I am trying to send out a list of emails using an Org Wide Email address via apex but it is timing out. The emails are sent out quickly without any issues when I don't use the setOrgWideEmailAddressId() function. This is an unacceptable user experience because the page keeps on loading until it times out. 

Unfortunately I need to use an org wide email address because the email must be sent from a generic email, not the logged in user's.

To test out the functionality on its own I executed the following code snippet as annonymous apex and it took 3.2 minutes to finish executing. This is just for a single email.

List<Messaging.Email> emails = new List<Messaging.Email>();
EmailTemplate template = [SELECT Name, Markup, HtmlValue, Body, DeveloperName FROM EmailTemplate WHERE DeveloperName = 'Some_Email_Template'];
OrgWideEmailAddress replyEmail = [SELECT ID, DisplayName FROM OrgWideEmailAddress WHERE Address =: 'address@sample.com'];

// The logic here is repeated in a for loop for various contacts
Messaging.SingleEmailMessage currEmail =  new Messaging.SingleEmailMessage();

currEmail.setTemplateId(template.Id);
currEmail.setTargetObjectId('003S000000QcNfl'); // Add a contact ID
currEmail.setWhatId('701S00000007YTgIAM'); // Set a campaign ID
currEmail.setOrgWideEmailAddressId(replyEmail.Id);

// This is why I am putting the emails in a list, then sending them all
emails.add(currEmail);

Messaging.sendEmail(emails);

 Last execution at 11/30 13:38:44 in 192,171 milliseconds.

Is there a reason why this takes so long to complete when running as an annonymous apex script? In the UI it times out.

OR
 

Is there another way I can achieve this without providing an unacceptable user experience?