen cyanide such that 35 thiophene , benzo [ c ] furan , isoindole, benzoxazole , benzothi it can be recycled without any problem , i . e . without losses azole , benzimidazole , benzisooxazole , benzisothiazole , in reaction time, yield and quality , into a hydrogen cyanide benzopyrazole , benzothiadiazole , benzotriazole , dibenzo preparation process . furan , dibenzothiophene, carbazole , pyridine, bipyridine , pyrazine, pyrazole , pyrimidine, pyridazine, 1 , 3 , 5 - triazine , BRIEF DESCRIPTION OF THE DRAWING 40 1 , 2 , 4 - triazine , 1 , 2 , 4 , 5 -triazine , tetrazine, quinoline , isoqui noline , quinoxaline , quinazoline , cinnoline , 1 , 8 - naphthyri FIG . 1 is schematic of a reaction plant. dine , 1, 5 -naphthyridine , 1 , 6 -naphthyridine , 1 , 7 -naphthyri These problems, and further problems which have not dine, phthalazine, pyridopyrimidine, purine, pteridine or been mentioned explicitly , are surprisingly solved by the quinolizine, 4H - quinolizine , diphenyl ether , anthracene , inventive provision of a process for preparing HCEs pro - 45 benzopyrrole , benzoxathiadiazole , benzoxadiazole , benzo ceeding from hydrogen cyanide, characterized in that pyridine , benzopyrazine , benzopyrazidine, benzopyrimi ammonia formed in the step of alcoholysis of the corre dine, benzotriazine, indolizine, pyridopyridine, imidazopy sponding alpha -hydroxycarboxamide , after a purification rimidine , pyrazinopyrimidine , carbazole , acridine , step , is recycled into the hydrogen cyanide preparation phenazine , benzoquinoline , phenoxazine , phenothiazine , process (HCN process ) still comprising at least one alky - 50 acridizine, benzopteridine , phenanthroline and phenan lamine . This solution is surprising in that the inventive threne , any of which may also optionally be substituted . purification step does not remove all the impurities from the Preferred alkyl groups include methyl, ethyl, propyl , ammonia formed from the alcoholysis reaction , especially isopropyl, 1 - butyl, 2 -butyl , 2 -methylpropyl , tert -butyl , pen alkylamines , and problem - free operation of an HCN process tyl, 2 -methylbutyl , 1 , 1 - dimethylpropyl, hexyl , heptyl , octyl, 55 1 , 1 , 3 ,3 - tetramethylbutyl , nonyl, 1 - decyl, 2 - decyl , undecyl , is nevertheless possible . dodecyl, pentadecyl and eicosyl. DETAILED DESCRIPTION OF THE Preferred cycloalkyl groups include cyclopropyl, INVENTION cyclobutyl, cyclopentyl , cyclohexyl, cycloheptyl and cyclooctyl, any of which may optionally