HRP940870A2

HRP940870A2 - Production of ethylchlorthioformiates

Info

Publication number: HRP940870A2
Application number: HRP-561/78A
Authority: HR
Inventors: Carlo Galileo Alesandrini Jr
Original assignee: Stauffer Chemical Co
Priority date: 1977-03-09
Filing date: 1994-10-28
Publication date: 1997-10-31

Description

Izvod iz izuma Extract from the invention

Poboljšani postupak za proizvodnju alkil, niži cikloalkil, niži cikloalkilmetil, niži alkenil, fenil, benzil, kloro-supstituirani fenil i izvjesnih haloalkil klorotioformijata reakcijom odgovarajućeg merkaptena sa fozgenom. Postupak se vrši u dvije faze, koje se obje vrše u kontinualnoj tekućoj fazi, u prisustvu aktiviranog ugljičnog katalizatora. Proizvodnja sporednog proizvoda disulfida se minimira a ukupni kapacitet se može povećati. An improved process for the production of alkyl, lower cycloalkyl, lower cycloalkylmethyl, lower alkenyl, phenyl, benzyl, chloro-substituted phenyl and certain haloalkyl chlorothioformates by reaction of the corresponding mercaptene with phosgene. The process is carried out in two phases, both of which are carried out in a continuous liquid phase, in the presence of an activated carbon catalyst. The production of disulfide by-product is minimized and the total capacity can be increased.

Ovo je djelomičan nastavak ranije prijave, serijski broj 636,266, podnjete 28. studenog, 1975. This is a continuation-in-part of an earlier application, Serial No. 636,266, filed Nov. 28, 1975.

Ovaj izum odnosi se na proizvodnju klorotioformijata reakcijom nekog merkaptana se fozgenom u prisustvu aktiviranog ugljičnog katalizatora, This invention relates to the production of chlorothioformate by the reaction of a mercaptan with phosgene in the presence of an activated carbon catalyst,

[image] [image]

U ovom izumu R je alkil, niži cikloalkil-metil, niži ciklo-alkil, niži alkenil, fenil, kloro-supstituirani fenil, benzil ili kloro-supstituirani alkil u kojem se kloro supstituent nalazi tako daleko kao što je -(gama) ugljikov atom, u odnosu na sumporov atom. Pod terminom "alkil" ili "klorosup-stituirani alkil" podrazumjevaju se takve grupe koje imaju 1 do 15, poželjno od 1 do 10, i najpoželjnije od 1 do 6 uglji-kovih atoma, na primjer, metil, etil, n-propil, izopropil, n-butil, sek-butil, izobutil, n-pentil, neopentil, n-heksil, neoheksil, n-heptil, n-oktil, n-decil, n-dodecil i n-tetra-decil. Pod "niži alkenil" podrazumjevaju se takve grupe koje imaju od 2 do 5 ugljikovih atoma i najmanje jednu olefinsku vezu. Pod "niži cikloalkil" podrazumjevaju se cikloali-fatične grupe koje imaju od 3 do 7 ugljikovih atoma, kao što su ciklopropil i cikloheksil. Termin "niži cikloalkil-metil" uključuje grupe koje imaju 3 do 7 ugljikovih atoma u cikloalkil djelu, kao što su ciklopropilmetil i ciklopentilmetil. Termin "klorofenil" uključuje i mono-i poliklorovane benzolove prstenove u kojima klorov atom ili atomi mogu biti različito supstituirani. In this invention, R is alkyl, lower cycloalkyl-methyl, lower cyclo-alkyl, lower alkenyl, phenyl, chloro-substituted phenyl, benzyl or chloro-substituted alkyl in which the chloro substituent is as far away as the -(gamma) carbon atom , relative to the sulfur atom. By the term "alkyl" or "chlorosubstituted alkyl" are meant such groups having from 1 to 15, preferably from 1 to 10, and most preferably from 1 to 6 carbon atoms, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, n-pentyl, neopentyl, n-hexyl, neohexyl, n-heptyl, n-octyl, n-decyl, n-dodecyl and n-tetradecyl. "Lower alkenyl" means such groups having from 2 to 5 carbon atoms and at least one olefinic bond. By "lower cycloalkyl" are meant cycloaliphatic groups having from 3 to 7 carbon atoms, such as cyclopropyl and cyclohexyl. The term "lower cycloalkyl-methyl" includes groups having 3 to 7 carbon atoms in the cycloalkyl moiety, such as cyclopropylmethyl and cyclopentylmethyl. The term "chlorophenyl" includes both mono- and polychlorinated benzene rings in which the chlorine atom or atoms may be variously substituted.

U poželjnoj realizaciji ovog postupka, R je alkil, niži cikloalkil, niži cikloalkil-metil, benzil, fenil ili kloro-supstituirani fenil. Poželjne realizacije za razne mogućnosti za R su: za alkil-takve grupe koje imaju od 1 do 6 ugljikovih atoma, naročito etil, n-propil, izopropil, n-butil, sekbutil, n-pentil i neopentil; za niži cikloalkil-ciklobutil; za niži cikloalkil-metil-ciklopropilmetil i ciklopen-tilmeatil; za niži alkonil- alil; za kloro-supstituirani-fenil-, p-klorofenil; za haloalkile-3 - kloropropil. In a preferred embodiment of this process, R is alkyl, lower cycloalkyl, lower cycloalkyl-methyl, benzyl, phenyl or chloro-substituted phenyl. Preferred embodiments for various possibilities for R are: for alkyl-such groups having from 1 to 6 carbon atoms, especially ethyl, n-propyl, isopropyl, n-butyl, secbutyl, n-pentyl and neopentyl; for lower cycloalkyl-cyclobutyl; for lower cycloalkyl-methyl-cyclopropylmethyl and cyclopentylmethyl; for lower alkonyl-allyl; for chloro-substituted-phenyl-, p-chlorophenyl; for haloalkyl-3 - chloropropyl.

Takvi klorotioformijati su korisni intermedijeri za proizvodnju herbicidno efikasnih tiokarbamata i sličnih spojeva. Reakcija između merkaptana i fozgena za proizvodnju klorotioformijata opisana je u U.S. Patentu 3,165,544 od Harry Tilles-a, koji opisuje provođenje ovog postupka u opremi laboratorijske veličine. Naglašava se da reakcijske temperature treba da se održavaju što je moguće nižim, u suglasnosti sa prihvatljivim reakcijskim brzinama pošto na višim temperaturama počinje da se formira sporedni proizvod - disulfid u značajnim količinama. Maksimalne temperature koje se sugeriraju za ovu reakciju su između 70° i 140°. Such chlorothioformates are useful intermediates for the production of herbicidally effective thiocarbamates and similar compounds. The reaction between mercaptan and phosgene to produce chlorothioformate is described in U.S. Pat. Patent 3,165,544 to Harry Tilles, which describes carrying out this process in laboratory-sized equipment. It is emphasized that the reaction temperatures should be kept as low as possible, in accordance with the acceptable reaction rates, since at higher temperatures a side product - disulfide - begins to form in significant quantities. The maximum temperatures suggested for this reaction are between 70° and 140°.

Jedan postupak koji je korišten za komercijalnu proizvodnju nižih alkilklorotioformijata pomoću ove reakcije koristi dva katalitička ležišta od aktiviranog ugljika postavljena u nizu. Prvo ležište se poželjno nalazi u cjevi višecjevnog reaktora; drugo je u obliku reaktora su pakiranim ležištem koje sadrži jedno katalitičko ležište. Prvi reaktor radi kao kontinualni reaktor sa tekućom fazom; specifičnije kao uspravni cjevni katalitički reaktor, sa polaznim materijalima koji se uvode na dnu i proizvodima koji se uklanjaju iz gornjeg djela. One process that has been used for the commercial production of lower alkyl chlorothioformates using this reaction uses two activated carbon catalytic beds placed in series. The first bed is preferably located in the tube of the multitube reactor; the second is in the form of a packed bed reactor containing one catalytic bed. The first reactor works as a continuous reactor with a liquid phase; more specifically as a vertical tubular catalytic reactor, with feedstocks introduced at the bottom and products removed from the top.

Djelomično izreagirana smjesa se tada uvodi u vrh drugog reaktora, koji funkcionira kao pakirano ležište sa protokom na dolje. To jeste, drugi reaktor radi u kontinualnoj plinovitoj fazi pošto se proizvedeni plinoviti klorovodik kontinualno provodi kroz ležište. Reakcijski proizvodi se odvajaju iz donjeg djela drugog reaktora i propuštaju se nizvodno od aparata za odvajanje klorotioformijata. Nađeno je, međutim, da provođenje ovog postupka daje proizvod čistoće samo između 91 i 95%. Glavna nečistoća je dietildisulfid, prisutan u koncentraciji 3-7%, a najveći dio ostalih nečistoća je di-etilditiokarbonat. Kada se koristi za proizvodnju n-propil-klorotiofirmijata, količina sporedno proizvedenog disulfida varira od 1.5 - 13.7% i prosječno je točno ispod 5%, a čistoća klorotioformijata je u prosjeku oko 93%. The partially reacted mixture is then introduced into the top of the second reactor, which functions as a downflow packed bed. That is, the second reactor works in a continuous gaseous phase, since the produced gaseous hydrogen chloride is continuously carried through the reservoir. The reaction products are separated from the lower part of the second reactor and passed downstream from the chlorothioformate separator. It was found, however, that carrying out this procedure gave a product of only between 91 and 95% purity. The main impurity is diethyldisulfide, present in a concentration of 3-7%, and most of the other impurities are diethyldithiocarbonate. When used to produce n-propyl-chlorothioformate, the amount of by-product disulfide varies from 1.5 - 13.7% and averages just under 5%, and the purity of the chlorothioformate averages around 93%.

Cilj sadašnjeg izuma je da osigura poboljšani postupak za proizvodnju klorotioformijata reakcijom merkaptana i fozgena u prisustvu aktiviranog ugljičnog katalizatora. The object of the present invention is to provide an improved process for the production of chlorothioformate by the reaction of mercaptan and phosgene in the presence of an activated carbon catalyst.

Dalji cilj sadašnjeg izuma je da osigura takav postupak sa minimiranjem sporednog proizvoda - disulfida. A further aim of the present invention is to provide such a process with the minimization of the by-product - disulfide.

Treći cilj sadašnjeg izuma je da osigura takav postupak sa pojačanim proizvodnim kapacitetom. A third objective of the present invention is to provide such a process with enhanced production capacity.

Daljnji cilj sadašnjeg izuma je da osigura takav postupak koji ima dobru temperaturnu kontrolu u reaktorima. A further object of the present invention is to provide such a process which has good temperature control in reactors.

Još uvijek daljnji cilj sadašnjeg izuma je da osigura takav postupak koji ima dobru konverziju merkaptana u klorotioformijat. It is a still further object of the present invention to provide such a process which has a good conversion of mercaptan to chlorothioformate.

Sadašnji izum obuhvaća postupak za proizvodnju klorotiofor-mijata koji ima formulu The present invention comprises a process for the production of a chlorothioformiate having the formula

[image] [image]

,u kojem je R alkil, niži cikloalkil, niži cikloalkil-metil, niži alkenil, fenil, klo-ro-supstituirani fenil, benzil ili kloro-supstituirani alkil gdje se kloro supstituent nalazi najmanje tako daleko kao što je gama ugljikov atom, u odnosu na sumporov atom, reakcijom odgovarajućeg merkaptana sa fozgenom u prisustvu aktiviranog ugljičnog katalizatora koji obuhvaća: , in which R is alkyl, lower cycloalkyl, lower cycloalkyl-methyl, lower alkenyl, phenyl, chloro-substituted phenyl, benzyl or chloro-substituted alkyl where the chloro substituent is at least as far away as the gamma carbon atom, relative to the sulfur atom, by the reaction of the appropriate mercaptan with phosgene in the presence of an activated carbon catalyst that includes:

a) dovođenje u kontakt merkaptana sa fozgenora u prvoj reakcijskoj zoni sa kontinueinora tekućom fazom u prisustvu katalizatora koji obuhvaća aktivirani ugljik; a) contacting the mercaptan from the phosgenor in the first reaction zone with the continuousinor in the liquid phase in the presence of a catalyst comprising activated carbon;

b) odvajanje prvog reakcijskog proizvoda iz prve reakcijske zone; b) separation of the first reaction product from the first reaction zone;

c) dovođenje u kontakt prvog reakcijskog proizvoda sa katalizatorom koji obuhvaća aktivirani ugljik u drugoj zoni sa kontinualnom tekućom fazom; i c) contacting the first reaction product with a catalyst comprising activated carbon in the second zone with a continuous liquid phase; and

d) odvajanje drugog reakcijskog proizvoda koji sadrži klorotioformijat iz druge reakcijske zone. d) separation of the second reaction product containing chlorothioformate from the second reaction zone.

Detaljan opis izuma Detailed description of the invention

Izum je određenije opisan imajući za referencu sliku koja prikazuje generaliziran floušit za provođenje postupka. The invention is more specifically described with reference to a figure showing a generalized flow sheet for carrying out the process.

Na slici, merkaptan u liniji 1 spaja se sa fozgenom u liniji 2 i smjesa se uvodi kroz liniju 4 u donji dio prvog reaktora 10. Reaktor 10 radi sa reaktantima i proizvodima u kontinualnoj tekućoj fazi. Poželjno, je reaktor 10 cjevi reaktor sa pakiranim ležištem koji sadrži mnoštvo cjevi napunjenih sa aktiviranim ugljikom odgovarajuće veličine djelića tako da svaka cjev funkcionira na konvencionalan način kao minijaturni reaktor sa pakiranim ležištem. Reaktanti u struji 4 uvode se u donji dio reaktora, pa tako i u donje djelove pojedinačnih cjevi, i prolaze na gore kroz cjevi. Prosječna iz lažna temperatura je uglavnom između oko 0° i oko 70°C, poželjno između oko 0° i oko 50°C. Interval tlaka je između oko 0 i oko 150 psi, poželjno između 0 i oko 50 psi. In the picture, mercaptan in line 1 is combined with phosgene in line 2 and the mixture is introduced through line 4 into the lower part of the first reactor 10. Reactor 10 operates with reactants and products in a continuous liquid phase. Preferably, the reactor 10 is a tube packed bed reactor containing a plurality of tubes filled with activated carbon of appropriate particle size such that each tube functions in a conventional manner as a miniature packed bed reactor. The reactants in stream 4 are introduced into the lower part of the reactor, and also into the lower parts of the individual pipes, and pass upwards through the pipes. The average false temperature is generally between about 0° and about 70°C, preferably between about 0° and about 50°C. The pressure range is between about 0 and about 150 psi, preferably between 0 and about 50 psi.

Djelomično izreagirani proizvodi iz provog reaktora 10 uklanjaju se iz gornjeg djela ovog reaktora kao preljevna frakcija u liniji 6 i prolaze kroz liniju 8 u drugi reaktor 11. Prema potrebi, plinski proizvodi iz reaktora 10 mogu se odvojiti iz smjese u liniji 6 prije uvođenja u reaktor 11. Reaktor 11 sadrži pakirano ležište 12 od aktiviranog ugljika. Reakcija se završava u reaktoru 11 u kontinualnoj tekućoj fazi. Kao što je prikazano na Slici, ovo se postiže uvođenjem reaktanata u donji dio reaktora 11 tako da ovaj reaktor radi u takozvanom stanju sa "plavijenjem na gore". Reaktor uglavnom radi na prosječnim izlaznim temperaturama između oko 0° i oko 70°C, poželjno između oko 10° i oko 50°C, najpoželjnije na temperaturi unutar ovog intervala ispod 50°C. Interval tlaka je između oko 0 i oko 150 psi, poželjno između oko 0 i oko 50 psi. Vrijeme zadržavanja reaktanata u reaktoru 11 je uglavnom između oko 1 i oko 180 minuta, poželjno između oko 5 i oko 90 minuta. Partially reacted products from reactor 10 are removed from the upper part of this reactor as an overflow fraction in line 6 and pass through line 8 to another reactor 11. If necessary, gas products from reactor 10 can be separated from the mixture in line 6 before being introduced into the reactor 11. The reactor 11 contains a packed bed 12 of activated carbon. The reaction ends in reactor 11 in the continuous liquid phase. As shown in the Figure, this is achieved by introducing the reactants into the lower part of the reactor 11 so that this reactor operates in the so-called "flooding up" state. The reactor generally operates at average outlet temperatures between about 0° and about 70°C, preferably between about 10° and about 50°C, most preferably at a temperature within this interval below 50°C. The pressure range is between about 0 and about 150 psi, preferably between about 0 and about 50 psi. The residence time of the reactants in the reactor 11 is generally between about 1 and about 180 minutes, preferably between about 5 and about 90 minutes.

Reakcijski proizvodi se uklanjaju iz reaktora 11 kroz preljevnu liniju 9, prelaze u bubanj za odvajanje 14 i proizvod - klorotioformijat se uklanja u liniji 15 za daljnje pročišćavanje. Plinski sporedni proizvodi (prvenstveno klorovodik sa nešto neizreagiranog fozgena) uzimaju se iz linije 14 i puštaju se nizvodno od jedinica za pročišćavanje (nisu prikazane) za izoliranje neizreagiranih polaznih materijala za reciklažu i za uklanjanje i daljnje prerade klorovodika. The reaction products are removed from the reactor 11 through the overflow line 9, pass into the separation drum 14 and the product - chlorothioformate is removed in line 15 for further purification. Gaseous by-products (primarily hydrogen chloride with some unreacted phosgene) are taken from line 14 and passed downstream to treatment units (not shown) to isolate unreacted feedstocks for recycling and to remove and further process the hydrogen chloride.

Kada, kao u prijašnjem procesu, drugi reaktor 11 radi kao kontinualni reaktor sa plinskom fazom (npr. kao reaktor sa pakiranim ležištem za nizvodnim protokom) prosječna izlazna temperatura može se također održavati na između oko 0°C i oko 70°C, kao u prijašnjem procesu. Međutim, operacije prema prijašnjem procesu vode do neujednačene temperature duž reaktora usljed slabog toplinskog transfera, tako da se stvaraju lokalizirane zone visokih temperatura, ili "vruća mjesta". Poznato je, iz U.S. Patenta 3,165,544, da nepoželjno visoke temperature vode do formiranja sporednog proizvoda - disulfida. Zato, prisustvo vrućih mjesta u reaktoru 11, povećava mogućnost formiranja ovog sporednog proizvoda. When, as in the previous process, the second reactor 11 is operated as a continuous gas phase reactor (eg as a downstream packed bed reactor) the average outlet temperature can also be maintained at between about 0°C and about 70°C, as in previous process. However, operations under the former process lead to nonuniform temperatures along the reactor due to poor heat transfer, so that localized zones of high temperatures, or "hot spots," are created. It is known, from the U.S. Patent 3,165,544, that undesirably high temperatures lead to the formation of a side product - disulfide. Therefore, the presence of hot spots in reactor 11 increases the possibility of the formation of this side product.

Kada se prakticira postupak korištenjem sadašnjeg izuma, rad drugog reaktora 11 kao reaktora sa pakiranim ležištem sa kontinualnom tekućom fazom dovodi do značajnog smanje-nja formiranja disulfida zato što takve operacije osiguravaju bolji toplinski transfer i uniformniju distribuciju temperature u čitavom katalitičkom ležištu. When practicing the process using the present invention, operation of the second reactor 11 as a packed bed reactor with a continuous liquid phase leads to a significant reduction in disulfide formation because such operations provide better heat transfer and more uniform temperature distribution throughout the catalytic bed.

Operacije prema sadašnjem izumu, sa reaktorom 11 kao kon-tinualnim reaktorom sa tekućom fazom, dovode do povećanja vremena zadržavanja u drugom reaktoru sa istom brzinom protoka kao u prethodnom procesu, za faktor od najmanje oko 10. Na primjer, u prethodnom postupku vrijeme zadržavanja u ovom reaktoru bilo je često reda 4-5 minuta. U sadašnjem postupku vrijeme zadržavanja može biti između oko 5 i oko 180 minuta, ili čak duže, ovisno od brzine protoka. Poželjno je vrijeme zadržavanja između oko 45 i oko 90 ili 120 minuta. Može se rezonski očekivati da operacije sa tako dugim vremenima zadržavanja mogu dovesti do povećanog formiranja sporednog proizvoda; međutim, neočekivano je nađeno da operacije sa tako dugim vremenima zadržavanja ne dovode do povećanog formiranja sporednih proizvoda sve dotle dok se temperatura održava pod dobrom kontrolom. Alternativno, brzina protoka materijala može se povećati tako da se omogućuju operacije pri nižim vremenima zadržavanja u ovom reaktoru i sa povećanjem kapaciteta, a i sa povećanom konverzijom merkaptana u klorotioformijat. Poželjno se brzina protoka može povećati za. 2 - 2 1/2 puta od one koja je korištena ranije. Pri povećanim brzinama protoka, vrijeme zadržavanja u prvom reaktoru se također smanjuje. Operations according to the present invention, with reactor 11 as a continuous liquid phase reactor, lead to an increase in the residence time in the second reactor with the same flow rate as in the previous process, by a factor of at least about 10. For example, in the previous process, the residence time in this reactor was often on the order of 4-5 minutes. In the current process, the residence time can be between about 5 and about 180 minutes, or even longer, depending on the flow rate. A residence time of between about 45 and about 90 or 120 minutes is preferred. It can be reasonably expected that operations with such long retention times may lead to increased by-product formation; however, it has unexpectedly been found that operations with such long residence times do not lead to increased by-product formation as long as the temperature is kept under good control. Alternatively, the material flow rate can be increased to enable operations at lower residence times in this reactor and with increased capacity and increased mercaptan to chlorothioformate conversion. Preferably, the flow rate can be increased by. 2 - 2 1/2 times the one used earlier. At increased flow rates, the residence time in the first reactor also decreases.

Željena temperaturna kontrola u reaktoru 11 i u ukupnom postupku može se povećati uvođenjem viška tekućeg fozgena u sustav, ili kao dio šadrže u liniji 2 ili posebno, u reaktor 10. Dio ili sav ovaj višak ispariće pod normalnim operativnim uvjetima reaktora 11, pa će isparavanje apsorbirati toplinu koja se generira za vrijeme reakcije. The desired temperature control in reactor 11 and in the overall process can be increased by introducing excess liquid phosgene into the system, either as part of the feed in line 2 or separately, into reactor 10. Some or all of this excess will evaporate under normal operating conditions of reactor 11, and the evaporation will absorb the heat generated during the reaction.

Kao alternativni postupak za temperaturnu kontrolu, i također za pomaganje povećanja ukupne proizvodnje klorotioformijata, relativno hladna reciklirana struja 5, dobivena nizvodno od procesnih jedinica (nisu prikazane), i koja sadrži prvenstveno neizreagirane polazne materijale, može se uvesti u sustav. Reciklirana struja u liniji 5 može se uvesti u reaktor 11 preko linija 7 i 8; njeno prisustvo doprinosi održavanju poželjno niske temperature u reaktoru 11, poželjno ispod oko 50°C. Alternativno se reciklirana struja 5 može uvesti preko linija 3 i 4 u prvi reaktor 10. Najpoželjnije temperaturna kontrola se održava kombiniranjem korištenja viška tekućeg fozgena i uvođenjem reciklirane struje u reaktor 11. As an alternative process for temperature control, and also to help increase overall chlorothioformate production, a relatively cool recycle stream 5, obtained downstream of the process units (not shown), and containing primarily unreacted starting materials, can be introduced into the system. Recycled current in line 5 can be introduced into reactor 11 via lines 7 and 8; its presence contributes to maintaining a preferably low temperature in the reactor 11, preferably below about 50°C. Alternatively, the recycled stream 5 can be introduced via lines 3 and 4 into the first reactor 10. Most preferably, temperature control is maintained by combining the use of excess liquid phosgene and the introduction of the recycled stream into the reactor 11.

Operacije prema izumu, kao što će se dalje vidjeti iz primjera koji slijedi, dovodi do konverzije od približno 94% polaznog etilmerkaptana i proizvodnje proizvoda od oko 93% čistoće, koji sadrži uglavnom manje od 1% dietildisulfida. Dalje, korištenje kontinualnog reaktora sa tekućom fazom, kroz povećanje vremena zadržavanja, osigurava veći kapacitet od slične jedinice koja radi korištenjem protoka na dolje u pakiranom reaktoru, u kojem je vrijeme zadržavanja značajno kraće. Nađeno je da su slični rezultati u slučaju n-propil-klorotioformijata, kao što se može vidjeti iz Primjera 3. Na bazi ovih rezultata i općeg poznavanja ovog područja znanosti, na primjer informacija koja se nalazi u U.S. Patentu 3,165,544, treba očekivati slične dobre performanse za druge tipove spojeva koja su ovdje uključena. Kao alternativa tipu reaktora sa "plavljenjem na gore" koji je prikazan na Slici, reaktor 11 može raditi kao kontinualni reaktor sa tekućom fazom na makoji drugi pogodni način, na primjer, kao reaktor sa pakiranim ležištem sa plavljenjem na dolje. The operation of the invention, as will be further seen from the following example, leads to a conversion of approximately 94% of the starting ethyl mercaptan and the production of a product of about 93% purity, containing substantially less than 1% diethyldisulfide. Further, the use of a continuous liquid phase reactor, through increased residence time, provides a higher capacity than a similar unit operating using a downflow packed reactor, in which the residence time is significantly shorter. Similar results were found in the case of n-propyl-chlorothioformate, as can be seen from Example 3. Based on these results and general knowledge in the art, for example information found in U.S. Pat. Patent 3,165,544, similarly good performance should be expected for the other types of compounds included herein. As an alternative to the "flood-up" type of reactor shown in FIG., reactor 11 may be operated as a continuous liquid-phase reactor in some other convenient manner, for example, as a bottom-flood packed bed reactor.

Sljedeći primjeri ilustriraju provođenje sadašnjeg izuma. The following examples illustrate the practice of the present invention.

Primjeri Examples

Primjer 1 Example 1

Koristi se dvoreaktorski sustav kao što je prikazan na Slici koja ima kapacitet za proizvodnju od oko 57,000 funti na dan etil-klorotioformijata. Prvi reaktor je cjevni uspravni reaktor, sa cjevima koje su pakirane sa katalizatorom od aktiviranog ugljika. Drugi reaktor je reaktor sa pakiranim ležištem koji sadrži ležište od ugljičnog katalizatora i radi kao reaktor sa uspravnim protokom. A two-reactor system is used as shown in Fig. which has the capacity to produce about 57,000 pounds per day of ethyl chlorothioformate. The first reactor is a tubular vertical reactor, with tubes packed with an activated carbon catalyst. The second reactor is a packed bed reactor that contains a bed of carbon catalyst and operates as a vertical flow reactor.

U prvi reaktor, koji odgovara reaktoru 10 sa Slike, šaržira se 22.4 1b-mol/sat fozgena i 20.4 1b-mol/sat etilmer-kaptana. Reaktor radi na unutrašnjoj temperaturi od oko 15-40°C, i na vanjskoj temperaturi od oko 50-65°C, i sa izlaznim pritiskom od oko 30-36 psi. Djelomično izreagirani proizvodi iz provog reaktora šaržiraju se u donji dio drugog reaktora zajedno sa recikliranom strujom koja sadrži 10.7 1b-mol/sat fozgena i 4.7 1b-mol/sat etilkloro-tioformijata. Drugi reaktor radi na ulaznoj temperaturi od oko 18-26°C, na izlaznoj temperaturi oko 33-49°C, izlaznom tlaku oko 24-28 psi i sa vremenom zadržavanja oko 75 minuta. 22.4 1b-mol/hour of phosgene and 20.4 1b-mol/hour of ethylmer-captan are charged into the first reactor, which corresponds to reactor 10 from the Figure. The reactor operates at an internal temperature of about 15-40°C, and an external temperature of about 50-65°C, and with an outlet pressure of about 30-36 psi. Partially reacted products from the main reactor are charged to the lower part of the second reactor together with the recycled stream containing 10.7 1b-mol/hour of phosgene and 4.7 1b-mol/hour of ethylchloro-thioformate. The second reactor operates at an inlet temperature of about 18-26°C, an outlet temperature of about 33-49°C, an outlet pressure of about 24-28 psi and a residence time of about 75 minutes.

Konverzija etilmerkaptana u klorotioformijat bila je 94%. Proizvod je dobiven sa 98% čistoćom, i sadrži oko 0.5-1% dietildisulfida i oko 1% dietil-ditiokarbonata. Conversion of ethyl mercaptan to chlorothioformate was 94%. The product is obtained with 98% purity, and contains about 0.5-1% diethyldisulfide and about 1% diethyldithiocarbonate.

Primjer 2 Example 2

Korišten je isti sustav kao u Primjeru 1, ali su brzine protoka materijala povećane da se osigura kapacitet od oko 114,000 1b/dan etilhlorotioformijata. Brzina protoka šaržiranog fozgena i etilmerkaptana bile su 44.8, odnosno 40.8 1b-mol/sat. Brzina protoka reciklaže bila je 21.4 za fozgen i 9.4 1b-mol/sat za etilklorotioformijat. Radne temperature i tlakovi bili su suštinski isti kao u Primjeru 1. Vrijeme zadržavanja materijala u drugom reaktoru smanjeno je na oko 35 minuta. Proizvedeni etil-klorotioformijat dobiven je opet sa 98% Čistoćom, sa 94% konverzijom etilmerkaptana. Sadržaj dietildisulfida u proizvodu bio je oko 0.5-1%; sadržaj dietilditiokarbonata bio je oko 0.5%. The same system as in Example 1 was used, but the material flow rates were increased to provide a capacity of about 114,000 1b/day of ethyl chlorothioformate. The flow rates of batch phosgene and ethylmercaptan were 44.8 and 40.8 1b-mol/hour, respectively. The recycling flow rate was 21.4 for phosgene and 9.4 1b-mol/hour for ethyl chlorothioformate. The operating temperatures and pressures were essentially the same as in Example 1. The residence time of the material in the second reactor was reduced to about 35 minutes. The produced ethyl chlorothioformate was again obtained with 98% purity, with 94% conversion of ethyl mercaptan. The content of diethyldisulfide in the product was about 0.5-1%; the diethyldithiocarbonate content was about 0.5%.

Primjer 3 Example 3

Korišten je dvoreaktorski sustav kao što je prikazan na Slici, koji ima kapacitet za proizvodnju oko 74,000 funti na dan n-propil-klorotioformijata. Prvi reaktor je cjevni reaktor sa protokom na gore, pakiran sa cjevima sa aktiviranim ugljičnim katalizatorom. Drugi reaktor je reaktor sa pakiranim ležištem koji sadrži ležište ugljičnog katalizatora i radi kao reaktor sa protokom na gore. A two-reactor system was used as shown in Figure, which has the capacity to produce about 74,000 pounds per day of n-propyl-chlorothioformate. The first reactor is an upflow tubular reactor packed with tubes with an activated carbon catalyst. The second reactor is a packed bed reactor that contains a bed of carbon catalyst and operates as an upflow reactor.

U prvi reaktor, koji odgovara reaktoru 10 sa Slike, šaržira se 24.6 1b-mol/sat fozgena i 22.4 1b-mol/sat n-propil merkaptana. Struja za reciklažu koja sadrži oko 11 1b-mol/sat fozgena i oko 5 1 b-mol/sat,. n-propilklorotio-formijata također se uvede u reaktor 10. Reaktor radi na ulaznoj temperaturi od oko 15-40°C, sa izlaznom temperaturom oko 40-55°C i sa izlaznim tlakom od oko 26-30 psi. Djelomično izreagirani proizvodi iz prvog reaktora šaržiraju se u donji dio drugog reaktora. Drugi reaktor radi sa ulaznom temperaturom od oko 40-55°C, izlaznom temperaturom oko 40-55°C, izlaznim tlakom oko 22-26 psi i sa vremenom zadržavanja oko 75 minuta. 24.6 1b-mol/hour of phosgene and 22.4 1b-mol/hour of n-propyl mercaptan are charged into the first reactor, which corresponds to reactor 10 from the Figure. A recycle stream containing about 11 1b-mol/hr of phosgene and about 5 1 b-mol/hr,. n-Propylchlorothioformate is also introduced into reactor 10. The reactor is operated at an inlet temperature of about 15-40°C, with an outlet temperature of about 40-55°C and an outlet pressure of about 26-30 psi. Partially reacted products from the first reactor are fed into the lower part of the second reactor. The second reactor operates with an inlet temperature of about 40-55°C, an outlet temperature of about 40-55°C, an outlet pressure of about 22-26 psi and a residence time of about 75 minutes.

Konverzija n-propil-merkaptana u klorotioformijat bila je 94%. Proizvod je dobiven sa čistoćom 98-99%. The conversion of n-propyl mercaptan to chlorothioformate was 94%. The product was obtained with a purity of 98-99%.

Claims

1. Process for the production of chlorothioformate of the formula [image] wherein R is alkyl, lower cycloalkyl-methyl, lower cyclo-alkyl, lower alkenyl, phenyl, chloro-substituted phenyl, benzyl or chloro-substituted alkyl in which the chloro-substituent is located at least as far as the gamma-carbon atom from sulfur atom, characterized by comprising: a) bringing mercaptan of the formula RSH into contact with phosgene in the first reaction zone with a continuous liquid phase in the presence of a catalyst comprising activated carbon; b) separation of the first reaction product from the first ceaction zone; c) bringing the first reaction product into contact with a catalyst containing activated carbon in a second reaction zone with a continuous liquid phase; and d) separation of the second reaction product comprising chlorothioformate from the second reaction zone.

2. The method according to Claim 1, characterized in that R is alkyl.

3. Process according to Claim 2, characterized in that R is alkyl having from 1 to 10 carbon atoms.

4. Process according to Claim 2, characterized in that R is alkyl having from 1 to 6 carbon atoms.

5. Process according to Claim 4, characterized in that R is n-propyl.

6. Process according to Claim 1, characterized in that R is lower cycloalkyl.

7. Process according to Claim 6, characterized in that R is cyclohexyl.

8. Process according to Claim 1, characterized in that R is benzyl.

9. Process according to Claim 1, characterized in that R is phenyl.

10. Process according to Claim 1, characterized in that R is chloro-substituted phenyl.

11. Process according to Claim 10, characterized in that R is p-chlorophenyl.

12. The method according to Claim 1, characterized in that phase (c) is performed at an average outlet temperature between about 0° and about 70°C.

13. The method according to Claim 1, characterized in that phase (c) is performed at an average outlet temperature between about 10° and about 50°C.

14. The method according to Claim 1, characterized in that phase (c) is performed at an average outlet temperature between about 10° and below about 50°C.

15. Process according to Claim 1, characterized in that phase (c) is performed with a retention time between about 5 and about 180 minutes.

16. The method according to Claim 15, characterized in that phase (c) is carried out with a retention time between about 45 and about 180 minutes.

17. The method according to Claim 1, characterized in that an excess of liquid phosgene is introduced into phase (a).

18. The process according to Claim 1, characterized in that an excess of liquid phosgene is introduced into phase (c).

19. The process according to Claim 1, characterized in that it further comprises isolating unreacted starting materials from the product from stage (d) and recycling said unreacted starting materials in stage (c)

20. The process according to Claim 1, characterized in that it further comprises isolating unreacted starting materials from the product from phase (d) and recycling said unreacted starting materials in phase (a).

21. The method according to Claim 1, characterized in that it further comprises isolating chlorothioformate from the product of phase (d).

22. The method according to Claim 1, characterized in that in phase (c) the first reaction product is introduced into the lower part of the reactor with a packed bed containing a bed of activated carbon catalyst.

23. Process for the production of alkyl-chlorothioformate by the reaction of alkyl mercaptan with phosgene in the presence of a catalyst comprising activated carbon in a system comprising two reactors operating in series, indicated by the fact that the second reactor operates as a reactor with a continuous liquid phase.

24. The process according to Claim 23, characterized in that the second reactor operates as a packed bed reactor with upward flow.

25. The method according to Claim 23, characterized in that alkyl mercaptan and alkyl chlorothioformate have from 1 to 6 carbon atoms in the alkyl group.

26. The method according to Claim 25, characterized in that the alkyl group is n-propyl.